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GNC Vitamin C 1000 MG
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GNC Vitamin C 1000 MG360 Vegetarian Caplets
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- With bioflavonoids & rose hips
- A protective antioxidant that provides immune support*
* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
- Supplement Facts
As a dietary supplement, take one to two caplets daily. For maximum benefits, take as directed every day.
Serving Size 1 Caplet Servings Per Container 360 Amount Per Serving % DV Vitamin C (as Ascorbic Acid) 1000.00 mg 1667% Citrus Bioflavonoids Complex 4:1 25.00 mg ** ** Daily Value (DV) not established
- Health Notes
Vitamin CVitamin C
- Reliable and relatively consistent scientific data showing a substantial health benefit.
- Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
- For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
Our proprietary "Star-Rating" system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
This supplement has been used in connection with the following health conditions:Immune System SupportStudies have shown that vitamin C may support immune function, protecting against or reducing the symptoms of many different infections, such as bronchitis, common cold, cold sores, flu, and hepatitisSee Related Conditions (7)CloseCommon Cold and Sore ThroatDose: 1 to 4 grams dailyStudies have shown that taking vitamin C may make your cold shorter and less severe.(more)InfectionDose: 1 to 4 grams dailyVitamin C has antiviral activity, and may help prevent viral infections or, in the case of the common cold, reduce the severity and duration of an infection.(more)BronchitisDose: 200 mg dailyIn a double-blind study of elderly patients hospitalized with acute bronchitis, those given vitamin C improved to a significantly greater extent than those who were given a placebo. (more)Immune FunctionDose: Consult a qualified healthcare practitionerVitamin C stimulates the immune system. While taking it has only a small effect in preventing colds, it does significantly reduce the duration of a cold when taken at the onset.(more)InfluenzaDose: 100 mg dailySupplementing with vitamin C may reduce your flu risk.(more)Cold SoresDose: 200 mg with 200 mg flavonoids, three to five times dailyVitamin C plus flavonoids may help speed cold sore healing. (more)Pre- and Post-Surgery Health and Vitamin C DeficiencyDose: 100 to 250 mg once or twice per dayVitamin C supports immune function and is a critical nutrient for wound healing. Supplementing with it may decrease the risk of excessive bleeding in the surgical setting.(more)Skin ProtectionVitamin C plays a role in all kinds of skin protection, reducing bruising, strengthening capillaries, and repairing skin healing from sunburn, wounds, and ulcers.See Related Conditions (9)CloseSunburnDose: 2,000 to 3,000 mg vitamin C and 1,000 to 2,000 IU vitamin EAntioxidants may protect the skin from sunburn due to free radical-producing ultraviolet rays. Combinations of vitamin E and C offer protection against ultraviolet rays.(more)Wound HealingDose: 1 to 3 grams dailyTaking vitamin C may promote connective tissue repair.(more)SunburnDose: Apply a formula containing 2% vitamin E, 5% vitamin C, and 1% to 2.5% melatonin before sun exposure A topically applied combination of melatonin, vitamin C, and vitamin E may boost the protection from traditional sunscreens.(more)SunburnDose: Apply a formula containing 2% vitamin E and 5% vitamin C before sun exposureStudies have found sunscreen-like effects from topical application of the vitamin C and vitamin E combination.(more)Skin UlcersDose: 1,000 mg dailySupplementing with vitamin C may help prevent skin ulcers and speed healing.(more)EczemaDose: Refer to label instructionsVitamin C might be beneficial in treating eczema by affecting the immune system.(more)BoilsDose: Refer to label instructions(more)Progressive Pigmented PurpuraDose: Refer to label instructions(more)VitiligoDose: Refer to label instructionsVitamin C has been shown to be effective at skin repigmentation in people with vitiligo.(more)Heart & Circulatory HealthVitamin C has been shown to play a role in many of the major heart-health markers: high cholesterol, artery health, high blood pressure, and heart attack.See Related Conditions (7)CloseHigh CholesterolDose: 1,000 mg dailyVitamin C appears to protect LDL cholesterol from damage, and in some trials, cholesterol levels have fallen when people supplement with vitamin C.(more)Capillary FragilityDose: Treat deficiency with up to 1 gram dailyIn cases of deficiency, vitamin C has been shown to increase capillary strength, in seniors and people with diabetes in particular.(more)AtherosclerosisDose: 250 mg twice per day Supplementing with vitamin C may help reverse the progression of atherosclerosis and protect against heart disease.(more)HypertensionDose: Refer to label instructionsSome doctors recommend that people with hypertension supplement with vitamin C, which has been found to have a blood pressure–lowering effect.(more)Heart AttackDose: Refer to label instructionsVitamin C has been reported to protect blood vessels from problems associated with heart attack risk in a variety of ways.(more)Chronic Obstructive Pulmonary DiseaseDose: Refer to label instructionsIn one study, people who got more vitamin C from their diet were less likely to be diagnosed with bronchitis, however, vitamin C has not been studied in relation to COPD.(more)Heart Attack and Vitamin C DeficiencyDose: 100 to 200 mg dailyTaking vitamin C may reduce heart attack risk in people who are deficient.(more)Oral Health Since the discovery that it cures scurvy, vitamin C has been known to play a role in oral health. It may also improve gum disease in people who are deficient in vitamin C, and has been shown to help improve bad breath and speed the healing of cold sores and leukoplakia.See Related Conditions (3)CloseGingivitisDose: 300 mg dailyIf you are deficient in vitamin C, supplementing with this vitamin may improve your overall gum health.(more)GingivitisDose: 300 mg of vitamin C, plus 300 mg of flavonoids dailyIn one study, supplementing with vitamin C plus flavonoids improved gum health in a group of people with gingivitis.(more)Women's HealthVitamin C has been shown to support various aspects of the reproductive cycle, particularly infertility due to a luteal phase defect, protecting against blood loss in women with heavy periods, and relieving hot flashes in menopausal women.See Related Conditions (6)CloseDysmenorrheaDose: 200 mg niacin daily, 300 mg vitamin C daily, and 60 mg rutin daily througout menstrual cycle; for cramps: 100 mg niacin every two to three hoursSupplementing with a combination of vitamin B3, vitamin C, and the flavonoid rutin resulted in a 90% effectiveness for relieving menstrual cramps in one study.(more)Pregnancy and Postpartum SupportDose: 100 mg dailySupplementing with vitamin C during pregnancy may reduce the risk of premature rupture of membranes (PROM).(more)EndometriosisDose: 1,000 mg vitamin C and 1,200 IU vitamin E dailyA combination of vitamin C and vitamin E can help lessen the pain of endometriosis.(more)Female Infertility and Luteal Phase DefectDose: 750 mg dailyVitamin C has been shown to improve fertility in woman with a uterine condition known as luteal phase defect.(more)MenopauseDose: Refer to label instructionsA combination of vitamin C and the flavonoid hesperidin were reported to relieve hot flashes in menopausal women.(more)MenorrhagiaDose: Refer to label instructionsVitamin C protects capillaries (small blood vessels) from damage. In so doing, it might protect against the blood loss of menorrhagia.(more)Stress & Mood ManagementProlonged elevated stress hormones in the body are known to be hard on health. According do some studies, supplementing with vitamin C may help normalize stress-hormone levels.See Related Conditions (1)CloseStressDose: 1 to 3 grams dailyStudies have shown that supplementing with vitamin C helps to normalize stress-hormone levels.(more)Eye Health SupportUse of vitamin C supplements is associated with reduced cataract risk, and supplementing with vitamin C has been found to improve intraocular pressure in people with glaucoma.See Related Conditions (3)CloseGlaucomaDose: At least 2 grams dailySupplementing with vitamin C may help reduce intraocular pressure.(more)Macular DegenerationDose: Refer to label instructionsSunlight triggers oxidative damage in the eye, which in turn can cause macular degeneration. Vitamin C protects against oxidative damage and may reduce macular degeneration risk.(more)CataractsDose: 500 to 1,000 mg dailySupplementing with vitamin C, an important nutrient for healthy vision, has been linked with lower risk of developing cataracts.(more)Blood Sugar & Diabetes SupportVitamin C may protect against eye damage associated with diabetes, and also improve several health markers for both type 1 and type 2 diabetes, including reducing sorbitol levels, urinary protein loss, and glycosylation.See Related Conditions (6)CloseType 2 DiabetesDose: 500 mg twice per daySupplementing with vitamin C may benefit people with type 2 diabetes in several ways, including by reducing sorbitol levels, urinary protein loss, and glycosylation.(more)Pancreatic InsufficiencyDose: 540 mg dailyTaking antioxidant supplements, such as vitamin C, may lessen pain and prevent pancreatitis recurrences.(more)Type 1 DiabetesDose: 500 mg twice per daySupplementing with vitamin C may benefit people with type 1 diabetes in several ways, including by reducing sorbitol levels, urinary protein loss, glycosylation, and eye damage.(more)HypoglycemiaDose: Refer to label instructionsVitamin C helps control blood sugar levels in people with diabetes, and since there are similarities in the way the body regulates high and low blood sugar levels, it might be helpful for hypoglycemia as well.(more)Type 1 DiabetesDose: Refer to label instructionsA combination of the antioxidants selenium, vitamin A, vitamin C, and vitamin E has been shown to improve diabetic retinopathy.(more)Type 1 Diabetes and Diabetic RetinopathyDose: Refer to label instructionsAntioxidant nutrients including selenium, vitamin A, vitamin C, and vitamin E may combat free radicals associated with diabetic retinopathy.(more)Menstrual & PMS SupportStudies show that vitamin C supports several aspects of the menstrual cycle. When used in combination with certain nutrients, it may improve symptoms of endometriosis, and offer some protection against blood loss in women with heavy periods.See Related Conditions (3)CloseAllergy SupportDouble-blind research has shown vitamin C may improve bronchial symptoms in people with asthma. Circumstantial evidence suggests that vitamin C might also offer some relief from hay fever, hives, and sinusitis. See Related Conditions (4)CloseAsthmaDose: 1,000 to 1,500 mg dailySupplementing with vitamin C reduces the tendency of the bronchial passages to go into spasm, an action that has been confirmed in double-blind research.(more)Hay FeverDose: Refer to label instructionsVitamin C has antihistamine activity, and supplementing with it has been reported to help people with hay fever.(more)HivesDose: Refer to label instructionsHigh amounts of vitamin C might help people with hives by lowering histamine levels.(more)Digestive SupportVitamin C may help repair damage caused by gastritis and or peptic ulcer due to bacterial infection. See Related Conditions (4)CloseGastritisDose: 5 grams dailyVitamin C may reduce free radical damage in the stomach lining in the case of gastritis caused by the bacteriaH. pylori.(more)Peptic UlcerDose: Refer to label instructionsVitamin C may be useful in treating peptic ulcers because of its ability to help eradicate H. pylori(more)GallstonesDose: Refer to label instructionsVitamin C is needed for the body to convert cholesterol to bile acids and may help reduce symptoms of gallstones.(more)Joint HealthSupplementing with vitamin C may help reduce uric acid levels, which might lower risk of gout attacks.See Related Conditions (2)CloseGoutDose: 0.5 to 8 grams dailySupplementing with vitamin C might reduce the risk of gout attacks, as it appears to help reduce uric acid levels.(more)Low Back PainDose: Refer to label instructionsA preliminary report suggested that vitamin C helped many people avoid surgery for their disc-related low back pain.(more)Kidney & Urinary Tract HealthSupplementing with vitamin C may help reduce sorbitol levels, urinary protein loss, and glycosylation in people with diabetes. It's also used as a treatment for acute urinary tract infections and may reduce recurrence in people who are prone to UTIs. See Related Conditions (1)CloseUrinary Tract InfectionDose: Refer to label instructionsSupplementing with vitamin C may treat acute UTIs and help people who are prone to recurrent UTIs.(more)Healthy Pregnancy & New BabyVitamin C may support a healthy pregnancy by decreasing risk of premature birth complications and relieving morning sickness symptoms.See Related Conditions (1)CloseChildren's HealthIn children with autism, preliminary research suggests that vitamin C may be beneficial for a hormone pathway, leading to less severe symptoms. Vitamin C supports the immune system and may protect against viral infections, including measles and chicken pox. Structure/Function: Vitamin C is a water-soluble vitamin that may support the body’s immune system, along with other important functions. See Related Conditions (3)CloseAutismDose: 1 gram per 20 lbs (9 kg) body weight per day In one trial, autistic children given vitamin C had less severe symptoms than those taking placebo, possibly because vitamin C affects a hormone pathway typically disturbed in children with autism.(more)Childhood DiseasesDose: Refer to label instructionsVitamin C enhances the immune system and may protect against viral infections, including measles and chicken pox.(more)Ear InfectionsDose: Refer to label instructionsSupplementing with vitamin C stimulates the immune system and may help prevent ear infections.(more)Menopause SupportA combination of vitamin C and the flavonoid hesperidin has been reported to relieve hot flashes.See Related Conditions (1)CloseEar Health SupportSupplementing with vitamin C stimulates the immune system, so it may theoretically help prevent ear infections.See Related Conditions (1)CloseBrain HealthVitamin C in combination with other nutrients may help with certain neurological disorders, such as potentially delaying need for medication in people Parkinson’s disease or lessening symptoms of autism or alcohol withdrawal.See Related Conditions (3)CloseSchizophreniaDose: Consult a qualified healthcare practitionerPeople with schizophrenia may require more vitamin C than the general population. In one trial, vitamin C reduced hallucinations, suspiciousness, and disorganized thoughts.(more)Age-Related Cognitive DeclineDose: Refer to label instructionsUse of vitamin C, alone or with vitamin E, has been associated with better cognitive function and a reduced risk of certain forms of dementia (not including Alzheimer's disease).(more)Bipolar DisorderDose: Refer to label instructionsVitamin C helps the body reduce its load of vanadium, a mineral that adversely influences bipolar disorder. It has improved symptoms of depression and mania in some studies.(more)FitnessVitamin C has been shown to enhance athletic performance by reducing pain and speeding recovery after intense exercise, protecting against and repairing free-radical damage, and correcting deficiencies, if they exist.See Related Conditions (2)CloseAthletic Performance and Reducing Pain and Speeding Muscle Strength Recovery after Intense ExerciseDose: 400 mg daily for several days before and after intense exerciseTaking vitamin C for several days before and after intense exercise may reduce pain and speed muscle strength recovery.(more)Athletic Performance and Vitamin C DeficiencyDose: If deficient: 100 to 200 mg dailyAntioxidants, including vitamin C, neutralize exercise-related free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Especially in cases of vitamin C deficiency, supplementing with the vitamin may improve exercise performance.(more)Men's HealthStudies show that vitamin C’s antioxidant effects may protect male fertility.See Related Conditions (1)CloseMale Infertility and Sperm AgglutinationDose: 1,000 mg dailyVitamin C protects sperm from oxidative damage and keeps sperm from sticking together.(more)AmenorrheaDose: Refer to label instructionsVitamin C combined with the drug clomiphene, which affects female hormone levels, is more effective at stimulating ovulation in women with amenorrhea than either substance alone. (more)Common Cold and Sore ThroatDose: 1 to 4 grams daily
A review of 21 controlled trials using 1 to 8 grams of vitamin C per day found that "in each of the twenty-one studies, vitamin C reduced the duration of episodes and the severity of the symptoms of the common cold by an average of 23%."1 The optimum amount of vitamin C to take for cold treatment remains in debate but may be as high as 1 to 3 grams per day, considerably more than the 120 to 200 mg per day that has been suggested as optimal intake for healthy adults. A review of 23 controlled trials found that vitamin C supplementation produces a greater benefit for children than for adults.2 The same review found that a daily amount of 2 grams or more was superior to a daily amount of 1 gram at reducing the duration of cold symptoms.ReferencesInfectionDose: 1 to 4 grams daily
Vitamin C has antiviral activity, and may help prevent viral infections1 or, in the case of the common cold, reduce the severity and duration of an infection.2 Most studies on the common cold used 1 to 4 grams of vitamin C per day.ReferencesBronchitisDose: 200 mg daily
In a double-blind study of elderly patients hospitalized with acute bronchitis, those who were given 200 mg per day of vitamin C improved to a significantly greater extent than those who were given a placebo.1 The common cold may lead to bronchitis in susceptible people, and numerous controlled studies, some double-blind, have shown that vitamin C supplements can decrease the severity and duration of the common cold in otherwise healthy people.2
Vitamin C and vitamin E may prevent oxidative damage to the lung lipids by environmental pollution and cigarette smoke exposure. It has been suggested that amounts in excess of the RDA (recommended dietary allowance) are necessary to protect against the air pollution levels currently present in North America,3 although it is not known how much vitamin E is needed to produce that protective effect.References
1. Hunt C, Chakravorty NK, Annan G, et al. The clinical effects of vitamin C supplementation in elderly hospitalised patients with acute respiratory infections. Int J Vitam Nutr Res 1994;64:212-9.
2. Hemila H. Does vitamin C alleviate the symptoms of the common cold?-A review of current evidence. Scand J Infect Dis 1994;26:1-6.
3. Menzel DB. Antioxidant vitamins and prevention of lung disease.Ann N Y Acad Sci 1992;669:141-55.Immune FunctionDose: Consult a qualified healthcare practitioner
Most,1, 2 but not all,3 double-blind studies have shown that elderly people have better immune function and reduced infection rates when taking a multiple vitamin-mineral formula. In one double-blind trial, supplements of 100 mcg per day of selenium and 20 mg per day of zinc, with or without additional vitamin C, vitamin E, and beta-carotene, reduced infections in elderly people, though vitamins without minerals had no effect.4 Burn victims have also experienced fewer infections after receiving trace mineral supplements in double-blind research.5 These studies suggest that trace minerals may be the most important micronutrients for enhancing immunity and preventing infections in the elderly.
Vitamin C stimulates the immune system by both elevating interferon levels6 and enhancing the activity of certain immune cells.7, 8 Two studies came to opposite conclusions about the ability of vitamin C to improve immune function in the elderly,9, 10 and two other studies did not agree on whether vitamin C could protect people from hepatitis.11, 12 However, a review of 20 double-blind studies concluded that while several grams of vitamin C per day has only a small effect in preventing colds, when taken at the onset of a cold, it does significantly reduce the duration of a cold.13 In controlled reports studying people doing heavy exercise, cold frequency was reduced an average of 50% with vitamin C supplements ranging from 600 to 1,000 mg per day.14 Thus, the overall effect of vitamin C on immune function is unclear, and its usefulness may vary according to the situation.
A combination of antioxidants vitamin A, vitamin C, and vitamin E significantly improved immune cell number and activity compared with placebo in a group of hospitalized elderly people.15 Daily intake of a 1,000 mg vitamin C plus 200 IU vitamin E for four months improved several measures of immune function in a preliminary study.16 To what extent immune-boosting combinations of antioxidants actually reduce the risk of infection remains unknown.References
1. Pike J, Chandra RK. Effect of vitamin and trace element supplementation on immune indices in healthy elderly. Int J Vitam Nutr Res 1995;65:117-21.
2. Chandra RK. Effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects. Lancet 1992;340:1124-7.
3. Chavance M, Herbeth B, Lemoine A, et al. Does multivitamin supplementation prevent infections in healthy elderly subjects? A controlled trial. Int J Vitam Nutr Res 1993;63:11-6.
4. Girodon F, Lombard M, Galan P, et al. Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial. Ann Nutr Metab 1997;41:98-107.
5. Berger MM, Spertini F, Shenkin A, et al. Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial. Am J Clin Nutr 1998;68:365-71.
6. Gerber WF, Lefkowitz SS, Hung CY. Effect of ascorbic acid, sodium salicylate, and caffeine on the serum interferon level in response to viral infection. Pharmacology 1975;13:228.
7. Anderson R. The immunostimulatory, anti-inflammatory an anti-allergic properties of ascorbate. Adv Nutr Res 1984;6:19-45 [review].
8. Banic S. Immunostimulation by vitamin C. Int J Vitam Nutr Res Suppl 1982;23:49-52 [review].
9. Delafuente JC, Prendergast JM, Modigh A. Immunologic modulation by vitamin C in the elderly. Int J Immunopharmacol 1986;8:205-11.
10. Kennes B, Dumont I, Brohee D, et al. Effect of vitamin C supplements on cell-mediated immunity in old people. Gerontology 1983;29:305-10.
11. Murata A. Virucidal activity of vitamin C for prevention and treatment of viral diseases. In Proceedings of the First Intersectional Congress of IAMS, vol 3. Science Council Japan, 1975, 432.
12. Knodell RG, Tate MA, Akl BF, et al. Vitamin C prophylaxis for posttransfusion hepatitis: Lack of effect in a controlled trial. Am J Clin Nutr 1981;34(1):20-3.
13. Hemila H. Vitamin C and the common cold. Br J Nutr 1992;67:3-16.
14. Hemila H. Vitamin C and common cold incidence: a review of studies with subjects under heavy physical stress. Int J Sports Med 1996;17:379-83.
15. Penn ND, Purkins L, Kelleher J, et al. The effect of dietary supplementation with vitamins A, C and E on cell-mediated immune function in elderly long-stay patients: a randomized controlled trial. Age Ageing 1991;20:169-74.
16. de la Fuente M, Ferrandez MD, Burgos MS, et al. Immune function in aged women is improved by ingestion of vitamins C and E. Can J Physiol Pharmacol 1998;76:373-80.InfluenzaDose: 100 mg daily
Dockworkers given 100 mg of vitamin C each day for ten months caught influenza 28% less often than did their coworkers not taking vitamin C. Of those who did develop the flu, the average duration of illness was 10% less in those taking vitamin C than in those not taking the vitamin.1 Other trials have reported that taking vitamin C in high amounts (2 grams every hour for 12 hours) can lead to rapid improvement of influenza infections.2, 3 Such high amounts, however, should only be used under the supervision of a healthcare professional.References
1. Renker K, Wegner S. Vitamin C-Prophylaxe in der Volkswertf Stralsund. Deutsche Gesundheitswesen 1954;9:702-6.
2. Klenner FR. The treatment of poliomyelitis and other virus diseases with vitamin C. South Med Surg 1949;111:210-4.
3. Pauling L. Vitamin C, the Common Cold and the Flu. San Francisco: W. H. Freeman & Company, 1976 [review].Cold SoresDose: 200 mg with 200 mg flavonoids, three to five times daily
Vitamin C has been shown to inactivate herpes viruses in the test tube.1 In one study, people with herpes infections received either a placebo or 200 mg of vitamin C plus 200 mg of flavonoids, each taken three to five times per day. Compared with the placebo, vitamin C and flavonoids reduced the duration of symptoms by 57%.2References
1. Holden M, Molloy E. Further experiments on the inactivation of herpes virus by vitamin C (l-ascorbic acid). J Immunol 1937;33:251-7.
2. Terezhalmy GT, Bottomley WK, Pelleu GB. The use of water-soluble bioflavonoid-ascorbic acid complex in the treatment of recurrent herpes labialis. Oral Surg 1978;45:56-62.Pre- and Post-Surgery Health and Vitamin C DeficiencyDose: 100 to 250 mg once or twice per day
Vitamin C deficiency can be detrimental to immune function in hospitalized patients,1 and one study found that half of surgery patients recovering at home had low dietary intakes of vitamin C.2 Vitamin C is also a critical nutrient for wound healing,3, 4 but studies of vitamin C supplementation have shown only minor effects on the healing of surgical wounds.5, 6 Vitamin C deficiency also can increase the risk of excessive bleeding in the surgical setting.7References
1. Dowd PS, Kelleher J, Walker BE, Guillou PJ. Nutrition and cellular immunity in hospital patients. Br J Nutr 1986;55:515-27.
2. Stotts NA, Whitney JD. Nutritional intake and status of clients in the home with open surgical wounds. J Community Health Nurs 1990;7:77-86.
3. Thomas DR. Specific nutritional factors in wound healing. Adv Wound Care 1997;10:40-3 [review].
4. Wendt MD, Soparkar CN, Louie K, et al. Ascorbate stimulates type I and type III collagen in human Tenon's fibroblasts. J Glaucoma 1997;6:402-7.
5. Vaxman F, Olender S, Lambert A, et al. Effect of pantothenic acid and ascorbic acid supplementation on human skin wound healing process. A double-blind, prospective and randomized trial. Eur Surg Res 1995;27:158-66.
6. Vaxman F, Olender S, Lambert A, et al. Can the wound healing process be improved by vitamin supplementation? Experimental study on humans. Eur Surg Res 1996;28:306-14.
7. Blee TH, Cogbill TH, Lambert PJ. Hemorrhage associated with vitamin C deficiency in surgical patients. Surgery 2002;131:408-12.SunburnDose: 2,000 to 3,000 mg vitamin C and 1,000 to 2,000 IU vitamin E
Antioxidants may protect the skin from sunburn due to free radical-producing ultraviolet rays.1 Combinations of 1,000 to 2,000 IU per day of vitamin E and 2,000 to 3,000 mg per day of vitamin C, but neither given alone, have a significant protective effect against ultraviolet rays, according to double-blind studies.2, 3, 4
Oral synthetic beta-carotene alone was not found to provide effective protection when given in amounts of 15 mg per day or for only a few weeks' time in larger amounts of 60 to 90 mg per day, but it has been effective either in very large (180 mg per day) amounts or in smaller amounts (30 mg per day) in combination with topical sunscreen.5, 6, 7, 8, 9
Natural sources of beta-carotene or other carotenoids have been more consistently shown to protect against sunburn. One controlled study found that taking a supplement of natural carotenoids (almost all of which was beta-carotene) in daily amounts of 30 mg, 60 mg, and 90 mg gave progressively more protection against ultraviolet rays.10 In another controlled study, either 24 mg per day of natural beta-carotene or 24 mg per day of a carotenoid combination of equal amounts beta-carotene, lutein, and lycopene helped protect skin from ultraviolet rays.11 A preliminary study compared synthetic lycopene (10.1 mg per day), a natural tomato extract containing 9.8 mg of lycopene per day plus additional amounts of other carotenoids, and a solubilized tomato drink (designed to increase lycopene absorption) containing 8.2 mg of lycopene plus additional amounts of other carotenoids. After 12 weeks, only the two tomato-based products were shown to give significant protection against burning by ultraviolet light.12
Still other trials have tested combinations of several antioxidants. One preliminary study found that a daily combination of beta-carotene (6 mg), lycopene (6 mg), vitamin E (15 IU), and selenium for seven weeks protected against ultraviolet light.13 However, a double-blind trial of a combination of smaller amounts of several carotenoids, vitamins C and E, selenium, and proanthocyanidins did not find significant UV protection compared with placebo.14 Similarly, in a controlled trial, a combination of selenium, copper, and vitamins was found to be ineffective.15
It should be noted that while oral protection from sunburn has been demonstrated with several types of antioxidants, the degree of protection (typically less than an SPF of 2) is much less than that provided by currently available topical sunscreens. On the other hand, these modest effects will provide some added protection to skin areas where sunscreen is also used and will give a small amount of protection to sun-exposed areas where sunscreen is not applied. However, oral protection from sunburn is not instantaneous; maximum effects are not reached until these antioxidants have been used for about eight to ten weeks.16, 17References
1. Fuchs J. Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection. Free Radic Biol Med 1998;25:848-73.
2. Werninghaus K, Meydani M, Bhawan J, et al. Evaluation of the photoprotective effect of oral vitamin E supplementation. Arch Dermatol 1994;130:1257-61.
3. Fuchs J, Kern H. Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation. Free Radic Biol Med 1998;25:1006-12.
4. Eberlein-Konig B, Placzek M, Przybilla B. Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). J Am Acad Dermatol 1998;38:45-8.
5. McArdle F, Rhodes LE, Parslew RA, et al. Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin. Am J Clin Nutr 2004;80:1270-5.
6. Garmyn M, Ribaya-Mercado JD, Russel RM, et al. Effect of beta-carotene supplementation on the human sunburn reaction. Exp Dermatol 1995;4:104-11.
7. Wolf C, Steiner A, Honigsmann H, et al. Do oral carotenoids protect human skin against UV erythema, psoralen phototoxicity, and UV-induced DNA damage? J Invest Dermatol 1988;90:55-57.
8. Mathews-Roth MM, Pathak MA, Parrish J, et al. A clinical trial of the effects of oral beta-carotene on the responses of human skin to solar radiation. J Invest Dermatol 1972;59:349-53.
9. Gollnick HP, Hopfenmuller W, Hemmes C, et al. Systemic B-carotene plus topical sunscreen are an optimal protection against harmful effects of natural UV-sunlight. Eur J Dermatol 1996;6:200-5.
10. Lee J, Jiang S, Levine N, Watson RR. Carotenoid supplementation reduces erythema in human skin after simulated solar radiation exposure. Proc Soc Exp Biol Med 2000;223:170-4.
11. Heinrich U, Gartner C, Wiebusch M, et al. Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema. J Nutr 2003;133:98-101.
12. Aust O, Stahl W, Sies H, et al. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema. Int J Vitam Nutr Res 2005;75:54-60.
13. Cesarini JP, Michel L, Maurette JM, et al. Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids. Photodermatol Photoimmunol Photomed 2003;19:182-9.
14. Greul AK, Grundmann JU, Heinrich F, et al. Photoprotection of UV-irradiated human skin: an antioxidative combination of vitamins E and C, carotenoids, selenium and proanthocyanidins. Skin Pharmacol Appl Skin Physiol 2002;15:307-15.
15. La Ruche G, Cesarini JP. Protective effect of oral selenium plus copper associated with vitamin complex on sunburn cell formation in human skin. Photodermatol Photoimmunol Photomed 1991;8:232-5.
16. Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu Rev Nutr 2004;24:173-200 [review].
17. Sies H, Stahl W. Carotenoids and UV protection. Photochem Photobiol Sci 2004;3:749-52 [review].Wound HealingDose: 1 to 3 grams daily
Vitamin C is needed to make collagen (connective tissue) that strengthens skin, muscles, and blood vessels and to ensure proper wound healing. Severe injury appears to increase vitamin C requirements,1 and vitamin C deficiency causes delayed healing.2 Preliminary human studies suggest that vitamin C supplementation in non-deficient people can speed healing of various types of wounds and trauma, including surgery, minor injuries, herniated intervertebral discs, and skin ulcers.3, 4 A combination of 1-3 grams per day of vitamin C and 200-900 mg per day of pantothenic acid has produced minor improvements in the strength of healing skin tissue.5, 6References
1. Levine M. New concepts in the biology and biochemistry of ascorbic acid. N Engl J Med 1986;314:892-902 [review].
2. Mazzotta MY. Nutrition and wound healing. J Am Podiatr Med Assoc 1994;84:456-62 [review].
3. Mazzotta MY. Nutrition and wound healing. J Am Podiatr Med Assoc 1994;84:456-62 [review].
4. Ringsdorf WM Jr, Cheraskin E. Vitamin C and human wound healing. Oral Surg Oral Med Oral Pathol 1982;53:231-6 [review].
5. Vaxman F, Olender S, Lambert A, et al. Can the wound healing process be improved by vitamin supplementation? Experimental study on humans. Eur Surg Res 1996;28:306-14.
6. Vaxman F, Olender S, Lambert A, et al. Effect of pantothenic acid and ascorbic acid supplementation on human skin wound healing process. A double-blind, prospective and randomized trial. Eur Surg Res 1995;27:158-66.SunburnDose: Apply a formula containing 2% vitamin E, 5% vitamin C, and 1% to 2.5% melatonin before sun exposure
Antioxidants have been studied as topical agents for protection against sunburn. Animal studies have found sunscreen-like effects from topical application of a vitamin C and vitamin E combination, and a controlled human study reported ultraviolet protection from the use of a lotion containing 0.02% to 0.05% of the selenium-containing amino acid known as selenomethionine.1, 2 The topical use of the hormone melatonin has been shown to protect human skin against ultraviolet rays in double-blind research.3, 4 A double-blind human trial tested topical vitamins C and E and melatonin, alone and in combinations, and found the highest degrees of protection from combination formulations containing 2% vitamin E, 5% vitamin C, and 1% to 2.5% melatonin.5 Other studies in which topical antioxidants were applied after ultraviolet exposure have found no benefits.6, 7References
1. Lin JY, Selim MA, Shea CR, et al. UV photoprotection by combination topical antioxidants vitamin C and vitamin E. J Am Acad Dermatol 2003;48:866-74.
2. Burke KE, Burford RG, Combs GF Jr, et al. The effect of topical L-selenomethionine on minimal erythema dose of ultraviolet irradiation in humans. Photodermatol Photoimmunol Photomed 1992;9:52-7.
3. Bangha E, Elsner P, Kistler GS. Suppression of UV-induced erythema by topical treatment with melatonin (N-acetyl-5-methoxytryptamine). Influence of the application time point. Dermatology 1997;195:248-52.
4. Bangha E, Elsner P, Kistler GS. Suppression of UV-induced erythema by topical treatment with melatonin (N-acetyl-5-methoxytryptamine). A dose response study. Arch Dermatol Res 1996;288:522-6.
5. Dreher F, Gabard B, Schwindt DA, Maibach HI. Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo. Br J Dermatol 1998;139:332-9.
6. Dreher F, Denig N, Gabard B, et al. Effect of topical antioxidants on UV-induced erythema formation when administered after exposure. Dermatology 1999;198:52-5.
7. Fuchs J. Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection. Free Radic Biol Med 1998;25:848-73 [review].SunburnDose: Apply a formula containing 2% vitamin E and 5% vitamin C before sun exposureSkin UlcersDose: 1,000 mg daily
Antioxidants such as vitamin C, vitamin E, and glutathione are depleted in healing skin tissue.1 One animal study found that vitamin E (alpha-tocopherol) applied to the skin shortened the healing time of skin ulcers.2 Another animal study reported that administration of oral vitamin E before skin lesions were introduced into the skin prevented some of the tissue damage associated with the development of pressure ulcers.3 A controlled human trial found that 400 IU of vitamin E daily improved the results of skin graft surgery for chronic venous ulcers.4 No further research has investigated the potential benefit of vitamin E for skin ulcers.
Animal research has suggested that vitamin C may help prevent skin ulcers,5 and in a preliminary study,6 elderly patients with pressure ulcers had lower blood levels of vitamin C than did ulcer-free patients. Supplementation with vitamin C (3 grams per day) increased the speed of healing of leg ulcers in patients with a blood disorder called thalassemia, according to a double-blind study.7 And while a double-blind trial of surgical patients with pressure ulcers found that supplementation with 500 mg of vitamin C twice a day accelerated ulcer healing,8 a similar double-blind trial found no difference in the effectiveness of either 20 mg per day or 1,000 mg per day of vitamin C.9References
1. Houwing R, Overgoor M, Kon M, et al. Pressure-induced skin lesions in pigs: reperfusion injury and the effects of vitamin E. J WoundCare 2000; 9:36-40.
2. Lucero MJ, Vigo J, Rabasco AM, et al. Protection by alpha-tocopherol against skin necrosis induced by doxorubicin hydrochloride. Pharmazie 1993;48:772-5.
3. Shukla A, Rasik AM, Patnaik GK. Depletion of reduced glutathione, ascorbic acid, vitamin E, and antioxidant defence enzymes in a healing cutaneous wound. Free RadicRes 1997;26:93-101.
4. Ramasastry, SS, Angel MF, Narayanan K, et al. Biochemical evidence of lipoperoxidation in venous stasis ulcer: Beneficial role of vitamin E as antioxidant. Ann NY Acad Sci 1989; 506-8.
5. Hajarizadeh H, Lebredo L, Barrie R, Woltering EA. Protective effect of doxorubicin in vitamin C or dimethyl sulfoxide against skin ulceration in the pig. Ann Surg Oncol 1994;1:411-4.
6. Goode HF, Burns E, Walker BE. Vitamin C depletion and pressure sores in elderly patients with femoral neck fracture. BMJ 1992;305:935-7.
7. Afifi AM, Ellis L, Huntsman RG, Said MI. High dose ascorbic acid in the management of thalassaemia leg ulcers-a pilot study. Br J Dermatol 1975;92:339-41.
8. Taylor TV, Rimmer S, Day B, et al. Ascorbic acid supplementation in the treatment of pressure cores. Lancet 1974;ii:544-6.
9. ter Riet G, Kessels AG, Knipschild PG. Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers. J Clin Epidemiol 1995;48:1453-60.EczemaDose: Refer to label instructions
In 1989, Medical World News reported that researchers from the University of Texas found that vitamin C, at 50-75 mg per 2.2 pounds of body weight, reduced symptoms of eczema in a double-blind trial.1 In theory, vitamin C might be beneficial in treating eczema by affecting the immune system, but further research has yet to investigate any role for this vitamin in people with eczema.ReferencesBoilsDose: Refer to label instructionsProgressive Pigmented PurpuraDose: Refer to label instructionsVitiligoDose: Refer to label instructions
A clinical report describes the use of vitamin supplements in the treatment of vitiligo.1Folic acid and/or vitamin B12 and vitamin C levels were abnormally low in most of the 15 people studied. Supplementation with large amounts of folic acid (1-10 mg per day), along with vitamin C (1 gram per day) and intramuscular vitamin B12 injections (1,000 mcg every two weeks), produced marked repigmentation in eight people. These improvements became apparent after three months, but complete repigmentation required one to two years of continuous supplementation. In another study of people with vitiligo, oral supplementation with folic acid (10 mg per day) and vitamin B12 (2,000 mcg per day), combined with sun exposure, resulted in some repigmentation after three to six months in about half of the participants.2 This combined regimen was more effective than either vitamin supplementation or sun exposure alone.ReferencesHigh CholesterolDose: 1,000 mg dailyVitamin C appears to protect LDL cholesterol from damage.1 In some clinical trials, cholesterol levels have fallen when people with elevated cholesterol supplement with vitamin C.2 Some studies report that decreases in total cholesterol occur specifically in LDL cholesterol.3 Doctors sometimes recommend 1 gram per day of vitamin C. A review of the disparate research concerning vitamin C and heart disease, however, has suggested that most protection against heart disease from vitamin C, is likely to occur with as little as 100 mg per day.4References
1. Frei B. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage. Am J Clin Nutr 1991;54:1113-8S.
2. Simon JA. Vitamin C and cardiovascular disease: a review. J Am Coll Nutr 1992;11:107-27.
3. Gatto LM, Hallen GK, Brown AJ, Samman S. Ascorbic acid induces a favorable lipoprotein profile in women. J Am Coll Nutr 1996;15;154-8.
4. Balz F. Antioxidant Vitamins and Heart Disease. Presented at the 60th Annual Biology Colloquium, Oregon State University, February 25, 1999.Capillary FragilityDose: Treat deficiency with up to 1 gram daily
Severe vitamin C deficiency (scurvy) is a well-recognized but uncommon cause of increased capillary fragility. Whether vitamin C supplementation can help capillary fragility in people who do not have scurvy is less clear. Patients undergoing dialysis may develop low levels of vitamin C,1, 2 which can lead to capillary fragility, but giving dialysis patients 50 mg of vitamin C per day had no effect on capillary fragility in one study.3 People with kidney failure and those undergoing dialysis should not supplement with more than 100 mg per day, unless supervised by a doctor.
According to preliminary studies, vitamin C may reduce capillary weakness in diabetics, who often have low blood levels of vitamin C compared to non-diabetics.4, 5 In a double-blind trial, elderly people with low vitamin C levels and capillary fragility were helped with supplementation of one gram per day of vitamin C.6References
1. Bradley DW, Maynard JE, Webster H. Plasma and whole blood concentrations of ascorbic acid in patients undergoing long-term hemodialysis. Am J Clin Pathol 1973;60:145-7.
2. Sullivan JF, Eisenstein AB. Ascorbic acid depletion during hemodialysis. JAMA 1972;220:1697-9.
3. Tomson CR, Channon SM, Parkinson IS. Correction of subclinical ascorbate deficiency in patients receiving dialysis: effects on plasma oxalate, serum cholesterol, and capillary fragility. Clin Chim Acta 1989;180:255-64.
4. Cox BD, Butterfield WJ. Vitamin C supplements and diabetic cutaneous capillary fragility. Br Med J 1975;3:205.
5. Will JC, Byers T. Does diabetes mellitus increase the requirement for vitamin C? Nutr Rev 1996;54:193-202 [review].
6. Schorah CJ, Tormey WP, Brooks GH, et al. The effect of vitamin C supplements on body weight, serum proteins, and general health of an elderly population. Am J Clin Nutr 1981;34:871-6.AtherosclerosisDose: 250 mg twice per day
Experimentally increasing homocysteine levels in humans has led to temporary dysfunction of the cells lining blood vessels. Researchers are concerned this dysfunction may be linked to atherosclerosis and heart disease. Vitamin C has been reported in one controlled study to reverse the dysfunction caused by increases in homocysteine.1 Vitamin C also protects LDL.2
Despite the protective mechanisms attributed to vitamin C, some research has been unable to link vitamin C intake to protection against heart disease. These negative trials have mostly been conducted using people who consume 90 mg of vitamin C per day or more-a level beyond which further protection of LDL may not occur. Studies of people who eat foods containing lower amounts of vitamin C have been able to show a link between dietary vitamin C and protection from heart disease. Therefore, leading vitamin C researchers have begun to suggest that vitamin C may be important in preventing heart disease, but only up to 100-200 mg of intake per day.3 In a double-blind trial,4 supplementation with 250 mg of timed-release vitamin C twice daily for three years resulted in a 15% reduction in the progression of atherosclerosis, compared with placebo. Many doctors suggest that people take vitamin C-often 1 gram per day-despite the fact that research does not yet support levels higher than 500 mg per day.References
1. Chambers JC, McGregor A, Jean-Marie J, et al. Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia. An effect reversible with vitamin C therapy. Circulation 1999;99:1156-60.
2. Frei B. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage. Am J Clin Nutr 1991;54:1113S-8S.
3. Balz F. Antioxidant Vitamins and Heart Disease. Presented at the 60th Annual Biology Colloquium, Oregon State University, February 25, 1999.
4. Salonen JT, Nyyssonen K, Salonen R, et al. Antioxidant supplementation in atherosclerosis prevention (ASAP) study: a randomized trial of the effect of vitamin E and C on 3-year progression of carotid atherosclerosis. J Intern Med 2000;248:177-86.HypertensionDose: Refer to label instructionsIn a pooled analysis of 29 randomized controlled trials, vitamin C supplementation, as compared with placebo, resulted in statistically significant reductions in systolic (average decrease, 3.84 mm Hg) and diastolic (average decrease, 1.48 mm Hg) blood pressure. Average blood pressure reductions in the studies that included only people with hypertension were 4.85 mm Hg for systolic and 1.67 mm Hg for diastolic blood pressure.1 Thus, vitamin C when given in moderate amounts (such as 500 mg per day), has a modest blood pressure-lowering effect, both in people with high blood pressure and in those with normal blood pressure.ReferencesHeart AttackDose: Refer to label instructionsVitamin C has been reported to protect blood vessels from problems associated with heart attack risk in a variety of ways.1, 2, 3 However, research attempting to link vitamin C directly to protection from heart attacks has been inconsistent.4, 5 The reason for this discrepancy appears related to the amount of vitamin C intake investigated in these studies. True or marginal vitamin C deficiencies do appear to increase the risk of suffering heart attacks.6, 7 However, in trials comparing acceptable (i.e., non-deficient) vitamin C levels to even higher levels, additional vitamin C has not been protective.8 Therefore, though many doctors recommend that people at high risk for heart attack take vitamin C-often 1 gram per day-most evidence currently suggests that consuming as little as 100-200 mg of vitamin C per day from food or supplements may well be sufficient.References
1. Chambers JC, McGergor A, Jean-Marie J, et al. Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia. An effect reversible with vitamin C therapy. Circulation 1999;99:1156-60.
2. Fuller CJ, Grundy SM, Norkus EP, Jialal I. Effect of ascorbate supplementation on low density lipoprotein oxidation in smokers. Atherosclerosis 1996;119:139-50.
3. Rath M, Pauling L. Solution to the puzzle of human cardiovascular disease: Its primary cause is ascorbate deficiency leading to the deposition of lipoprotein (a) and fibrinogen/fibrin in the vascular wall. J Orthomol Med 1992;6:125-34.
4. Manson JE, Stampfer MJ, Willett WC, et al. A prospective study of vitamin C and incidence of coronary heart disease in women. Circulation 1992;85:865 [abstract].
5. Klipstein-Grobusch K, Geleijnse JM, den Breeijen JH, et al. Dietary antioxidants and risk of myocardial infarction in the elderly: the Rotterdam Study. Am J Clin Nutr 1999;69:261-6.
6. Nyyssonen K, Parvianinen MT, Salonen R, et al. Vitamin C deficiency and risk of myocardial infarction: prospective population study of men from eastern Finland. BMJ 1997;314:634-8.
7. Simon JA, Hudes ES, Browner WS. Serum ascorbic acid and cardiovascular disease prevalence in U.S. adults. Epidemiology 1998;9:316-21.
8. Rimm EB, Stampfer MJ, Ascherio A, et al. Vitamin E consumption and the risk of coronary heart disease in men. N Engl J Med 1993;328:1450-6.Chronic Obstructive Pulmonary DiseaseDose: Refer to label instructions
A review of nutrition and lung health reported that people with a higher dietary intake of vitamin C were less likely to be diagnosed with bronchitis.1 As yet, the effects of supplementing with vitamin C in people with COPD have not been studied.ReferencesHeart Attack and Vitamin C DeficiencyDose: 100 to 200 mg daily
Vitamin C has been reported to protect blood vessels from problems associated with heart attack risk in a variety of ways.1, 2, 3 However, research attempting to link vitamin C directly to protection from heart attacks has been inconsistent.4, 5 The reason for this discrepancy appears related to the amount of vitamin C intake investigated in these studies. True or marginal vitamin C deficiencies do appear to increase the risk of suffering heart attacks.6, 7 However, in trials comparing acceptable (i.e., non-deficient) vitamin C levels to even higher levels, additional vitamin C has not been protective.8 Therefore, though many doctors recommend that people at high risk for heart attack take vitamin C-often 1 gram per day-most evidence currently suggests that consuming as little as 100-200 mg of vitamin C per day from food or supplements may well be sufficient.GingivitisDose: 300 mg daily
People who are deficient in vitamin C may be at increased risk for periodontal disease.1 When a group of people with periodontitis who normally consumed only 20-35 mg of vitamin C per day were given an additional 70 mg per day, objective improvement of periodontal tissue occurred in only six weeks.2 It makes sense for people who have a low vitamin C intake (e.g., people who eat few fruits and vegetables) to supplement with vitamin C in order to improve gingival health.References
1. Vaananen MK, Markkanen HA, Tuovinen VJ, et al. Periodontal health related to plasma ascorbic acid. Proc Finn Dent Soc 1993;89:51-9.
2. Aurer-Kozelj J, Kralj-Klobucar N, Buzina R, Bacic M. The effect of ascorbic acid supplementation on periodontal tissue ultrastructure in subjects with progressive periodontitis. Int J Vitam Nutr Res 1982;52:333-41.GingivitisDose: 300 mg of vitamin C, plus 300 mg of flavonoids daily
For people who consume adequate amounts of vitamin C in their diet, several studies have found that supplemental vitamin C has no additional therapeutic effect. Research,3 including double-blind evidence,4 shows that vitamin C fails to significantly reduce gingival inflammation in people who are not vitamin C deficient. In one study, administration of vitamin C plus flavonoids (300 mg per day of each) did improve gingival health in a group of people with gingivitis;5 there was less improvement, however, when vitamin C was given without flavonoids. Preliminary evidence has suggested that flavonoids by themselves may reduce inflammation of the gums.6References
3. Woolfe SN, Kenney EB, Hume WR, Carranza FA Jr. Relationship of ascorbic acid levels of blood and gingival tissue with response to periodontal therapy. J Clin Periodontol 1984;11:159-65.
4. Vogel RI, Lamster IB, Wechsler SA, et al. The effects of megadoses of ascorbic acid on PMN chemotaxis and experimental gingivitis. J Periodontol 1986;57:472-9.
5. El-Ashiry GM, Ringsdorf WM, Cheraskin E. Local and systemic influences in periodontal disease. II. Effect of prophylaxis and natural versus synthetic vitamin C upon gingivitis. J Periodontol 1964;35:250-9.
6. Carvel I, Halperin V. Therapeutic effect of water soluble bioflavonoids in gingival inflammatory conditions. Oral Surg Oral Med Oral Pathol 1961;14:847-55.DysmenorrheaDose: 200 mg niacin daily, 300 mg vitamin C daily, and 60 mg rutin daily througout menstrual cycle; for cramps: 100 mg niacin every two to three hoursThe niacin form of vitamin B3 has been reported to be effective in relieving menstrual cramps in 87% of a group of women taking 200 mg of niacin per day throughout the menstrual cycle. They then took 100 mg every two or three hours while experiencing menstrual cramps. In a follow-up study, this protocol was combined with 300 mg of vitamin C and 60 mg of the flavonoid rutin per day, which resulted in a 90% effectiveness for relieving menstrual cramps. Since these two preliminary studies were published many years ago, no further research has explored the relationship between niacin and dysmenorrhea. Niacin may not be effective unless taken for seven to ten days before the onset of menstrual flow.Pregnancy and Postpartum SupportDose: 100 mg daily
Premature rupture of membranes (PROM) affects 10 to 20% of all pregnancies. It is an important cause of preterm delivery and is associated with increased rates of complications in both the mother and child. In a double-blind study, supplementing with 100 mg of vitamin C per day, beginning in the twentieth week of pregnancy, reduced the incidence of PROM by 74%.1 The women in this study were consuming only about 65 mg of vitamin C per day in their diet, which is less than the RDA of 80 to 85 mg per day for pregnant women.ReferencesEndometriosisDose: 1,000 mg vitamin C and 1,200 IU vitamin E dailyIn a double-blind study of women with pelvic pain presumed to be due to endometriosis, supplementation with vitamin E (1,200 IU per day) and vitamin C (1,000 mg per day) for eight weeks resulted in an improvement of pain in 43% of women, whereas none of the women receiving a placebo reported pain relief.1ReferencesFemale Infertility and Luteal Phase DefectDose: 750 mg daily
In some women, infertility is due to a hormonal abnormality known as luteal phase defect. In this condition, the uterine lining does not develop and mature properly, presumably because of a deficiency of the hormone progesterone. In a study of infertile women with luteal phase defect, supplementation with 750 mg of vitamin C per day for up to six months resulted in a pregnancy rate of 25%, compared with a rate of 11% in an untreated control group, a statistically significant difference.1ReferencesMenopauseDose: Refer to label instructions
In 1964, a preliminary trial reported that 1,200 mg each of vitamin C and the flavonoid hesperidin taken over the course of the day helped relieve hot flashes.1 Although placebo effects are strong in women with hot flashes, other treatments used in that trial failed to act as effectively as the flavonoid/vitamin C combination. Since then, researchers have not explored the effects of flavonoids or vitamin C in women with menopausal symptoms.ReferencesMenorrhagiaDose: Refer to label instructions
Both vitamin C and flavonoids protect capillaries (small blood vessels) from damage. In so doing, they might protect against the blood loss of menorrhagia. In one small study, 88% of women with menorrhagia improved when given 200 mg vitamin C and 200 mg flavonoids three times per day.1 In another study, 70% of women with excessive menstrual bleeding experienced at least a 50% reduction in bleeding after taking a flavonoid product.2 The preparation used in this study contained 90% diosmin and 10% hesperidin and was given in the amount of 1,000 mg per day, beginning five days prior to the expected start of menstruation and continuing until the end of bleeding for three cycles.ReferencesStressDose: 1 to 3 grams daily
Animal studies suggest that supplementing with vitamin C can reduce blood levels of stress-related hormones and other measures of stress.1, 2, 3, 4 Controlled studies of athletes have shown that vitamin C supplementation (1,000 to 1,500 mg per day) can reduce stress hormone levels after intense exercise.5, 6 Surgery patients given 2,000 mg per day of vitamin C during the week before and after surgery had a more rapid return to normal of several stress-related hormones compared with patients not given vitamin C.7 In a double-blind trial, young adults took 3,000 mg per day of vitamin C for two weeks, then were given a psychological stress test involving public speaking and mental arithmetic.8 Compared with a placebo group, those taking vitamin C rated themselves less stressed, scored better on an anxiety questionnaire, had smaller elevations of blood pressure, and returned sooner to lower levels of an adrenal stress hormone following the stress test.References
1. Pardue SL, Thaxton JP, Brake J. Role of ascorbic acid in chicks exposed to high environmental temperature. J Appl Physiol 1985;58:1511-6.
2. Doulas NL, Constantopoulos A, Litsios B. Effect of ascorbic acid on guinea pig adrenal adenylate cyclase activity and plasma cortisol. J Nutr 1987;117:1108-14.
3. Zhou X, Xie M, Niu C, Sun R. The effects of dietary vitamin C on growth, liver vitamin C and serum cortisol in stressed and unstressed juvenile soft-shelled turtles (Pelodiscus sinensis). Comp Biochem Physiol A Mol Integr Physiol 2003;135:263-70.
4. Satterlee DG, Aguilera-Quintana I, Munn BJ, Krautmann BA. Vitamin C amelioration of the adrenal stress response in broiler chickens being prepared for slaughter. Comp Biochem Physiol A 1989;94:569-74.
5. Peters EM, Anderson R, Nieman DC, et al. Vitamin C supplementation attenuates the increases in circulating cortisol, adrenaline and anti-inflammatory polypeptides following ultramarathon running. Int J Sports Med 2001;22:537-43.
6. Peters EM, Anderson R, Theron AJ. Attenuation of increase in circulating cortisol and enhancement of the acute phase protein response in vitamin C-supplemented ultramarathoners. Int J Sports Med 2001;22:120-6.
7. Gromova EG, Sviridova SP, Kushlinskii NE, et al. Regulation of the indices of neuroendocrine status in surgical patients with lung cancer using optimal doses of ascorbic acid. Anesteziol Reanimatol 1990;5:71-4 [in Russian].
8. Brody S, Preut R, Schommer K, Schurmeyer TH. A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress. Psychopharmacology (Berl) 2002;159:319-24.GlaucomaDose: At least 2 grams daily
Several studies have shown that supplementing with vitamin C can significantly reduce elevated intraocular pressure in individuals with glaucoma.1 These studies used at least 2 grams per day of vitamin C; much larger amounts were sometimes given. Higher quantities of vitamin C appeared to be more effective than smaller amounts.
Doctors often suggest that people with glaucoma take vitamin C to "bowel tolerance."2 The bowel-tolerance level is determined by progressively increasing vitamin C intake until loose stools or abdominal pain occurs, and then reducing the amount slightly, to a level that does not cause these symptoms. The bowel tolerance level varies considerably from person to person, usually ranging from about 5 to 20 or more grams per day. Vitamin C does not cure glaucoma and must be used continually to maintain a reduction in intraocular pressure.ReferencesMacular DegenerationDose: Refer to label instructions
Sunlight triggers oxidative damage in the eye, which in turn can cause macular degeneration.1 Because vitamin C functions as an antioxidant, it has the potential to protect against macular degeneration. However, in a double-blind trial, supplementing with 500 mg of vitamin C daily for eight years did not decrease the incidence of macular degeneration in healthy male physicians.2ReferencesCataractsDose: 500 to 1,000 mg daily
The major antioxidants in the lens of the eye are vitamin C3 and glutathione (a molecule composed of three amino acids).4 Vitamin C is needed to activate vitamin E,5 which in turn activates glutathione. Both nutrients are important for healthy vision. People who take multivitamins or any supplements containing vitamins C or E for more than 10 years have been reported to have a 60% lower risk of forming a cataract.6
Vitamin C levels in the eye decrease with age.7 However, supplementing with vitamin C prevents this decrease8 and has been linked to a lower risk of developing cataracts.9, 10 Healthy people are more likely to take vitamin C and vitamin E supplements than those with cataracts according to some,11 but not all,12 studies. Dietary vitamin C intake has not been consistently associated with protection from cataracts.13, 14 Nonetheless, because people who supplement with vitamin C have developed far fewer cataracts in some research,15, 16 doctors often recommend 500 to 1,000 mg of vitamin C supplementation as part of a cataract prevention program. The difference between successful and unsuccessful trials may be tied to the length of time people actually supplement with vitamin C. In one preliminary study, people taking vitamin C for at least ten years showed a dramatic reduction in cataract risk, but those taking vitamin C for less than ten years showed no evidence of protection at all.17References
1. Jacques PF, Chylack LT Jr. Epidemiologic evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention. Am J Clin Nutr 1991;53:352S-5S.
2. Knekt P, Heliovaara M, Rissanen A, et al. Serum antioxidant vitamins and risk of cataract. BMJ 1992;305:1392-4.
3. Taylor A, Jacques PF, Nadler D, et al. Relationship in humans between ascorbic acid consumption and levels of total and reduce ascorbic acid in lens, aqueous humor, and plasma. Curr Eye Res 1991;10:751-9.
4. Reddy VN. Glutathione and its function in the lens-an overview. Exp Eye Res 1990;150:771-8.
5. Packer JE, Slater TF, Wilson RL. Direct observation of a free radical interaction between vitamin E and vitamin C. Nature 1979;278:737-8.
6. Mares-Perlman JA, Lyle BJ, Klein R, et al. Vitamin supplement use and incident cataracts in a population-based study. Arch Ophthalmol 2000;118:1556-63.
7. Taylor A. Cataract: relationship between nutrition and oxidation. J Am Coll Nutr 1993;12:138-46 [review].
8. Taylor A, Jacques PF, Nadler D, et al. Relationship in humans between ascorbic acid consumption and levels of total and reduced ascorbic acid in lens, aqueous humor, and plasma. Curr Eye Res 1991;10:751-9.
9. Jacques PF, Chylack LT Jr. Epidemiologic evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention. Am J Clin Nutr 1991;53:352S-5S.
10. Jacques PF, Chylack LT, McGandy RB, Hartz SC. Antioxidant status in persons with and without senile cataract. Arch Ophthalmol 1988;106:337-40.
11. Robertson JMD, Donner AP, Trevithick JR. Vitamin E intake and risk of cataracts in humans. Ann NY Acad Sci 1989;570:372-82.
12. Seddon JM, Christen WG, Manson JE, et al. The use of vitamin supplements and the risk of cataract among US male physicians. Am J Public Health 1994;84:788-92.
13. Lyle BJ, Mares-Perlman JA, Klein BE, et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol 1999;149:801-9.
14. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of vitamin supplement intake and cataract extraction among U.S. women. Epidemiology 1999;10:679-84.
15. Robertson J McD, Donner AP, Trevithick JR. A possible role for vitamins C and E in cataract prevention. Am J Clin Nutr 1991;53:346S-51S.
16. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. BMJ 1992;305:335-9.
17. Jacques PF, Taylor A, Hankinson SE, et al. Long-term vitamin C supplement use and prevalence of early age-related lens opacities. Am J Clin Nutr 1997;66:911-6.Type 2 DiabetesDose: 500 mg twice per day
As with vitamin E, vitamin C may reduce glycosylation.1 Vitamin C also lowers sorbitol levels in people with diabetes.2 Sorbitol is a sugar that can accumulate inside the cells and damage the eyes, nerves, and kidneys of people with diabetes. Vitamin C may improve glucose tolerance in type 2 diabetes,3, 4, 5although not every study confirms this benefit.6 Vitamin C supplementation (500 mg twice a day for one year) has significantly reduced urinary protein loss in people with diabetes. Urinary protein loss (also called proteinuria) is associated with poor prognosis in diabetes.7 Many doctors suggest that people with diabetes supplement with 1 to 3 grams per day of vitamin C. Higher amounts could be problematic, however. In one person, 4.5 grams per day was reported to increase blood sugar levels.8
One study examined antioxidant supplement intake, including both vitamins E and C, and the incidence of diabetic retinopathy (damage to the eyes caused by diabetes).9 Surprisingly, people with extensive retinopathy had a greater likelihood of having taken vitamin C and vitamin E supplements. The outcome of this trial, however, does not fit with most other published data and might simply reflect the fact that sicker people are more likely to take supplements in hopes of getting better. For the present, most doctors remain relatively unconcerned about the outcome of this isolated report.References
1. Davie SJ, Gould BJ, Yudkin JS. Effect of vitamin C on glycosylation of proteins. Diabetes 1992;41:167-73.
2. Will JC, Tyers T. Does diabetes mellitus increase the requirement for vitamin C? Nutr Rev 1996;54:193-202 [review].
3. Eriksson J, Kohvakka A. Magnesium and ascorbic acid supplementation in diabetes mellitus. Ann Nutr Metab 1995;39:217-23.
4. Paolisso G, Balbi V, Volpe C, et al. Metabolic benefits deriving from chronic vitamin C supplementation in aged non-insulin dependent diabetics. J Am Coll Nutr 1995;14:387-92.
5. Dakhale GN, Chaudhari HV, Shrivastava M. Supplementation of vitamin C reduces blood glucose and improves glycosylated hemoglobin in type 2 diabetes mellitus: a randomized, double-blind study. Adv Pharmacol Sci 2011;2011:195271
6. Will JC, Tyers T. Does diabetes mellitus increase the requirement for vitamin C? Nutr Rev 1996;54:193-202 [review].
7. McAuliffe AV, Brooks BA, Fisher EJ, et al. Administration of ascorbic acid and an aldose reductase inhibitor (tolrestat) in diabetes: effect on urinary albumin excretion. Nephron 1998;80:277-84.
8. Branch DR. High-dose vitamin C supplementation increases plasma glucose. Diabetes Care 1999;22:1218 [letter].
9. Mayer-Davis E, Bell RA, Reboussin BA, et al. Antioxidant nutrient intake and diabetic retinopathy. The San Luis Valley Diabetes Study. Ophthalmology 1998;105:2264-70.Pancreatic InsufficiencyDose: 540 mg dailyThere are few controlled trials of antioxidant supplementation to patients with pancreatitis. One small controlled study of acute pancreatitis patients found that sodium selenite at a dose of 50 micrograms (mcg) daily resulted in decreased levels of a marker of free radical activity, and no patient deaths occurred.1 In a small double-blind trial including recurrent acute and chronic pancreatitis patients, supplements providing daily doses of 600 mcg selenium, 9,000 IU beta-carotene, 540 mg vitamin C, 270 IU vitamin E, and 2,000 mg methionine significantly reduced pain, normalized several blood measure of antioxidant levels and free radical activity, and prevented acute recurrences of pancreatitis.2 These researches later reported that continuing antioxidant treatment in these patients for up to five years or more significantly reduced the total number of days spent in the hospital and resulted in 78% of patients becoming pain-free and 88% returning to work.3References
1. Kulinski B, Buchner M, Schweder R, Nagel R. Acute pancreatitis-a free radical disease. Decrease in fatality with sodium selenite (Na2SeO3) therapy. Z Gesamte Inn Med 1991;46:145-9 [in German].
2. Uden S, Bilton D, Nathan L, et al. Antioxidant therapy for recurrent pancreatitis: placebo-controlled trial. Aliment Pharmacol Ther 1990;4:357-71.
3. McCloy R. Chronic pancreatitis at Manchester, UK. Focus on antioxidant therapy. Digestion 1998;59(suppl 4):36-48 [review].Type 1 DiabetesDose: 500 mg twice per day
People with type 1 diabetes appear to have low vitamin C levels.1 As with vitamin E, vitamin C may reduce glycosylation.2 Vitamin C also lowers sorbitol levels in people with diabetes.3 Sorbitol is a sugar that can accumulate inside the cells and damage the eyes, nerves, and kidneys of people with diabetes. Vitamin C supplementation (500 mg twice a day for one year) has significantly reduced urinary protein loss in people with diabetes. Urinary protein loss (also called proteinuria) is associated with poor prognosis in diabetes.4 Many doctors suggest that people with diabetes supplement with 1 to 3 grams per day of vitamin C. Higher amounts could be problematic, however. In one person, 4.5 grams per day was reported to increase blood sugar levels.5
One study examined antioxidant supplement intake, including both vitamins E and C, and the incidence of diabetic eye damage (retinopathy).6 A surprising finding was that people with extensive retinopathy had a greater likelihood of having taken vitamin C and vitamin E supplements. The outcome of this study, however, does not fit with most other published data and might simply reflect the fact that sicker people are more likely to take supplements in hopes of getting better. For the present, most doctors remain relatively unconcerned about the outcome of this isolated report.References
1. Cunningham JJ, Ellis SL, McVeigh KL, et al. Reduced mononuclear leukocyte ascorbic acid content in adults with insulin-dependent diabetes mellitus consuming adequate dietary vitamin C. Metabolism 1991;40:146-9.
2. Davie SJ, Gould BJ, Yudkin JS. Effect of vitamin C on glycosylation of proteins. Diabetes 1992;41:167-73.
3. Will JC, Tyers T. Does diabetes mellitus increase the requirement for vitamin C? Nutr Rev 1996;54:193-202 [review].
4. McAuliffe AV, Brooks BA, Fisher EJ, et al. Administration of ascorbic acid and an aldose reductase inhibitor (tolrestat) in diabetes: effect on urinary albumin excretion. Nephron 1998;80:277-84.
5. Branch DR. High-dose vitamin C supplementation increases plasma glucose. Diabetes Care 1999;22:1218 [letter].
6. Mayer-Davis E, Bell RA, Reboussin BA, et al. Antioxidant nutrient intake and diabetic retinopathy. The San Luis Valley Diabetes Study. Ophthalmology 1998;105:2264-70.HypoglycemiaDose: Refer to label instructions
Research has shown that supplementing with chromium (200 mcg per day)1 or magnesium (340 mg per day)2 can prevent blood sugar levels from falling excessively in people with hypoglycemia. Niacinamide (vitamin B3) has also been found to be helpful for hypoglycemic people.3 Other nutrients, including vitamin C, vitamin E, zinc, copper, manganese, and vitamin B6, may help control blood sugar levels in diabetics.4 Since there are similarities in the way the body regulates high and low blood sugar levels, these nutrients might be helpful for hypoglycemia as well, although the amounts needed for that purpose are not known.References
1. Anderson RA et al. Chromium supplementation of humans with hypoglycemia. Fed Proc 1984;43:471.
2. Stebbing JB et al. Reactive hypoglycemia and magnesium. Magnesium Bull 1982;2:131-4.
3. Shansky A. Vitamin B3 in the alleviation of hypoglycemia. Drug Cosm Ind 1981;129(4):68-69,104-5.
4. Gaby AR, Wright JV. Nutritional regulation of blood glucose. J Advancement Med 1991;4:57-71.Type 1 DiabetesDose: Refer to label instructionsBecause oxidation damage is believed to play a role in the development of diabetic eye damage (retinopathy), antioxidant nutrients might be protective. One doctor has administered a daily regimen of 500 mcg selenium, 800 IU vitamin E, 10,000 IU vitamin A, and 1,000 mg vitamin C for several years to 20 people with diabetic eye damage (retinopathy). During that time, 19 of the 20 people showed either improvement or no progression of their retinopathy.1 People who wish to supplement with more than 250 mcg of selenium per day should consult a healthcare practitioner.ReferencesType 1 Diabetes and Diabetic RetinopathyDose: Refer to label instructionsBecause oxidation damage is believed to play a role in the development of diabetic eye damage (retinopathy), antioxidant nutrients might be protective. One doctor has administered a daily regimen of 500 mcg selenium, 800 IU vitamin E, 10,000 IU vitamin A, and 1,000 mg vitamin C for several years to 20 people with diabetic eye damage (retinopathy). During that time, 19 of the 20 people showed either improvement or no progression of their retinopathy.1 People who wish to supplement with more than 250 mcg of selenium per day should consult a healthcare practitioner.ReferencesReferencesReferencesAsthmaDose: 1,000 to 1,500 mg daily
Supplementation with 1 gram of vitamin C per day reduces the tendency of the bronchial passages to go into spasm,1 an action that has been confirmed in double-blind research.2 Beneficial effects of short-term vitamin C supplementation (i.e., less than three days) have been observed. In double-blind trials, supplementation with 1,000 to 1,500 mg of vitamin C per day for 2 to 14 days prevented attacks of exercise-induced asthma.3, 4 Two other preliminary trials found that vitamin C supplementation reduced bronchial reactivity to metacholine, a drug that causes bronchial constriction.5, 6 However, other studies,7 including two double-blind trials,8, 9 have failed to corroborate these findings. The only double-blind trial of a long duration found that vitamin C supplementation (1 gram per day for 14 weeks) reduced the severity and frequency of attacks among Nigerian adults with asthma.10 A buffered form of vitamin C (such as sodium ascorbate or calcium ascorbate) may work better for some asthmatics than regular vitamin C (ascorbic acid).11References
1. Zuskin E, Valic F, Bouhuys A. Byssinosis and airway responses due to exposure to textile dust. Lung 1976;154:17-24.
2. Bucca C, Rolla G, Oliva A, Farina J-C. Effect of vitamin C on histamine bronchial responsiveness of patients with allergic rhinitis. Ann Allergy 1990;65:311-4.
3. Schachter EN, Schlesinger A. The attenuation of exercise-induced bronchospasm by ascorbic acid. Ann Allergy 1982;49:146-51.
4. Tecklenburg SL, Mickleborough TD, Fly AD, et al. Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma. Respir Med 2007;Apr 4:Epub ahead of print.
5. Mohsenin V, Dubois AB, Douglas JS. Effect of ascorbic acid on response to methacholine challenge in asthmatic subjects. Am Rev Respir Dis 1983;127:143-7.
6. Zuskin E, Lewis AJ, Bouhuys A. Inhibition of histamine-induced airway constriction by ascorbic acid. J Allergy Clin Immunol 1973;51:218-26.
7. Ting S, Mansfield LE, Yarbrough J. Effects of ascorbic acid on pulmonary functions in mild asthma. J Asthma 1983;20:39-42.
8. Malo JL, Cartier A, Pineau L, et al. Lack of acute effects of ascorbic acid on spirometry and airway responsiveness to histamine in subjects with asthma. J Allergy Clin Immunol 1986;78:1153-8.
9. Kordansky DW, Rosenthal RR, Norman PS. The effect of vitamin C on antigen-induced bronchospasm. J Allergy Clin Immunol 1979;63:61-4.
10. Anah CO, Jarike LN, Baig HA. High dose ascorbic acid in Nigerian asthmatics. Trop Geogr Med 1980;32:132-7.
11. Ruskin SL. Sodium ascorbate in the treatment of allergic disturbances. The role of adrenal cortical hormone-sodium-vitamin C. Am J Dig Dis 1947;14:302-6.Hay FeverDose: Refer to label instructions
Although vitamin C has antihistamine activity, and supplementation, in preliminary research,1, 2 has been reported to help people with hay fever, 2,000 mg of vitamin C per day did not reduce hay fever symptoms in a placebo controlled trial.3 Thus, while some doctors recommend that hay fever sufferers take 1,000-3,000 mg of vitamin C per day, supportive evidence remains weak.References
1. Holmes HM, Alexander W. Hay fever and vitamin C. Science 1942;96:497.
2. Ruskin SL. High dose vitamin C in allergy. Am J Dig Dis 1945;12:281.
3. Fortner BR Jr, Danziger RE, Rabinowitz PS, Nelson HS. The effect of ascorbic acid on cutaneous and nasal response to histamine and allergen. J Allergy Clin Immunol 1982;69:484-8.HivesDose: Refer to label instructions
In theory, high amounts of vitamin C might help people with hives by lowering histamine levels.1 Amounts of at least 2,000 mg daily appear necessary to produce these effects.2 No research trials have yet explored the clinical effects of vitamin C supplementation in people with hives.ReferencesAsthmaDose: Refer to label instructions
There is some evidence that combinations of antioxidants such as vitamin E, vitamin C, and selenium may help improve symptoms of asthma throught to be caused by air pollution.1 In one double-blind study, 46 Dutch bicyclists were randomly assigned to receive a placebo or 100 mg of vitamin E and 500 mg of vitamin C daily for 15 weeks.2 Lung function was measured before and after each training session on 380 different occasions, and ambient ozone concentrations were measured during each training session. After analysis, researchers concluded that bicyclists with the vitamins C and E blunted the adverse effects of ozone on measures of lung function. In another double-blind study, 17 adults (18 to 39 years old) were randomly assigned to receive either 400 IU per day of vitamin E and 500 mg per day of vitamin C or a placebo for five weeks.3 Tests showing improved measures of lung function led researchers to conclude that supplementation with vitamins C and E inhibited the decline in pulmonary function induced in asthmatics by exposure to air pollutants. Also using a double-blind design, another study of 158 children with asthma living in Mexico City were randomly assigned to receive, a daily supplement containing 50 mg of vitamin E and 250 mg of vitamin C or a placebo.4 Tests results suggested that supplementing with vitamins C and E may reduce the adverse effect of ozone exposure on lung function of children with moderate to severe asthma.References
1. Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proc Natl Acad Sci 1993;90:7915-22.
2. Grievink L, Zijlstra AG, Ke X, Brunekreef B. Double-blind intervention trial on modulation of ozone effects on pulmonary function by antioxidant supplements. Am J Epidemiol 1999;149:306-14.
3. Trenga CA, Koenig JQ, Williams PV. Dietary antioxidants and ozone-induced bronchial hyperresponsiveness in adults with asthma. Arch Environ Health 2001;56:242-9.
4. Romieu I, Sienra-Monge JJ, Ramirez-Aguilar M, Tellez-Rojo MM, Moreno-Macias H, Reyes-Ruiz NI, et al. Antioxidant supplementation and lung functions among children with asthma exposed to high levels of air pollutants. Am J Respir Crit Care Med 2002;166:703-9.GastritisDose: 5 grams daily
When H. pylori causes gastritis, free radical levels rise in the stomach lining.1 These unstable molecules contribute to inflammation and damage to the stomach lining. Vitamin C, an antioxidant that helps quench free radical molecules, is low in the stomach juice of people with chronic gastritis. This deficiency may be the link between chronic gastritis and the increased risk of stomach cancer. When people with gastritis took 500 mg of vitamin C twice a day, vitamin C levels in their gastric juice rose, though not to normal levels.2 In another trial, vitamin C supplementation (5 grams per day divided into several doses for four weeks) appeared to eliminate H. pylori infection.3 While no direct evidence proves that taking vitamin C reduces gastritis symptoms, scientists widely believe that any agent capable of knocking out H. pylori should help people with this condition.References
1. Drake IM, Mapstone NP, Schorah CJ, et al. Reactive oxygen species activity and lipid peroxidation in Helicobacter pylori associated gastritis: relation to gastric mucosal ascorbic acid concentrations and effect of H pylori eradication. Gut 1998;42(6):768-71.
2. Waring AJ, Drake IM, Schorah CJ, et al. Ascorbic acid and total vitamin C concentrations in plasma, gastric juice, and gastrointestinal mucosa: effects of gastritis and oral supplementation. Gut 1996;38(2):171-6.
3. Jarosz M, Dzieniszewski J, Dabrowska-Ufniarz E, et al. Effects of high dose vitamin C treatment on Helicobacter pylori infection and total vitamin C concentration in gastric juice. Eur J Cancer Prev 1998;7:449-54.Peptic UlcerDose: Refer to label instructions
Little is known about the effects of vitamin C supplementation for people with peptic ulcer. People with gastritis, a related condition, have been found to have low levels of vitamin C in their stomach juice. Vitamin C may also help eradicate H. pylori in people with gastritis. Vitamin C may one day prove to have a therapeutic effect for people with peptic ulcer; however, further research in this area is needed.1ReferencesGallstonesDose: Refer to label instructions
Vitamin C is needed to convert cholesterol to bile acids. In theory, such a conversion should reduce gallstone risks. Women who have higher blood levels of vitamin C have a reduced risk of gallstones.1 Although this does not prove that vitamin C supplements can prevent or treat gallstones, some researchers believe this is plausible.2 One study reported that people who drink alcohol and take vitamin C supplements have only half the risk of gallstones compared with other drinkers, though the apparent protective effect of vitamin C did not appear in non-drinkers.3 In another trial, supplementation with vitamin C (500 mg taken four times per day for two weeks before gallbladder surgery) led to improvement in one parameter of gallstone risk ("nucleation time"), though there was no change in the relative level of cholesterol found in bile.4 While many doctors recommend vitamin C supplementation to people with a history of gallstones, supportive evidence remains preliminary.References
1. Simon JA, Hudes ES. Serum ascorbic acid and gallbladder disease prevalence among US adults. Arch Intern Med 2000;160:931-6.
2. Simon JA. Ascorbic acid and cholesterol gallstones. Med Hypotheses 1993;40:81-4.
3. Simon JA, Grady D, Snabes MC, et al. Ascorbic acid supplement use and the prevalence of gallbladder disease. J Clin Epidemiol 1998;51:257-65.
4. Gustafsson U, Wang F-H, Axelson M, et al. The effect of vitamin C in high doses on plasma and biliary lipid composition in patients with cholesterol gallstones: prolongation of the nucleation time. Eur J Clin Invest 1997;27:387-91.Morning SicknessDose: Refer to label instructions
Vitamin K and vitamin C, taken together, may provide relief of symptoms for some women. In one study, 91% of women who took 5 mg of vitamin K and 25 mg of vitamin C per day reported the complete disappearance of morning sickness within three days.1 Menadione was removed from the market a number of years ago because of concerns about potential toxicity. Although some doctors still use a combination of vitamin K1 (the most prevalent form of vitamin K in food) and vitamin C for morning sickness, no studies on this treatment have been done.ReferencesGoutDose: 0.5 to 8 grams daily
In one small study, people who took 4 grams of vitamin C (but not lower amounts) had an increase in urinary excretion of uric acid within a few hours, and those who took 8 grams of vitamin C per day for several days had a reduction in serum uric acid levels.1 Thus, supplemental vitamin C could, in theory, reduce the risk of gout attacks. However, the authors of this study warned that taking large amounts of vitamin C could also trigger an acute attack of gout by abruptly changing uric acid levels in the body. Another study showed that taking lower amounts of vitamin C (500 mg per day) for two months significantly reduced blood levels of uric acid, especially in people whose initial uric acid levels were elevated.2 For people with a history of gout attacks, it seems reasonable to begin vitamin C supplementation at 500 mg per day, and to increase the amount gradually if uric acid levels do not decrease.References
1. Stein HB, Hasan A, Fox IH. Ascorbic acid-induced uricosuria: a consequence of megavitamin therapy. Ann Intern Med 1976;84:385-8.
2. Huang HY, Appel LJ, Choi MJ, et al. The effects of vitamin C supplementation on serum concentrations of uric acid: results of a randomized controlled trial. Arthritis Rheum 2005;52:1843-7.Low Back PainDose: Refer to label instructions
A preliminary report in 1964 suggested that 500-1,000 mg per day of vitamin C helped many people avoid surgery for their disc-related low back pain.1 No controlled research has been done to examine this claim further.ReferencesUrinary Tract InfectionDose: Refer to label instructions
Many doctors recommend 5,000 mg or more of vitamin C per day for an acute UTI, as well as long-term supplementation for people who are prone to recurrent UTIs. Vitamin C has been shown to inhibit the growth of E. coli, the most common bacterial cause of UTIs.1 In addition, supplementation with 4,000 mg or more of vitamin C per day, results in a slight increase in the acidity of the urine,2 creating an "unfriendly" environment for some infection-causing bacteria. In one controlled trial, pregnant women who supplemented with 100 mg of vitamin C per day experienced 56% less UTI frequency, compared with a placebo.3References
1. Sirsi M. Antimicrobial action of vitamin C on M. tuberculosis and some other pathogenic organisms. Indian J Med Sci 1952;6:252-5.
2. Axelrod DR. Ascorbic acid and urinary pH. JAMA 1985;254:1310-1.
3. Ochoa-Brust GJ, Fernandez AR, Villanueva-Ruiz GJ, et al. Daily intake of 100 mg ascorbic acid as urinary tract infection prophylactic agent during pregnancy. Acta Obstet Gynecol Scand 2007;86:783-7.ReferencesAutismDose: 1 gram per 20 lbs (9 kg) body weight per day
In one double-blind trial lasting ten weeks, autistic children given 1 gram vitamin C per day for each 20 pounds of body weight showed a reduction in symptom severity compared with placebo.1 The authors speculate that vitamin C may play a positive role because of its known effects on a hormone pathway typically disturbed in children with autism.ReferencesChildhood DiseasesDose: Refer to label instructions
Vitamin C has been demonstrated in test tube, animal, and human studies to have immune-enhancing and direct antiviral properties.1 Preliminary observations made on the effect of vitamin C on viral infections have involved both measles and chicken pox.2 An active immune system uses vitamin C rapidly, and blood levels fall in children with bacterial or viral infections.3 Reduced immune cell activity has been observed in people with measles, but in one preliminary study, supplementation with 250 mg daily of vitamin C in children 18 months to 3 years old had no impact on the course of the illness.4 The authors of this study admit that this amount of vitamin C may have been too low to bring about an observable increase in immune cell activity and thus an increase in speed of recovery.References
1. Jariwalla RJ, Harakeh S. Antiviral and immunomodulatory activities of ascorbic acid. Subcell Biochem 1996;25:213-31 [review].
2. Stone I. The Healing Factor: Vitamin C Against Disease. New York: Perigee Books, 1972, 75.
3. Tanzer F, Ozalp I. Leucocyte ascorbic acid concentration and plasma ascorbic acid levels in children with various infections. Mater Med Pol 1993;25:5-8.
4. Joffe MI, Sukha NR, Rabson AR. Lymphocyte subsets in measles. Depressed helper/inducer subpopulation reversed by in vitro treatment with levamisole and ascorbic acid. J Clin Invest 1983;72:971-80.Ear InfectionsDose: Refer to label instructions
Vitamin C supplementation has been reported to stimulate immune function.1, 2 As a result, some doctors recommend between 500 mg and 1,000 mg of vitamin C per day for people with ear infections. Nonetheless, vitamin C supplementation has not been studied by itself in people with ear infections.ReferencesReferencesReferencesSchizophreniaDose: Consult a qualified healthcare practitioner
Up to 6 grams daily of vitamin C has been reported to be beneficial for people with schizophrenia;1, 2 in one case the addition of 400 IU daily of vitamin E enhanced this benefit.3 A small preliminary trial using 8 grams daily of vitamin C showed decreases in hallucinations, suspiciousness, and unusual and disorganized thoughts in 77% of schizophrenic patients.4 In all reported cases, patients were also being treated with sychiatric medications. Some early studies found no difference between blood and urine vitamin C levels in schizophrenics and non-schizophrenics, either before or after supplementation.5, 6, 7 However, later studies found that blood and urine levels of vitamin C were lower in schizophrenics than in non-schizophrenics before and after a single 1,000 mg "load" of vitamin C was taken. After four weeks of daily supplementation with 1,000 mg of vitamin C, blood levels became the same, but urinary levels remained lower in the schizophrenic group, leading the researchers to conclude that the amount of vitamin C required by people with schizophrenia may be greater than that of the general population.8, 9References
1. Sandyk R, Kanofsky JD. Vitamin C in the treatment of schizophrenia. Int J Neurosci 1993;68:67-71.
2. Kanofsky JD, Sandyk R. Antioxidants in the treatment of schizophrenia. Int J Neurosci 1992;62:97-100 [letter].
3. Kanofsky JD, Sandyk R. Antioxidants in the treatment of schizophrenia. Int J Neurosci 1992;62:97-100 [letter].
4. Beauclair L, Vinogradov S, Riney SJ, et al. An adjunctive role for ascorbic acid in the treatment of schizophrenia? J Clin Psychopharmacol 1987;7:282-3 [letter].
5. Pitt B, Pollitt N. Ascorbic acid and chronic schizophrenia. Br J Psychiatry 1971;118:227-8.
6. Grant FW, Cowen MA, Ozerengin MF, Bigelow N. Nutritional requirements in mental illness. I. Ascorbic acid retention in schizophrenia. A reexamination. Biol Psychiatry 1973;5:289-94.
7. Pitt B. Vitamin C and schizophrenia. Lancet 1974;2:1153-4 [letter].
8. Suboticanec K, Folnegovic-Smalc V, Turcin R, et al. Plasma levels and urinary vitamin C excretion in schizophrenic patients. Hum Nutr Clin Nutr 1986;40:421-8.
9. Suboticanec K, Folnegovic-Smalc V, Korbar M, et al. Vitamin C status in chronic schizophrenia. Biol Psychiatry 1990;28:959-66.Age-Related Cognitive DeclineDose: Refer to label instructions
Use of vitamin C or vitamin E supplements, or both, has been associated with better cognitive function and a reduced risk of certain forms of dementia (not including Alzheimer's disease).1 Clinical trials of these antioxidants are needed to confirm the possible benefits suggested by this study.ReferencesBipolar DisorderDose: Refer to label instructions
Vitamin C helps the body to reduce its load of vanadium and this has been studied for its possible role in treatment of bipolar disorder.1 A double-blind trial found that both manic and depressed bipolar patients were significantly improved after one-time administration of 3 grams of vitamin C, compared with a placebo.2 The same study found that both manic and depressed patients did better on a reduced-vanadium diet compared to a normal diet. Another double-blind study reported that 4 grams per day of vitamin C in combination with a drug known as EDTA (which also helps remove elements such as vanadium from the body) was helpful to depressed bipolar patients but not to those experiencing mania.3 Until more is known, people with bipolar illness should avoid supplements containing vanadium and consider supplementing with vitamin C.References
1. Naylor GJ. Vanadium and manic depressive psychosis. Nutr Health 1984;3:79-85 [review].
2. Naylor GJ, Smith AH. Vanadium: a possible aetiological factor in manic depressive illness. Psychol Med 1981;11:249-56.
3. Kay DS, Naylor GJ, Smith AH, Greenwood C. The therapeutic effect of ascorbic acid and EDTA in manic-depressive psychosis: double-blind comparisons with standard treatments. Psychol Med 1984;14:533-9.Athletic Performance and Reducing Pain and Speeding Muscle Strength Recovery after Intense ExerciseDose: 400 mg daily for several days before and after intense exercise
Most research has demonstrated that strenuous exercise increases production of harmful substances called free radicals, which can damage muscle tissue and result in inflammation and muscle soreness. Exercising in cities or smoggy areas also increases exposure to free radicals. Antioxidants, including vitamin C and vitamin E, neutralize free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Regular exercise increases the efficiency of the antioxidant defense system, potentially reducing the amount of supplemental antioxidants that might otherwise be needed for protection. However, at least theoretically, supplements of antioxidant vitamins may be beneficial for older or untrained people or athletes who are undertaking an especially vigorous training protocol or athletic event.1, 2
Placebo-controlled research, some of it double-blind, has shown that taking 400 to 3,000 mg of vitamin C per day for several days before and after intense exercise may reduce pain and speed up muscle strength recovery.3, 4, 5 However, taking vitamin C only after such exercise was not effective in another double-blind study.6 While some research has reported that vitamin E supplementation in the amount of 800 to 1,200 IU per day reduces biochemical measures of free radical activity and muscle damage caused by strenuous exercise,7, 8, 9 several studies have not found such benefits,10, 11, 12, 13 and no research has investigated the effect of vitamin E on performance-related measures of strenuous exercise recovery. A combination of 90 mg per day of coenzyme Q10 and a very small amount of vitamin E did not produce any protective effects for marathon runners in one double-blind trial,14 while in another double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.15
In most well-controlled studies, exercise performance has not been shown to improve following supplementation with vitamin C, unless a deficiency exists, as might occur in athletes with unhealthy or irrational eating patterns.16, 17 Similarly, vitamin E has not benefited exercise performance, 18, 19 except possibly at high altitudes. 20, 21References
1. Kanter M. Free radicals, exercise and antioxidant supplementation. Proc Nutr Soc 1998;57:9-13 [review].
2. Dekkers JC, Van Doornen LJ, Kemper HC. The role of antioxidant vitamins and enzymes in the prevention of exercise-induced muscle damage. Sports Med 1996;21(3):213-38 [review].
3. Jakeman P, Maxwell S. Effect of antioxidant vitamin supplementation on muscle function after eccentric exercise. Eur J Appl Physiol 1993;67:426-30.
4. Kaminski M, Boal R. An effect of ascorbic acid on delayed-onset muscle soreness. Pain 1992;50:317-21.
5. Thompson D, Williams C, McGregor SJ, et al. Prolonged vitamin C supplementation and recovery from demanding exercise. Int J Sport Nutr Exerc Metab 2001;11:466-81.
6. Thompson D, Williams C, Garcia-Roves P, et al. Post-exercise vitamin C supplementation and recovery from demanding exercise. Eur J Appl Physiol 2003;89:393-400.
7. Itoh H, Ohkuwa T, Yamazaki Y, et al. Vitamin E supplementation attenuates leakage of enzymes following 6 successive days of running training. Int J Sports Med 2000;21:369-74.
8. McBride JM, Kraemer WJ, Triplett-McBride T, Sebastianelli W. Effect of resistance exercise on free radical production. Med Sci Sports Exerc 1998;30:67-72.
9. Evans WJ. Vitamin E, vitamin C, and exercise. Am J Clin Nutr 2000;72:647S-52S [review].
10. Dawson B, Henry GJ, Goodman C, et al. Effect of Vitamin C and E supplementation on biochemical and ultrastructural indices of muscle damage after a 21 km run. Int J Sports Med 2002;23:10-15.
11. Beaton LJ, Allan DA, Tarnopolsky MA, et al. Contraction-induced muscle damage is unaffected by vitamin E supplementation. Med Sci Sports Exerc 2002;34:798-805.
12. Petersen EW, Ostrowski K, Ibfelt T, et al. Effect of vitamin supplementation on cytokine response and on muscle damage after strenuous exercise. Am J Physiol Cell Physiol 2001;280:C1570-5.
13. Kanter MM, Nolte LA, Holloszy JO. Effects of an antioxidant vitamin mixture on lipid peroxidation at rest and postexercise. J Appl Physiol 1993;74:965-9.
14. Kaikkonen J, Kosonen L, Nyyssonen K, et al. Effect of combined coenzyme Q10 and d-alpha-tocopheryl acetate supplementaion on exercise-induced lipid peroxidation and muscular damage: a placebo-controlled double-blind study in marathon runners. Free Radic Res 1998;29:85-92.
15. Singh A, Failla ML, Deuster PA. Exercise-induced changes in immune function: effects of zinc supplementation. J Appl Physiol 1994;76:2298-303.
16. Johnston CS, Swan PD, Corte C. Substrate utilization and work efficiency during submaximal exercise in vitamin C depleted-repleted adults. Int J Vitam Nutr Res 1999;69:41-4.
17. Gerster H. The role of vitamin C in athletic performance. J Am Coll Nutr 1989;8:636-43 [review].
18. Tiidus PM, Houston ME. Vitamin E status and response to exercise training. Sports Med 1995;20:12-23 [review].
19. Akova B, Surmen-Gur E, Gur H, et al. Exercise-induced oxidative stress and muscle performance in healthy women: role of vitamin E supplementation and endogenous oestradiol. Eur J Appl Physiol 2001;84:141-7.
20. Simon-Schnass I, Pabst H. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58:49-54.
21. Shepard RJ. Vitamin E and athletic performance. J Sports Med 1983;23:461-70 [review].Athletic Performance and Vitamin C DeficiencyDose: If deficient: 100 to 200 mg daily
9. Evans WJ. Vitamin E, vitamin C, and exercise. Am J Clin Nutr 2000;72:647S-52S [review].
17. Gerster H. The role of vitamin C in athletic performance. J Am Coll Nutr 1989;8:636-43 [review].
21. Shepard RJ. Vitamin E and athletic performance. J Sports Med 1983;23:461-70 [review].Male Infertility and Sperm AgglutinationDose: 1,000 mg daily
Vitamin C protects sperm from oxidative damage.1 Supplementing vitamin C improves the quality of sperm in smokers.2 When sperm stick together (a condition called agglutination), fertility is reduced. Vitamin C reduces sperm agglutination,3 and supplementation with 200-1,000 mg per day increased the fertility of men with this condition in a controlled study.4, 5 Many doctors recommend 1 gram of vitamin C per day for infertile men, particularly those diagnosed with sperm agglutination. However, a double-blind trial studying the effects of combined vitamin C and vitamin E supplementation found no improvements in semen quality among men with low sperm motility.6References
1. Fraga CG, Motchnik PA, Shigenaga MK, et al. Ascorbic acid protects against endogenous oxidative DNA damage in human sperm. Proc Natl Acad Sci 1991;88:11003-6.
2. Dawson EB, Harris WA, Teter MC, Powell LC. Effect of ascorbic acid supplementation on the sperm quality of smokers. Fertil Steril 1992;58:1034-9.
3. Dawson EB, Harris WA, McGanity WJ. Effect of ascorbic acid on sperm fertility. Fed Proc 1983;42:531 [abstr 31403].
4. Dawson EB, Harris WA, Powell LC. Relationship between ascorbic acid and male fertility. In: Aspects of Some Vitamins, Minerals and Enzymes in Health and Disease, ed. GH Bourne. World Rev Nutr Diet 1990;62:1-26 [review].
5. Dawson EB, Harris WA, Rankin WE, et al. Effect of ascorbic acid on male fertility. Ann N Y Acad Sci 1987;498:312-23.
6. Rolf C, Cooper TG, Yeung CH, Nieschlag E. Antioxidant treatment of patients with asthenozoospermia or moderate oligoasthenozoospermia with high-dose vitamin C and vitamin E: a randomized, placebo-controlled, double-blind study. Hum Reprod 1999;14:1028-33.AmenorrheaDose: Refer to label instructionsVitamin C alone, at 400 mg daily, had no effect on amenorrhea in one preliminary trial, although it was associated with the return of ovulation in some women who were menstruating regularly but not ovulating. In a second phase of the trial, the same amount of vitamin C was combined with a drug that affects female hormone levels, and this combination was associated with return of ovulation in almost half of amenorrheic women who had not benefited from the drug alone.1 More studies of the effect of vitamin C on amenorrhea are needed.ReferencesReferences
Vitamin C is a water-soluble vitamin that has a number of biological functions.
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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