Seeking safe cramp relief

Magnesium is a "macromineral," meaning that our bodies require large amounts of it in the diet in order for our bodies to function properly. Magnesium is involved with bone formation, the activation of B-vitamins, blood pressure regulation, muscle relaxation, blood clotting, and insulin production. Some studies have shown that magnesium might help relieve cramps, but not all of the results have been so promising.

A study conducted in Thailand investigated the effect of magnesium on the frequency and severity of leg cramps in 80 healthy pregnant women who experienced cramps at least two times per week. The women were given 300 mg of magnesium (as magnesium bisglycinate) or placebo every day for four weeks. They recorded their symptoms before and after the trial.By the end of the study, leg cramps were:

• less frequent by one half in 86% of the women in the magnesium group compared with 61% of the women in the placebo group, and
• less intense by one half in 70% of the women in the magnesium group compared with 49% of the women in the placebo group.

There were no significant differences between the groups in terms of side effects, including nausea and diarrhea.

How much magnesium do you need?

Most pregnant women need about 350 mg of magnesium per day. Magnesium supplements seem to be safe for most pregnant women to take, but too much magnesium can cause problems, especially diarrhea.

You're not likely to overdose on magnesium from dietary sources. Some terrific food sources of magnesium include pumpkin seeds, Swiss chard, spinach, mustard greens, soybeans, sesame seeds, black beans, sunflower seeds, cashews, and almonds.

Talk with your obstetrician about how much magnesium is right for you.

"I usually discuss my patients' diets with them to assess adequate calcium, magnesium, and potassium intake," explains Michelle Palmer, a certified nurse midwife in RI. "I like to ask about what they eat instead of how many milligrams of each nutrient they're getting or taking as a supplement. If they're eating oranges, bananas, beans, tahini, green vegetables, and dairy regularly, I can be pretty sure that their intake of those minerals is adequate."

(Matern Child Nutr 2012; DOI:10.1111/j.1740-8709.2012.00440.x)