Various Minerals and Pyridoxine May Help Prevent Gestational Diabetes

Reference: Jovanovic-Peterson L, Peterson CM. Vitamin and mineral deficiencies which may predispose to glucose intolerance of pregnancy. J Am Coll Nutr 1996; 15(1):14-20.

Summary: Pregnancy is a state of insulin resistance. This state is important to ensure adequate blood glucose to the growing fetus, but it places an extra burden on the pancreas of the mother. Perhaps the best explanation for the high potential to develop diabetes during pregnancy (gestational diabetes) is the "diabetogenic" nature of a number of the hormones which rise during pregnancy. The rise of estradiol, prolactin and human chorionic somatomammotropin within the first month and a half of pregnancy have a weak to moderate diabetogenic effect, whereas hormones which begin to rise later in pregnancy such as cortisol and progesterone have the strongest diabetogenic potential. Because several of these hormones have a peak elevation around 26 weeks this is considered the optimum time in which to screen for gestational diabetes.

Four micronutrients may be especially helpful in preventing or treating gestational diabetes. Accumulated evidence suggests that a glucose intolerance or insulin resistant state can develop with chromium deficiency. A number of studies have found a deficiency in hair chromium in pregnant women compared to nonpregnant women. The authors randomized 24 women with gestational diabetes to receive either chromium picolinate (4 mcg/kg) or placebo for eight weeks. The women receiving the chromium had signficantly lower fasting glucose and insulin levels and significantly lower peak glucose and insulin in response to a 100 g oral glucose load compared to the placebo group.

Serum magnesium has been inversely correlated with the degree of hyperglycemia in diabetic patients. Magnesium defiency can lead to an intracelIular depletion of potassium because it impairs the activity of the sodium/potassium ATPase pump. An intracellular pancreatic depletion of potassium can lead to a decreased release of insulin. Refractory potassium depletion may respond to magnesium supplementation.

At least one study has found that vitamin B6 supplementation can improve glucose tolerance in women with gestational diabetes. The authors state that it is important not to supplement vitamin B6 until the second trimester, a time when prolactin has reached a sufficient blood level so that supplemental vitamin B6 will not severely suppress prolactin secretion.

Comments/Opinions: This review paper brings together compelling data suggesting a role for mineral and possibly vitamin B6 supplementation as a way to treat gestational diabetes. Pregnant women may be especially vulnerable to chromium, magnesium and potassium deficiencies. The intakes of these three minerals tend to be low in people eating the standard American diet and for some reason chromium and magnesium levels tend to be low in pregnant women. Furthermore, the standard iron supplementation given to pregnant women can impair intestinal absorption of magnesium and chromium.

The minerals described in this paper are not considered standard supplements to give to pregnant women, yet there is evidence that they may be crucial in helping to prevent gestational diabetes and its subsequent detrimental effects on both mother and fetus. It may be that during pregnancy the requirement for these minerals is greater, but not currently recognized. It appears that the most appropriate course of action at this time is to supplement the pregnant woman with 200 mcg of chromium, 500 mg of magnesium and recommend a diet high in fruit and vegetables and low in packaged foods to ensure adequate potassium intake. In order to maintain a balance between magnesium and calcium, the following guidelines may be used: if supplementing 500 mg of magnesium, recommend 1000 mg of calcium. Interestingly, magnesium supplementation is a well established treatment for pregnancy-induced hypertension.

The authors are concerned that supplementation of vitamin B6 too early in the pregnancy might actually inhibit the normal rise of prolactin. It is unclear how concerned a practitioner needs to be about this possibility since vitamin B6 is a typical part of every prenatal vitamin supplement on the market. It is possible that it's not a problem in multivitamin formulas. For now, it may be wise to not supplement with vitamin B6 individually before the second trimester until more is known about its interaction with prolactin.

Natural Product Research Consultants, Inc.


By A. MacIntosh

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