Low Choline Increases Risk of Birth Defects

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The infants of pregnant women who have low choline levels are at greater risk of certain birth defects, according to a new study from the Stanford University School of Medicine. Two types of neural tube birth defects - anencephaly and spina bifida - have been linked to insufficient levels of the nutrient.

Spina bifida is a malformation of the spinal cord that can result in various complications, including leg paralysis, spine curvature (scoliosis), problems with bladder and bowel control, and deformities of the hip, feet, and legs. According to the March of Dimes, the birth defect occurs in one in 2,000 births in the United States. Anencephaly is a fatal condition in which the brain and skull do not develop in the womb. It occurs in one in 8,000 births.

During early pregnancy, a sealed tube forma long the embryo’s back. This tube eventually develops into the brain and spinal cord. In some cases, the tube does not seal correctly, resulting in neural tube defects. Previous research showed that folic acid plays a significant role in neural tube development, which prompted the government’s move in 1996 to fortify the US food supply with folic acid. Now it appears that choline has a role as well.

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In the Stanford study, the researchers evaluated 180,000 blood samples taken from the same number of pregnant women. The samples were collected between the 15th and 18th week of pregnancy, which is after formation of the neural tube. Of the 180,000 women, 80 had an infant with a neural tube defect. The blood samples of these women were compared with 409 randomly selected samples from women whose infants did not have structural birth defects.

The investigators found that choline was the only nutrient associated with a risk of neural tube defects. The risk for having an infant with a neural tube defect was 2.4 times greater in women who had the lowest blood levels of choline, compared to women who had average choline levels. An earlier study had shown that consuming choline-rich foods was associated with a lower risk for neural tube defects, but this was the first study to evaluate blood levels of choline and the risk of these birth defects.

For now it remains for researchers to evaluate blood choline levels closer to the time that the neural tube seals, which is around the sixth week of pregnancy. Studies also need to be done on whether choline supplements taken during early pregnancy can reduce the rates of neural tube defects.

Although there is no Recommended Daily Intake (DRI) for choline, the recommended Adequate Intake is 550 mg for men and 425 mg for women. It is still too early to know whether choline supplements can reduce the erisk of neural tube defects. Women who are contemplating pregnancy should take the recommended prenatal vitamins (which typically contain little or no choline) and eat foods rich in choline, such as wheat germ, soy, egg yolks, peanuts, lentils, potatoes, and oats.

SOURCES:
March of Dimes
Fischer LM et al. Am J Clin Nutr 2007; 85:1275-85
Stanford University School of Medicine, 8/12/09: “Low choline levels in pregnant women raise babies’ risk for brain and spinal-cord defects, study shows”

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