Vitamin B12 Deficiency Can Lead to Childhood Brain Damage

Whether you like them raw on the half shell or cooked in your clam chowder, three ounces of these mollusks boast 84.1 μg of Vitamin B12. A king of the superfoods, clams are also a top source of potassium and the No. 1 source of iron.

Clams are unlikely to be contaminated, and according to the Environmental Defense Fund's Seafood Selector, the farming of the most common clams in the U.S. (northern quahogs) does little ecological damage.

Recipes:
Linguine with White Clam Sauce

Photo: Joan Vicent Canto Roig / IStock

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If you're trying to get pregnant, make sure you're eating enough foods rich in Vitamin B12. New research published in this month's Pediatrics suggests women with low levels of Vitamin B12 just before or after conception are more likely to give birth to children with neural tube defects, according to the National Institutes of Health, Trinity College Dublin, and the Health Research Board of Ireland.

Most Vitamin B12 comes from meat or other animal-based food sources.

The research suggests that the same attention given to folic acid levels should be applied to Vitamin B12 levels.

In an effort to promote commonsense nutrition, The Daily Green publishes the Real Food Diet, lists of superfoods (along with the recipes to enjoy them) that contain high levels of various important nutrients, including Vitamin B12. By following simple guidelines -- eating a variety of nutritious foods, locally produced and in moderate portions -- good health is not far away.

This research, however, is a reminder that pregnant women, particularly, must take special care to fortify themselves with all the nutrients their developing babies need. In the case of Vitamin B12, that means a little meat. The good news for many vegetarians is that many fish and shellfish are among the top sources of Vitamin B12, so those vegetarians who allow themselves seafood can get plenty of this important nutrient without turning to meat or supplements.

Here's a look at the National Institutes of Health description of the new research:

To conduct the study, the researchers analyzed stored blood samples originally collected during early pregnancy from three groups of Irish women between 1983 and 1990. During that time, pregnant women in Ireland rarely took vitamin supplements. The study authors reasoned that the lack of routine vitamin supplementation would allow them to identify a sufficient number of women with low Vitamin B12 to conduct their analysis.

For their analysis, the researchers classified the women into three groups. The first group consisted of 95 women who were pregnant with a child having a neural tube defect at the time the blood was taken. The second group was composed of 107 women who had previously given birth to a child with a neural tube defect but whose current pregnancy was not affected. Like the first group, women in the third group (a total of 76) were pregnant with a child having a neural tube defect at the time the blood sample was obtained, but were enrolled in a different study than the women in group 1. The researchers measured the Vitamin B12 and folate levels of the women's blood samples, and compared them to those of control groups whose pregnancies were unaffected by a neural tube defect.

Because low folate levels are a known risk factor for neural tube defects, the researchers used statistical techniques to evaluate the role of Vitamin B12 independently of the role of folate. In all three groups, women with low B12 concentrations (estimated at less than 250 ng/L, before pregnancy) had 2.5-3 times the risk of having a child with a neural tube defect compared to those with higher levels. Women with levels in the deficient range (0-149 ng/L ) were at the highest risk: 5 times that of women with higher levels.

The study authors wrote that it is not known how B12 and folate might interact to influence the formation of the neural tube, the embryonic structure that gives rise to the spine and brain. They noted that the two vitamins are jointly involved with several key biochemical reactions, as well as with the synthesis of DNA. Lack of either Vitamin B12 or folate in any of these chemical processes theoretically could increase the risk of a neural tube defect.

The authors noted that their results needed to be confirmed by other studies among other populations of women. They suggested, however, that women should have Vitamin B12 levels above 300 ng/L before becoming pregnant. (Because B12 levels drop sharply during pregnancy, the researchers adjusted the levels measured during pregnancy to provide a target level for women to achieve before they become pregnant.)

Because Vitamin B12 comes from foods of animal origin, women who adhere to a strict vegan diet may be at risk for a B12 deficiency, said an NICHD author of the paper, James L. Mills, M.D., senior investigator in the Division of Epidemiology, Statistics, and Prevention Research. He added it is advisable for women with digestive disorders that interfere with the absorption of foods to consult a physician before getting pregnant, to make sure they are receiving adequate amounts of B12.

Dr. Mills explained that critical events in the formation of the brain and spinal column occur very early in pregnancy -- in the first 28 days after conception -- before many women even realize they are pregnant.

He added that the U.S. Public Health Service recommends that all women of childbearing age consume 400 micrograms of folic acid each day. This amount assures that a woman will have adequate stores of the vitamin, in the event of an unintended pregnancy.

Similarly, he said, it would be wise for all women of childbearing age to consume the recommended amount of Vitamin B12, whether they are planning a pregnancy or not.

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