Pregnancy and nursing make female rats , and presumably women , especially susceptible to becoming choline deficient, the scientist said. The months before and immediately after childbirth appear to be special times when women need more in their diets.

Choline is a vitamin-like substance that is sometimes treated like B vitamins and folic acid in dietary recommendations. The body uses it in making the nerve messenger chemical known as acetylcholine and in building cell membrane , the biological "wrapper" that keeps cells from leaking.

A paper Zeisel ™s laboratory published in January in the Journal of Nutrition also showed that the nutrient folic acid is not just critical for brain development in embryos during the earliest stages of pregnancy, but it ™s a key to healthy brain growth and function late in pregnancy too.

Humans and other mammals lacking sufficient folic acid shortly before they are born can suffer lifelong brain impairment, the earlier UNC animal studies indicated. Such research can never be done directly in growing human fetuses for obvious reasons.

"In the past few years, folic acid has been the single greatest success story in nutrition and in preventing birth defects," Zeisel said. "Spina bifida, the early birth defect in which the spinal cord doesn ™t close, and anencephaly, a condition in which the brain doesn ™t form normally, can be eliminated between 50 and 85 percent of the time if women get sufficient folic acid before they become pregnant."

The National Institute on Aging supports the continuing studies at UNC, which maintains a federally designated and National Institutes of Health-supported Clinical Nutrition Research Unit. The U.S. Department of Agriculture recently released a choline food database Zeisel helped develop: www.nalda/fnic/foodcomp.