Methionine—an essential amino acid found in meat and dairy products, such as liver, eggs, cheese and milk—plays a role in normal embryo development in animals. Methionine is used in the same metabolic pathway as folic acid; when the body lacks folic acid, methionine intake becomes a limiting factor.

Examining mothers' dietary habits around conception and in early pregnancy, we found:

	Women who consumed more methionine had 30%-40% lower risk for neural tube defects; this was true regardless of folic acid intake.
	It's not certain if methionine or another correlated nutrient is associated with the risk reduction.

NUTRITIONAL FACTORS IMPORTANT IN GASTROSCHISIS

The younger the mother, the higher the risk for having a baby with gastroschisis, a serious abdominal wall defect. We theorized that teen mothers themselves may still be growing, thus competing with their pregnancy for nutrients. Indeed, nutritional deficiencies may play a role.

	Low vegetable and fruit consumption increased risk 3-fold.
	A 3-4 times greater risk was noted with low intake of carotenoids (found in fruits and vegetables) and glutathione (from animal protein or fruits/vegetables). Both nutrients are antioxidants and may protect the fetus from oxygen stress, a factor theorized to contribute to gastroschisis.
	High dietary levels of nitrosamines (found in preserved meats and beer) more than doubled risk.

NITRATES AND NEURAL TUBE DEFECTS

Nitrates—a commonly occurring group of substances found in foods, medications, drinking water, and cigarette smoke—have been implicated in cancer and other health outcomes. More than 85% of women's dietary nitrates came from fruits and vegetables. Nitrates in food did not increase risk for neural tube defects.

COFFEE AND DOWN SYNDROME

	Women with high coffee consumption (4 or more cups daily) were less likely to have recognized Down syndrome pregnancies. These pregnancies are prone to miscarriage; drinking coffee may increase this susceptibility, reducing the chance of having a recognized Down syndrome pregnancy. (Mothers who were high coffee consumers were about 50% more likely to have had a previous miscarriage.)
	Environmental factors—interacting with the developmental instability caused by an extra chromosome—may influence which babies with Down syndrome have associated abnormalities. 4.2% of mothers drank 4 or more cups of coffee daily; they had a 6 times higher chance of having a baby with Hirschsprung disease.