Abstract
Defective metabolism of the essential amino acid methionine, resulting in overt hyperhomocysteinemia or situational hyperhomocysteinemia (after a methionine load), has been established as an independent risk factor for atherosclerotic heart disease. Nutrients involved in the pathways of homocysteine degradation, including folic acid, vitamins B6 and B12 all have a connection to negative pregnancy outcomes, which may be related to their impact on homocysteine. Dietary intake and metabolism of folic acid, the nutrient most closely identified with neural tube defects, has been studied in depth for the past fifteen years. The information from these studies has illuminated the mechanisms of these congenital defects, and has lead to the discovery of connections with other nutrients related to homocysteine metabolism which may also be involved in negative pregnancy outcomes, including spontaneous abortion, placental abruption (infarct), pre-term delivery, and low infant birth weight. (Alt Med Rev 1996;1(4):220-235)