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Nutrition Notes Topics

Folic Acid Preventing Fetal Abnormalities

The evidence is strong that folic acid supplementation at 400 mcg per day before and during pregnancy can reduce or eliminate neural tubes deficits that occur in the first 12 weeks of pregnancy. Neural tube deficits include anencephaly, meningomyelocele and encephalocele, three major abnormalities of the brain and spinal cord that are among the most common birth defects with severe mortality and morbidity. Neural tube defects occur with an incidence of 1-5 per 1000 births, showing marked geographic, ethnic and temporal variations.

Often pregnancy is diagnosed after 12 weeks and the opportunity to avoid the problem by supplementing mother’s diet with vitamins is too late. Folic acid is now a nutrient officially added to cereals as a public health measure with the hope of preventing endemic deficiency disease. In Canada, folic acid has been added to flour and the government has initiated a major public education campaign to recommend folic acid supplements to women who are likely to become pregnant. In the USA folic acid was added to cereal grains in 1998 at a dose of 140 micrograms/100 g.

Folic acid supplementation may have additional benefits. There is an increasing recognition that abnormalities in folic acid metabolism may be a cause for miscarriage and the development of a number of congenital abnormalities, including orofacial cleft anomalies and urinary tract anomalies. It has also been suggested that folic acid supplementation given before conception may be associated with an increase in birth weight and a slight decrease in the incidence of preterm labour and small-for-gestational-age babies.

Kadir and Economides reported on the success of the Canadian effort to increase folic acid intake: “2 groups report on the effect of the Canadian policy for folic acid fortification on the incidence of NTDs. Vidia Persad and coauthors showed a reduction of 54% in the total incidence (live births, stillbirths and terminated pregnancies) of open NTDs after 3 years of food fortification in Nova Scotia . Enza Gucciardi and coauthors reported a reduction of 50% in the birth incidence (live births and stillbirths) of NTDs in Ontario from 1986 to 1999, with most of the decrease occurring after 1995. They explain that the reduction after 1995 in the total incidence of NTDs is consistent with the expansion in the late 1990s in initiatives to promote folic acid use before conception among women of childbearing age and the 1998 policy to fortify flour and pasta. These data are also compatible with the success experienced in the United States with folic acid fortification, which was associated with a reduction of 19% in the birth incidence of NTDs.

Some Folic Acid Topics from Nutrition Notes

Rezan A. Kadir and Demetrios L. Economides Neural tube defects and periconceptional folic acid CMAJ • August 6, 2002; 167 (3) Birnbacher R; Messerschmidt AM; Pollak AP. Diagnosis and prevention of neural tube defects. Curr Opin Urol 2002 Nov;12(6):461-4 (ISSN: 0963-0643)

Folic acid deficiency diseases: Anemia, Neural Tube Defects, Arterial Disease, Dementia, Parkinson’s Disease, Colon and Breast Cancer. RDA 200 ug/day; 400 ug during pregnancy; 280 ug during lactation. Supplement Recommendation: 400 to 1000 ug/day