Drug and environmental factors associated with adverse pregnancy outcomes. Part III: Folic acid: pharmacology, therapeutic recommendations, and economics.
OBJECTIVE
To review folic acid's mechanism of action, adverse effects, therapeutic recommendations, compliance, and cost.


METHODS
A MEDLINE search was conducted through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included folate, folic acid, neural tube defect, homocysteine, and methylenetetrahydrofolate reductase.


METHODS
Animal and human studies examining the effects of folate were reviewed.


METHODS
Data collected included mechanism of action, safety issues, dosing recommendations, compliance with recommendations, and economics.


RESULTS
Folic acid decreases neural tube defect risk through an effect on methionine-homocysteine metabolism. In addition, increased folate intake may reduce cardiovascular morbidity and mortality. Since toxicity is minimal, everyone can potentially benefit from increased folate consumption. To help achieve this, the Food and Drug Administration has mandated that cereal grain be fortified with 140 micrograms of folic acid per 100 g of grain, which will add approximately 0.1 mg of folate to the average diet. Studies recommend supplementing with 0.2 mg to promote optimal homocysteine concentrations and for preventing neural tube defects.


CONCLUSIONS
Despite fortification, most women will still receive less folate than the 0.4 mg/d recommended by the Public Health Service. All population groups would benefit from increased folate intake. Current studies indicate 200 micrograms/d may be the minimum effective amount of fortification needed for normalizing homocysteine concentrations and preventing a significant number of neural tube defects; thus, a higher level of food fortification may be warranted.
Lewis
D P
DP
College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA.
Van Dyke
D C
DC
Stumbo
P J
PJ
Berg
M J
MJ
D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000009:adverse effects*; D005260:Female; D005492:Folic Acid / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D005527:Food, Fortified / Q000191:economics; D006397:Hematinics / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome
D004785:Environmental Pollutants; D006397:Hematinics; D005492:Folic Acid