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IN 1996, the Food and Drug Administration (FDA) issued a regulation, to be effective by January 1998, requiring that all enriched flour, rice, pasta, cornmeal, and other grain products contain 140 ug of folic acid per 100 g in addition to the thiamine, riboflavin, niacin, and iron already present in such products. The goal of this folic acid fortification was to increase the intake of folate by women of childbearing age in response to the recommendation of the Public Health Service that "all women of childbearing age in the United States who are capable of becoming pregnant should consume 0.4 mg of folic acid per day for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other NTDs (neural tube defects)." This recommendation followed the release of the results of a randomized, controlled clinical trial that found that vitamin supplements containing folic acid prevented many neural-tube defects. This outcome was consistent with the results of other randomized trials nonrandomized trials and observational studies of periconceptional folate intake. It was estimated that folic acid fortification at the level of 140 ug per 100 g would provide an additional 80 to 100 ug of folic acid per day to the diet of women of childbearing age and 70 to 120 ug to the diet of middle-aged and older adults. Unfortunately, not all of us have the time to follow a healthy diet, making supplementation imperative.
Background: In 1996, the Food and Drug Administration issued a regulation requiring all enriched grain products to be fortified with folic acid to reduce the risk of neural-tube defects in newborns. Fortification (140 [ug per 100 g) began in 1996, and the process was essentially complete by mid-1997.
Methods: To assess the effect of folic acid fortification on folate status, we measured plasma folate and total homocysteine concentrations (a sensitive marker of folate status) using blood samples from the fifth examination (January 1991 to December 1994) of the Framingham Offspring Study cohort for baseline values and the sixth examination (January 1995 to August 1998) for follow-up values. We divided the cohort into two groups on the basis of the date of their follow-up examination: the study group consisted of 350 subjects who were seen after fortification (September 1997 to March 1998), and the control group consisted of 756 subjects who were seen before fortification (January 1995 to September 1996).
Results: Among the subjects in the study group who did not use vitamin supplements, the mean folate concentrations increased from 4.6 to 10.0 ng per milliliter (11 to 23 nmol per liter) (P<0.001) from the baseline visit to the follow-up visit, and the prevalence of low folate concentrations (<3 ng per milliliter [7 nmol per liter]) decreased from 22.0 to 1.7 percent (P< 0.001). The mean total homocysteine concentration decreased from 10.1 to 9.4 umol per liter during this period (P<0.001), and the prevalence of high homocysteine concentrations (>13 umol per liter) decreased from 18.7 to 9.8 percent (P<0.001). In the control group, there were no statistically significant changes in concentrations of folate or homocysteine.
Conclusions: The
fortification of enriched grain products with folic acid was associated with a substantial
improvement in folate status in a population of middle-aged and older adults.
N Engl J Med 1999;340:1449-54
1999, Massachusetts Medical Society.