Dietary folate intake in US adults: findings from the third National Health and Nutrition Examination Survey.

To estimate the dietary intake of folate in the US population, we used data from the first phase of the third National Health and Nutrition Examination Survey (NHANES III) conducted from 1988 through 1991. Using data from a single 24-hour dietary recall, the mean intake for the population aged 17 years and older was 283.4 microg/day (standard error [SE] 3.8). After correcting for a single 24-hour dietary recall, 70.0% (SE 1.1%) met the current recommended dietary allowance (RDA) for folate. Because data on intake of nutritional supplements were not available, it is likely that a higher proportion of the United States population met the RDA for folate. Folate intake was not uniform in the population: men had higher intakes than women, and African Americans had lower intakes than persons of other races. African-American men had lower absolute folate intakes than white men (P=0.001) or Mexican-American men (P=0.002). African-American women had the lowest folate intakes among women (P<0.001 for white women, P=0.006 for Mexican-American women, and P=0.003 for other women). When folate intakes were expressed as mg per 1,000 calories, the results were very similar. Because of methodologic differences in administering the 24-hour dietary recalls in NHANES II and NHANES III, it is unclear whether increases in dietary folate consumption have occurred since NHANES II, which was conducted during 1976-80, and the Continuing Survey of Food Intake by Individuals, which was conducted during 1985-86. The low dietary consumption of folate by African Americans, if confirmed, suggests the need for public health strategies to increase consumption of folate among this group.