Examination of circulating folate levels as a reflection of folate intakes among older adult supplement users and nonusers in the National Health and Nutrition Examination Survey 2003-2004.

High intakes of folic acid and/or elevated blood folate concentrations have been associated with negative health outcomes; thus, it is critical to identify those at greatest risk of such exposures. The goal of this research was to describe folate intakes (folic acid [μg], folate [μg], and total folate [dietary folate equivalent] from food) and identify people 45 years or older in the National Health and Nutrition Examination Survey 2003-2004 at risk of exposure to elevated serum folate concentrations (≥21.8 ng/mL [49.4 nmol/L]) when stratified by race or ethnicity and supplement use within sex. Black men consumed a lower mean food folate and exhibited lower red blood cell folate concentrations when compared to those of white or Mexican-American men (P<0.01 and P<0.01 for both). Black women consumed a lower food folate than Mexican-American women (P<0.01), less total folate (dietary folate equivalent) than white women (P<0.01), and had lower red blood cell folate concentrations than white women (P<0.01). Multivariate odds of elevated serum folate levels increased with age in men (P<0.001) and women (P=0.01). All white subjects and all supplement users (all P<0.001) were more likely to have elevated folate concentrations, while smoking reduced the odds of such exposures in women (P<0.001) and men (P=0.04). These findings highlight the need to understand the impact of chronic exposure to elevated folate intakes, especially among white subjects with increasing age and who use supplements.