Usual folic acid intakes: a modelling exercise assessing changes in the amount of folic acid in foods and supplements, National Health and Nutrition Examination Survey, 2003-2008.

OBJECTIVE The USA currently fortifies enriched cereal grain products (ECGP) with folic acid at 140 μg/100 g. In addition, folic acid can be voluntarily added to ready-to-eat cereals (RTEC) up to 400 μg/serving and it is found in many dietary supplements, most often at a dose of 400 μg. We sought to model folic acid intake under various fortification and supplementation scenarios. DESIGN The National Health and Nutrition Examination Survey is a population-based cross-sectional survey representative of the non-institutionalized, civilian US population. Information on folic acid intake is collected in two 24 h dietary recalls and survey questions on dietary supplement use, which allows estimation of usual total folic acid intake. We modelled five different levels of folic acid fortification in ECGP, while varying the amounts in RTEC and dietary supplements. SETTING United States. SUBJECTS US adults (n 14 353) aged ≥19 years; non-pregnant women of childbearing age (n 4272). RESULTS The percentage of adults with usual daily folic acid intake above the tolerable upper intake level of 1000 μg was influenced more by the typical amount in supplements, while the median intake was influenced more by the ECGP fortification level. By manipulating the amount in at least two sources, it was possible to shift the distribution such that more women of childbearing age consumed the recommended intake of 400 μg of folic acid without increasing the percentage of adults with intake above the tolerable upper intake level. The results varied among population subgroups. CONCLUSIONS Our results suggest that combined strategies are required to meet population recommendations for folic acid intake.