Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006.
October 18th, 2009 Posted by: admin
Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006.
Am J Clin Nutr. 2009 Oct 14;
Authors: Yang Q, Cogswell ME, Hamner HC, Carriquiry A, Bailey LB, Pfeiffer CM, Berry RJ
BACKGROUND: US adults have access to multiple sources of folic acid. The contribution of these sources to usual intakes above the tolerable upper level (UL) (1000 mug/d) and to folate and vitamin B-12 status is unknown. OBJECTIVE: The objective was to estimate usual folic acid intake above the UL and adjusted serum and red blood cell folate, vitamin B-12, methylmalonic acid, and homocysteine concentrations among US adults by 3 major folic acid intake sources-enriched cereal-grain products (ECGP), ready-to-eat cereals (RTE), and supplements (SUP)-categorized into 4 mutually exclusive consumption groups. DESIGN: We used data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 (n = 8258). RESULTS: Overall, 2.7% (95% CI: 1.9%, 3.5%) of adults consumed more than the UL of folic acid. The proportions of those who consumed folic acid from ECGP only, ECGP+RTE, ECGP+SUP, and ECGP+RTE+SUP were 42%, 18%, 25%, and 15%, respectively. Of 60% of adults who did not consume supplements containing folic acid (ECGP only and ECGP+RTE), 0% had intakes that exceeded the UL. Of 34% and 6% of adults who consumed supplements with an average of </=400 and >400 mug folic acid/d, <1% and 47.8% (95% CI: 39.6%, 56.0%), respectively, had intakes that exceeded the UL. Consumption of RTE and/or supplements with folic acid was associated with higher folate and vitamin B-12 and lower homocysteine concentrations, and consumption of supplements with vitamin B-12 was associated with lower methylmalonic acid concentrations (P < 0.001). CONCLUSION: At current fortification levels, US adults who do not consume supplements or who consume an average of </=400 mug folic acid/d from supplements are unlikely to exceed the UL in intake for folic acid.
PMID: 19828716 [PubMed - as supplied by publisher]
