BACKGROUND: US adults have access to multiple sources of folic acid. The contribution of these sources to usual intakes above the tolerable upper intake level (UL) (1000 microg/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 < or = 400 and >400 microg 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 < or =400 microg folic acid/d from supplements are unlikely to exceed the UL in intake for folic acid.
BACKGROUND: US adults have access to multiple sources of folic acid. The contribution of these sources to usual intakes above the tolerable upper intake level (UL) (1000 microg/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 < or = 400 and >400 microg 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 < or =400 microg folic acid/d from supplements are unlikely to exceed the UL in intake for folic acid.
Authors: James L Mills; Tonia C Carter; John M Scott; James F Troendle; Eileen R Gibney; Barry Shane; Peadar N Kirke; Per M Ueland; Lawrence C Brody; Anne M Molloy Journal: Am J Clin Nutr Date: 2011-06-08 Impact factor: 7.045
Authors: Christine M Pfeiffer; Maya R Sternberg; Zia Fazili; David A Lacher; Mindy Zhang; Clifford L Johnson; Heather C Hamner; Regan L Bailey; Jeanne I Rader; Sedigheh Yamini; R J Berry; Elizabeth A Yetley Journal: Br J Nutr Date: 2015-04-28 Impact factor: 3.718
Authors: Anna M Rozendaal; Anthonie J van Essen; Gerard J te Meerman; Marian K Bakker; Jan J van der Biezen; Sieneke M Goorhuis-Brouwer; Christl Vermeij-Keers; Hermien E K de Walle Journal: Eur J Epidemiol Date: 2013-10-04 Impact factor: 8.082