Race‐Ethnic Differences in B‐Vitamin Biomarkers and Intake Among US Adults in NHANES 2003–2006

Abstract

The water‐soluble B‐vitamins folate, B‐6, and B‐12 are cofactors in 1‐carbon and amino acid metabolism. Low biomarker levels are associated with an increased risk for certain birth defects and/or chronic diseases. Serum folate (S‐FOL) and red blood cell folate (RBC‐FOL), serum pyridoxal‐5′‐phosphate (PLP) and pyridoxic acid (4PA), serum vitamin B‐12 (B‐12), and nutrient‐specific total vitamin intake (from diet based on one 24‐h recall and from supplements) were assessed as part of NHANES 2003–2006. We investigated race‐ethnic differences in these outcome variables in US adults (蠅20 y) stratified by nutrient‐specific supplement use. Spearman correlation coefficients between B‐vitamin biomarkers and total intake were mostly weak (r <0.4); correlations were slightly higher in supplement users (SUP+; 0.23 蠄 r 蠄 0.46) compared to nonusers (SUP‐; 0.17 蠄 r 蠄 0.35). In SUP+, non‐Hispanic whites (NHW) had higher S‐FOL, RBC‐FOL, and 4PA, while non‐Hispanic blacks (NHB) had higher B‐12 geometric mean levels compared to NHW and Mexican Americans (MA). In SUP+, total median folate intake was higher in NHW compared to NHB, but there were no race‐ethnic differences for vitamins B‐6 and B‐12. In SUP‐, NHB had lower S‐FOL, RBC‐FOL, PLP, and 4PA geometric mean levels compared to MA and NHW; NHW had lower B‐12 concentrations compared to MA and NHB. In SUP‐, total median intakes for folate, B‐6, and B‐12 were lowest in NHB and similar in NHW and MA. These preliminary data show that race‐ethnic intake patterns in B‐vitamins do not always match biomarker patterns.