Associations Between Vitamin B6 Status and Plasma Polyunsaturated Fatty Acids Among US Older Adults: NHANES 2003–2004

Abstract

ObjectivesPrevious evidence suggests that vitamin B6 deficiency may have a deleterious impact on aging and the metabolism of polyunsaturated fatty acids (PUFA). However, the relationship of aging with vitamin B6 status and PUFA metabolism is poorly understood; population-based studies to assess the relationship between plasma pyridoxal 5′-phosphate (PLP; an active form of vitamin B6) and PUFA status for older adults are lacking. Thus, we examined the associations between plasma PLP concentration and plasma PUFA concentrations and ratios [eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, and (EPA + DHA)/AA] among US older adults. We further investigated the association of adequate (PLP ≥ 20 nmol/L) versus deficient (PLP < 20 nmol/L) vitamin B6 status in those participants with plasma PUFA concentration above the median. MethodsA cross-sectional study analyzed 467 participants aged ≥60 years from the National Health and Nutrition Examination Survey (NHANES) 2003–2004. Nutrient intake data were estimated from two 24-h recalls and from questionnaires on the use of supplements. Plasma PLP and PUFA concentrations were measured. We used multivariable linear regression for obtaining unstandardized (b) and standardized (β) coefficients; multivariable logistic regression for adjusted odds ratios. Covariates included demographic, socioeconomic, dietary variables, physical activity, smoking, alcohol consumption, prescription medication use, and BMI. ResultsPlasma PLP was directly associated with plasma EPA (β = 0.176, b = 0.101, P = 0.002), DHA (β = 0.109, b = 0.046, P = 0.004), EPA + DHA (β = 0.137, b = 0.060, P = 0.002), EPA/AA (β = 0.169, b = 0.089, P = 0.009). The odds of having plasma EPA/AA and (EPA + DHA)/AA concentration above the median were greater in those with adequate vitamin B6 compared with those who were deficient [adjusted OR (aOR): 1.32, 95% CI: 0.8–2.17, P = 0.0001; aOR: 2.08, 95% CI: 1.0–4.33, P = 0.049, respectively]. ConclusionsIn US older adults, plasma PLP was directly associated with plasma EPA, DHA, EPA + DHA, EPA/AA. Adequate vitamin B6 status was associated with having above the median EPA/AA and (EPA + DHA)/AA. These findings suggest that adequate B6 status may positively influence PUFA metabolism in the older US population. Funding SourcesNo funding sources.