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Previous evidence suggests a potential dual impact of aging and vitamin B6 (B6) deficiency on polyunsaturated fatty acid (PUFA) metabolism; gender may influence PUFA biosynthesis. Perturbation of PUFA compositions during B6 deficiency could be linked to age-related health outcomes. However, little is known about the interrelationships between vitamin B6, PUFA, and gender in the older population. Therefore, we investigated whether gender-specific associations of B6 intake and plasma pyridoxal 5’-phosphate (PLP) concentration, respectively, with plasma PUFA concentrations and ratios (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, and (EPA + DHA)/AA) existed in older adults. We further examined the relationships of adequate B6 status (PLP ≥ 20 nmol/L) with high (above median) plasma PUFA relative to deficient B6 status. This cross-sectional study analyzed 461 participants aged ≥60 years from NHANES 2003–2004. Nutrient intakes were assessed using two 24-h recalls and supplement questionnaires. PLP and PUFA concentrations were measured. Multivariate linear regression assessed the association of B6 intake and PLP with PUFA; multivariate logistic regression evaluated the relationship of adequate B6 status with high plasma PUFA, adjusting for demographic, socioeconomic, and dietary factors; physical activity; smoking; alcohol; medication; and BMI. There were interactions between gender and B6 intake on EPA (P-interaction = 0.008) and AA (P-interaction = 0.004) only, whereas no interaction existed between gender and PLP on PUFA. PLP was directly associated with EPA (β = 0.181, P = 0.002), DHA (β = 0.109, P = 0.005), EPA + DHA (β = 0.14, P = 0.002), EPA/AA (β = 0.186, P = 0.004), and (EPA + DHA)/AA (β = 0.13, P = 0.026). The odds of having high plasma EPA (adjusted (a) OR: 2.03, P = 0.049) and EPA/AA (aOR: 3.83, P < 0.0001) were greater in those with adequate B6 status compared to those with deficient B6 status. In conclusion, in US older adults, a higher PLP level was associated with a greater level of EPA, DHA, EPA + DHA, EPA/AA, and (EPA + DHA)/AA. Adequate B6 status was associated with high EPA and EPA/AA status. These findings suggest that sufficient vitamin B6 status may positively influence PUFA metabolism in older adults.

OBJECTIVES: Polyunsaturated fatty acids (PUFA) such as n-3 PUFA, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and n-6 PUFA, arachidonic acid (AA) may mediate inflammatory responses. Vitamin B6 deficiency has been shown to alter plasma PUFA levels. This perturbation of PUFA metabolism in vitamin B6 deficiency measured by pyridoxal-5’-phosphate (PLP) may contribute to inflammation. Thus, we aimed to examine the associations of 1) dietary EPA + DHA, and vitamin B6 with plasma ratio of AA/(EPA + DHA) by PLP level, 2) plasma AA/(EPA + DHA) and PLP with C-reactive protein (CRP), a marker for inflammation, and 3) dietary EPA + DHA, and vitamin B6 with CRP level, using NHANES. METHODS: NHANES datasets (2003–2004) with subjects ≥20 years were analyzed, accounting for survey design and sample weights (n = 4486). The significance level was P < 0.05. Covariates were age, gender, ethnicity, BMI, smoking, alcohol, total energy, dietary supplements, physical activity, and NSAIDs, depending on analyses. Multiple linear regression assessed the association of dietary EPA + DHA, and vitamin B6 with plasma ratio of AA/(EPA + DHA) by PLP level (Low: 3 mg/L); then, dietary EPA + DHA, and B6 with CRP level. RESULTS: In the low PLP level, dietary EPA + DHA was negatively associated with plasma ratio of AA/(EPA + DHA) (B = ─5.29, SE = 0.84, P = < .0001), but B6 intake was not, whereas, in the high PLP level, both dietary EPA + DHA (B = ─2.99, SE = 0.53, P = < .0001) and dietary vitamin B6 (B = ─0.21, SE = 0.04, P = 0.0001) were inversely associated with plasma AA/(EPA + DHA). Further, low PLP level was associated with greater odds of moderate to high CRP level compared to high PLP level (adjusted OR (aOR): 2.8, 95% CI: 1.93–4.04, P = < .0001), but plasma AA/(EPA + DHA) was not. In addition, both dietary EPA + DHA (aOR: 0.5, 95% CI: 0.23–0.98, P = 0.04) and vitamin B6 (aOR: 0.8, 95% CI: 0.68–0.95, P = 0.009) were inversely associated with moderate to high CRP level. CONCLUSIONS: Our findings show that low plasma PLP level and low vitamin B6 intake are associated with inflammation, and the relationship may be through their effect on PUFA metabolism, suggesting that increased intake of vitamin B6 and EPA and DHA may protect against inflammation. FUNDING SOURCES: N/A.

OBJECTIVES: Type 2 diabetes (T2D) is a complex and chronic metabolic disorder that involves complex interaction between environmental factors and genetic predisposition. TCF7L2 gene recently emerged as top candidate gene for T2D. Our study is aimed to assess six TCTL2 common polymorphisms: rs7903146, rs12255372, rs11196205, rs7901695, rs7895340 and rs4506565, in relation to T2D and related phenotypes in Cuban Americans who lived in Miami-Dade county, Florida. METHODS: We conducted a case-control study with 341 Cuban Americans (172 without T2D/169 with T2D). Unconditional logistic regression method was used to assess the association between six TCF7L2 SNPs and the risk of T2D in the additive genetic model, and further adjusted by potential confounding factors such as age, sex, BMI, physical activities and calorie intake. Student's t-tests on continuous values of T2D related quantitative traits were compared between risk allele carriers and non-carriers in control subjects. In addition, linkage disequilibrium and haplotype analysis were performed using Haploview 4.2. RESULTS: Four TCF7L2 SNPs (rs7901695, rs4506565, rs7903146 and rs11225537) were significantly associated with the risk of T2D in a Cuban American population after multivariable adjustment. Among non-diabetic control subjects, risk minor allele carriers of three TCF7L2 SNPs (rs7901695 (T > C), rs4506565 (A > T) and rs7903146 (C > T)) had significantly higher fasting glucose level and marginally higher level of glycated hemoglobin (A1C), compared to non-risk allele carriers. Consistently, results from haplotype analysis showed that two haplotypes TAC and CTT, formed by aforementioned three TCF7L2 SNPs (rs7901695, rs450565 and rs7903146), were significantly associated with the risk of T2D (P = 0.0094, and P = 0.0044, respectively), with the frequency of TAC significantly lower and CTT significantly higher in subjects with T2D, compared to subjects without T2D. CONCLUSIONS: The results of this study provide convincing evidence that variation in TCF7L2 genes confers strong susceptibility to T2D in the population studied. FUNDING SOURCES: Funding for this research was provided through an NIH/NIDDK sponsored grant. SUPPORTING TABLES, IMAGES AND/OR GRAPHS