Interdisciplinary Research Center for Biosystems, Land Use and Nutrition (IFZ), Biometry and Population Genetics, Justus Liebig University, Giessen, Germany.
Nutrition Innovation Centre for food and Health (NICHE), Ulster University, Coleraine, United Kingdom.
J Nutr. 2020 Oct 12;150(10):2699-2706. doi: 10.1093/jn/nxaa225.
Riboflavin is required to generate the active form of vitamin B-6 (pyridoxal 5'-phosphate; PLP) in tissues, but the relevance of this metabolic interaction for nutritional status of vitamin B-6 is unclear because riboflavin biomarkers are rarely measured in human studies.
The purpose of this study was to identify the determinants of biomarkers of vitamin B-6 and riboflavin status and to examine the relationship between these nutrients in healthy adults.
Multiple linear regression was performed on observational data in 407 healthy adults aged 18-92 y who did not use B-vitamin supplements. Vitamin B-6 status was assessed by plasma PLP concentrations and erythrocyte glutathione reductase activation coefficient (EGRac) was used as a functional indicator of riboflavin status.
Dietary intakes of vitamin B-6 and riboflavin were below the average requirements in 10% and 29% of participants, respectively. Suboptimal status of vitamin B-6 (PLP ≤30.0 nmol/L) was more prevalent in adults aged ≥60 y than in younger participants (i.e., 14% compared with 5%), whereas a high proportion (i.e., overall 37%) of both age groups had deficient riboflavin status (EGRac ≥1.40). In multiple regression analysis, EGRac (P = 0.019) was a significant determinant of plasma PLP, along with dietary vitamin B-6 intake (P = 0.003), age (P < 0.001), BMI (kg/m2) (P = 0.031), and methylenetetrahydrofolate reductase gene (MTHFR) genotype (P < 0.001). Significant determinants of EGRac were dietary riboflavin intake (P < 0.001), age (P < 0.001) and MTHFR genotype (P = 0.020). Plasma PLP showed a stepwise decrease across riboflavin status categories from optimal (EGRac ≤1.26) to low (EGRac 1.27-1.39) to deficient status (P = 0.001), independent of dietary vitamin B-6 intake.
The findings are consistent with the known metabolic dependency of vitamin B-6 on riboflavin status and indicate that riboflavin may be the limiting nutrient, particularly in older people, for maintaining adequate vitamin B-6 status.
核黄素是在组织中生成维生素 B-6（吡哆醛 5'-磷酸；PLP）活性形式所必需的，但这种代谢相互作用与维生素 B-6 的营养状况的相关性尚不清楚，因为核黄素生物标志物在人体研究中很少被测量。
本研究旨在确定维生素 B-6 和核黄素状态的生物标志物的决定因素，并在健康成年人中研究这些营养素之间的关系。
对 407 名年龄在 18-92 岁之间、未服用 B 族维生素补充剂的健康成年人进行观察性数据的多元线性回归分析。通过血浆 PLP 浓度评估维生素 B-6 状况，红细胞谷胱甘肽还原酶激活系数（EGRac）作为核黄素状况的功能指标。
分别有 10%和 29%的参与者的维生素 B-6 和核黄素的膳食摄入量低于平均需求量。与年轻参与者相比，≥60 岁的成年人中维生素 B-6 状态不佳（PLP≤30.0nmol/L）更为普遍（即 14%比 5%），而两个年龄组的很大一部分（即总体 37%）都有核黄素状态不足（EGRac≥1.40）。在多元回归分析中，EGRac（P=0.019）与膳食维生素 B-6 摄入量（P=0.003）、年龄（P<0.001）、BMI（kg/m2）（P=0.031）和亚甲基四氢叶酸还原酶基因（MTHFR）基因型（P<0.001）一样，是血浆 PLP 的显著决定因素。EGRac 的显著决定因素是膳食核黄素摄入量（P<0.001）、年龄（P<0.001）和 MTHFR 基因型（P=0.020）。血浆 PLP 在核黄素状态类别中呈逐步下降，从最佳（EGRac≤1.26）到低（EGRac 1.27-1.39）到不足（P=0.001），独立于膳食维生素 B-6 摄入量。
这些发现与维生素 B-6 对核黄素状态的已知代谢依赖性一致，并表明核黄素可能是特别是在老年人中，维持足够的维生素 B-6 状态的限制营养素。
