Plasma vitamin profiles and their associations with metabolic health and mental wellbeing in midlife Asian women

Vitamins play an essential role in a variety of metabolic pathways involved in energy metabolism and neuronal function and hence, contribute to metabolic, mental and overall health and wellbeing. Women become more susceptible to vitamin deficiencies when transitioning into midlife due to changes in hormonal levels, nutrition, and lifestyle. These factors can potentially predispose them to changes in physical and mental health. The objective of this study is to examine associations between vitamins and health outcomes, including metabolic, mental and muscle health, among Asian women. Women were from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) a prospective longitudinal cohort study. The study measurements were performed in 662 women at postnatal 8-8.5 years study visits at a mean age of 39.9 years. Plasma vitamin concentrations were measured using liquid chromatography-tandem mass spectrometry (A, D, E, K, B) and microbiological assays (B12 and folate). Body mass index (BMI), blood pressure, fasting and post-oral glucose tolerance test 120-min glucose, insulin, HbA1c, triglycerides and HDL-cholesterol were measured. A composite metabolic syndrome (MetS) score was calculated. Self-administered Beck's Depression Inventory, State-Trait Anxiety Inventory and Perceived Stress Scale questionnaires were used to assess mental well-being. Hand grip strength (HGS) was measured using a dynamometer at year 11 study visits. Multivariable regression analyses were used to study the associations between plasma vitamins and metabolic, musculoskeletal and mental health outcomes. Thiamine monophosphate, pyridoxal-5'-phosphate, and cholecalciferol showed a positive association with favourable metabolic health outcomes such as reduced fasting insulin, increased HDL-cholesterol and reduced MetS scores. Plasma all-trans retinol, α-tocopherol, γ-tocopherol, and phylloquinone showed a positive association with increased MetS scores, however this was attenuated by taking into account triglyceride concentrations. Folate showed a positive association with decreased perceived stress. The significant inverse associations of the B-vitamers and cholecalciferol with MetS scores were only present in women with BMI ≥ 23 kg/m². Our analysis demonstrated significant associations of plasma vitamins with metabolic and mental health outcomes in the Asian women.