Vitamin E (α- and γ-tocopherol) - determinants and associated outcomes
Vitamin E is a lipid-soluble vitamin encompassing different vitamin E forms (α-, β-, γ-, δ-tocopherols, and tocotrienols) with important anti-oxidative functions. There is limited knowledge regarding the distribution of plasma vitamin E concentrations in the general Northern German population, the relation of vitamin E to dietary patterns, and its association with cardiometabolic traits. Therefore, in this thesis, the distribution of both α- and γ-tocopherol levels was assessed in a sample from the general population; and biochemical and dietary correlates of vitamin E were explored. We observed, that nearly 60% of the Northern German population had adequate plasma α-tocopherol levels (>30 µmol/L), and that lipid traits and the intake of vitamin E supplementation were statistically significantly associated with circulating vitamin E levels. However, neither a priori nor a posteriori derived dietary patterns displayed an association with circulating α- and γ-tocopherol levels. Furthermore, we explored associations of plasma vitamin E levels with the following cardiometabolic traits: The metabolic syndrome (MetS), visceral (VAT) and subcutaneous (SAT) adipose tissue, liver signal intensity (LSI), fatty liver disease (FLD), and gallstone disease. The α-tocopherol/cholesterol ratio was positively associated with MetS and VAT; and the γ-tocopherol/cholesterol ratio was positively associated with MetS, VAT, and SAT. Lower odds of having gallstone disease were observed in the top (compared to the bottom) tertile of the plasma α-tocopherol/cholesterol ratio. All analyses were conducted using data from the first follow-up examination (2010-2012) of the PopGen control cohort, a population-based sample from Northern Germany. Populations based, prospective studies are warranted to confirm our results and to further explore the potential impact of the reported findings on other nutritional and health outcomes.