Plasma carotenoids, tocopherols, and retinol : Associations with age and demographic characteristics in the age-stratified general population of the European MARK-AGE study

Dietary patterns as well as plasma concentrations of carotenoids, tocopherols, and retinol may differ between age groups and therefore may be associated with aging. For the MARK-AGE Project, a European multicentre study aimed to identify biomarkers of human aging, randomly recruited women and men from an age-stratified general population (35 - 75 years), as well as subjects from long-living families were recruited. Within this study we analyzed plasma micronutrients (six carotenoids, α- and γ-tocopherol, and retinol) among 2,118 participants. Plasma lycopene and α-/β-carotene were inversely correlated with age whereas β-cryptoxanthin, lutein, zeaxanthin, α-/γ-tocopherol and retinol were positively associated. The strong inverse association of lycopene and α-carotene with age and the positive association of α-tocopherol and β-cryptoxanthin with age were confirmed in multiple- and cholesterol-adjusted regression models. Age, country, season, and cholesterol were the main predictors for plasma concentrations of lycopene, α-tocopherol, β-cryptoxanthin, and α-carotene and were significantly affected by gender, smoking status, BMI, and dietary pattern. The decrease of lycopene with age remained after adjustment for significant co-factors and covariates, whereas the increase in α-tocopherol with age was less pronounced if all covariates including cholesterol and servings of vitamin supplements were assessed. The results of the MARK-AGE study suggest age as an independent predictor of plasma lycopene, α-tocopherol, and α-carotene. These micronutrients, together with other markers, may contribute to a set of biomarkers of human aging.