Carotenoid status in man: effects on biomarkers of eye, skin and cardiovascular health

Abstract

Observational epidemiological studies have consistently shown that a diet rich in carotenoid-containing fruit and vegetables is associated with a reduced risk of chronic diseases. Because intervention studies with hard endpoints are time-consuming and costly, the use of biomarkers could be a promising approach. We studied the relation between serum carotenoid concentrations in a normal physiological range and biomarkers of eye, skin and cardiovascular health.In a cross-sectional study among 376 subjects the associations between serum and adipose tissue lutein and macula pigment (MP) density in the eye were stronger in men than in women. MP density was inversely associated with lens density. Lens density was not related to serum and adipose tissue concentrations of lutein after adjustment for age. A modifying effect was observed on the association between serum carotenoids and minimal erythema dose, a marker of skin sensitivity to UV light. Several carotenoids were inversely associated with markers of inflammation markers and endothelial function.In a 1-year randomized double blind placebo-controlled trial among 341 subjects, the effects of 0, 7, 10 and 17 g/d consumption of sucrose polyesters (SPE) on serum carotenoids and functional biomakers were studied. Lipid standardized carotenoid concentrations decreased by 13-33% in the group consuming 17 g/d SPE in comparison with the control group. Decreases of serum carotenoids in the 10 g/d and 7 g/d SPE groups were less. No negative effects were observed on markers of oxidation, eye health, cardiovascular health, and immune status. In a 4-week randomized single blind placebo-controlled trial among 47 subjects, the effect of 500 g/d fruit and vegetables + 200 mL fruit juice was studied in comparison with 100 g/d fruit and vegetables consumption on serum carotenoids and biomarkers of cardiovascular health. Serum carotenoids increased by 22-128%. Homocysteine concentrations decreased by 11%. No effect was observed on serum lipids, blood pressure and fibrinolysis/coagulation variables.Overall, our studies used biomarkers that are indicative of biological processes currently thought to be important in disease etiology. But the predictive value has not been established. Therefore, our studies cannot be conclusive for disease risk. However, they seem to add proof to the hypothesis that serum carotenoid decreases or increases within normal physiological ranges in periods up to one year, have no or limited impact on biomarkers related to eye, skin and cardiovascular health