Usually, the intestinal absorption of lutein and zeaxanthin is determined by analyzing changes in concentrations in blood plasma. A fast, non-invasive sampling will be evaluated to check the efficacy of an increased uptake of lutein. Thus, the project will test the usability of buccal mucosa cells to detect metabolic changes after an uptake of carotenoids. Besides, the determination of carotenoid contents in skin will be checked on its use as biomarker of carotenoids in plasma and macula.