Absorption and metabolism of dietary carotenoids.

A number of carotenoids with diverse structures are present in foods and have beneficial effects on human health due to their common antioxidant activity and their respective biological activities. The major carotenoids found in human tissues, however, are limited to several including such as β-carotene, lycopene, and lutein. We have little knowledge of whether carotenoids are selectively absorbed in intestine and metabolized discriminately in the body. Moreover, the metabolic transformation of carotenoids in mammals other than vitamin A formation has not been fully elucidated. Here, the intestinal absorption and oxidative metabolism of dietary carotenoids are reviewed with a focus on dietary xanthophylls.