Absorption of beta-carotene and other carotenoids in humans and animal models.

OBJECTIVE

To review available information on absorption and further metabolism of different carotenoids in man and to discuss animal models and approaches in the study of carotenoid absorption and metabolism in man.

CONCLUSIONS

Humans appear to absorb various carotenoids in a relatively non-specific fashion, but absorption kinetics and plasma transport seem to differ among carotenoids, possibly because of differences in polarity. Absorbed beta-carotene for the most part is converted, mainly into retinyl esters, but several details with respect to the cleavage reaction remain to be elucidated. Although interactions among carotenoids do exist, their importance and the mechanisms involved are still unclear. No animal model reflects the human situation for beta-carotene metabolism entirely. Thus, for every research question, the optimal model needs to be selected. Methods available for studying beta-carotene metabolism in man are limited. The most promising methods are the single dose-response in chylomicrons, and plasma responses after dosing with stable isotopes.