Intestinal absorption of dietary carotenoids

Abstract

The assessment of carotenoid bioavailability has long been hampered by the limited knowledge of their absorption mechanisms. However, recent reports have elucidated important aspects of carotenoid digestion and absorption. Disruption of food matrix and increasing amounts of fat seem to enhance the absorption of carotenes to a larger extent than that of xanthophylls. Comparing different carotenoid species, xanthophylls seem to be more easily released from the food matrix and more efficiently micellized than the carotenes. On the other hand, carotenes are more efficiently taken up by the enterocytes. However, carotenoid emulsification and micellization steps are largely affected by the food matrix and dietary components, being the main determinant of carotenoid bioavailability from foodstuffs. Although the intestinal uptake of carotenoids has been thought to occur by simple diffusion, recent studies reported the existence of receptor-mediated transport of carotenoids in enterocytes. Comparisons between the intestinal absorption of a wide array of carotenoids would be useful to elucidate the absorption mechanism of each carotenoid species, in view of the recent indications that intestinal carotenoid uptake may involve the scavenger receptor class B type I and possibly other epithelial transporters. The unraveling of the whole mechanism underlying the absorption of carotenoids will be the challenge for future studies.

β-Carotene conversion products and their effects on adipose tissue

“…At the intestinal level, b-carotene absorption is depending on three steps: (1) absorption at the enterocyte brush border membrane level, partly via the cholesterol transporters SR-BI and CD36 [11,71] but also by passive diffusion [83]; (2) enzymatic conversion of a fraction of absorbed b-carotene in a centric or eccentric fashion by the b-carotene 15,15 0 -monooxygenase BCMO1 (releasing retinal) or by the b-carotene 9 0 ,10 0 -dioxygenase, BCDO2 (releasing b-apo-10 0 -carotenal and b-ionone), respectively (Fig. 2, for review see [73].…”

Comparison of tetrahydrofuran, fetal calf serum, and Tween 40 for the delivery of astaxanthin and canthaxanthin to HepG2 cells

“…Humans and animals are not capable of carotenoid biosynthesis, but ingest them as part of their diets. Of the approximately 60 carotenoids present in the human diet, only about 20 have been detected in human blood and tissues (Yonekura and Nagao 2007).…”

Bioavailability of Palm Oil Carotenoids Consumed from Different Foods

“…Their non-digestible character in human digestive prevents production of micelles by inhibiting digestive lipases activity and/or by binding to bile acids or to phospholipids. Fibers also increase intestinal content, viscosity and volume thereby slowing processes of diffusion of micelles on the absorbent surface of enterocytes (Yonekura & Nagao, 2007;Eroglu & Harrison, 2013). Besides, Riedl et al (1999) confirmed that dietary fibers decrease carotenoids absorption in human.…”

“…These quantities are greater than the minimal quantity of lipids required in a meal (3-5 g) for a good assimilation of carotenoids (Yonekura & Nagao, 2007;Goltz et al, 2012;Hammond & Renzi, 2013).…”