Competition between ß-carotene and selected carotenoids for uptake by rat and human brush border membrane vesicles

Studies investigating carotenoid absorption in both humans and ferrets have reported competition between ß-carotene and several other carotenoids. The purpose of this study was to examine competition between ß-carotene and selected carotenoids for uptake into brush border membrane vesicles (BBMV). The use of BBMV to study carotenoid uptake has recently been validated in our laboratory (J. Nutrition (1996) 126:2904-2912) using both the rat and the Mongolian gerbil models, ß-carotene and selected carotenoids were incorporated into bile acid micelles and incubated with BBMV prepared from either rat or human small intestine. Data from uptake assays suggests that there is competition for uptake between ß-carotene and lycopene and also between ß-carotene and capsanthin. In both cases, ß-carotene was favored for uptake by both rat and human BBMV. Uptake data demonstrated a lack of competition between ß-carotene and lutein or between all-trans ß-carotene and 9-cis ß-carotene in either rat or human BBMV. The reported competition in humans between lutein and ß-carotene may occur subsequent to uptake by mucosal cells.