title: Effects of dietary protein, fat and beta-carotene levels on beta-carotene absorption in rats.
abstract: It is important that the factors influencing functional carotenoid absorption be made clear. The effect of rat diets containing different combinations of dietary protein, fat, and beta-carotene levels on beta-carotene absorption was evaluated. In the mid-level beta-carotene diet groups (1.8 mg beta-carotene/100 g diet), the retinol content in the liver and the ratio of the liver retinol content to the beta-carotene intake (namely, retinol accumulation rate) were both greater in the mid-level dietary protein groups (20 g protein/100 g diet) than in lower dietary protein groups (5 g protein/100 g diet), but were not affected by dietary fat level (10 g or 2 g fat/100 g diet). The liver beta-carotene content and its accumulation rate were lower in the mid-level dietary fat groups (10 g fat/100 g diet). beta-carotene 15,15'-dioxygenase (CDO) activity in the small intestine increased in the mid-level dietary protein groups, which resulted in an increase in the content of liver retinol converted from dietary beta-carotene. With respect to the mid-level dietary fat groups, the fecal beta-carotene excretion rate (%) increased. The low beta-carotene diet groups (0.006 mg beta-carotene/100 g diet) showed a higher serum retinol accumulation rate, CDO activity, and liver beta-carotene accumulation rate than the mid-level beta-carotene diet groups. These results suggest the marked effect of protein, fat, and beta-carotene level in diets on the absorption and metabolism of beta-carotene.
authors.affiliation: Faculty of Education, Wakayama University, Wakayama, Japan. hosotani@center.wakayama-u.ac.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hosotani
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kitagawa
mesh_terms: D000042:Absorption / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D007421:Intestine, Small / Q000201:enzymology; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D019207:beta Carotene / Q000008:administration & dosage* / Q000378:metabolism*; D050559:beta-Carotene 15,15'-Monooxygenase / Q000096:biosynthesis
chemical_list: D000975:Antioxidants; D004041:Dietary Fats; D004044:Dietary Proteins; D019207:beta Carotene; D050559:beta-Carotene 15,15'-Monooxygenase