Influence of dietary fats and vitamin E on plasma and hepatic vitamin A and beta-carotene levels in rats fed excess beta-carotene.
Effects of different dietary lipids and excess vitamin E on plasma and hepatic concentrations of beta-carotene were evaluated in rats fed diets containing a large excess (0.2%) of beta-carotene. Male weanling Wistar Kyoto rats were fed beta-carotene-supplemented diets containing various dietary lipids as follows: Group I, a saturated fat (coconut oil); Group II, a monounsaturated fat (olive oil); Group III, a polyunsaturated fat rich in omega-6 fatty acids (safflower oil); Group IV, same as Group III plus vitamin E; and Group V, a polyunsaturated fat rich in omega-3 fatty acids (menhaden oil). All diets contained 2% safflower oil to provide sufficient amounts of linoleic acid (an essential fatty acid). Rats were killed after six weeks of feeding the various diets, and the concentrations of beta-carotene and vitamin A were determined in plasma and liver. Plasma vitamin A levels were not altered by any of the dietary lipids or by an excess of vitamin E. The concentrations of beta-carotene in plasma were the lowest in rats fed the diet containing menhaden oil. The feeding of the diet containing an excess of vitamin E also resulted in a significant decrease in plasma beta-carotene concentration. Similarly, the hepatic beta-carotene concentration was also reduced to about one-half in rats fed the diet containing an excess of vitamin E. Liver beta-carotene concentration was higher in Groups II and III than in the other three dietary groups. Hepatic vitamin A concentrations were also affected by the type of dietary fat.(ABSTRACT TRUNCATED AT 250 WORDS)
Alam
B S
BS
Department of Biochemistry and Molecular Biology, LSU Medical Center, New Orleans 70119.
Brown
L R
LR
Alam
S Q
SQ
D000818:Animals; D002338:Carotenoids / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D004041:Dietary Fats / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D011921:Rats, Inbred WKY; D014801:Vitamin A / Q000097:blood / Q000378:metabolism*; D014810:Vitamin E / Q000494:pharmacology*; D019207:beta Carotene
D004041:Dietary Fats; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids