Dietary vitamin E and beta-carotene sources influence vitamin A and E storage in young rats fed marginal and adequate vitamin E.
The effects of two vitamin E levels (30 and 75 IU/kg diet) and the interrelation of two vitamin E sources [dl-alpha-tocopheryl acetate (dl-alpha-TA) and d-alpha-tocopheryl acid succinate (d-alpha-TAS)] and three vitamin A sources [retinyl palmitate (RP), all-trans synthetic beta-carotene (SBC), and natural beta-carotene (NBC)] were studied. Dietary vitamin A sources provided 4,000 IU/kg. Twelve groups of Fischer 344 rats (10/group) were fed designated diets for eight weeks. For RP, SBC, and NBC, the increase in each vitamin E source from a marginal to an adequate dietary level caused a significant increase in liver and heart alpha-tocopherol. Among rats fed diets with an adequate level of vitamin E, d-alpha-TAS was not as effective as dl-alpha-TA in increasing liver alpha-tocopherol levels. Plasma retinol was lower in rats fed d-alpha-TAS than in those fed dl-alpha-TA. Among rats fed diets with an adequate level of dl-alpha-TA, those fed SBC had significantly higher liver and heart alpha-tocopherol concentrations than did all other groups (p < 0.05). Liver retinol equivalents for rats fed NBC were approximately 66% lower than those in rats fed SBC or RP (p < 0.05). The roles of the two vitamin E sources in alpha-tocopherol metabolism are not equivalent. These data indicate that vitamin A source influences the magnitude of the tissue vitamin A and E changes in response to the two vitamin E sources.
Jenkins
M Y
MY
Office of Food Labeling, US Food and Drug Administration, Laurel, MD 20708, USA. myj@cfsan.fda.gov
Mitchell
G V
GV
Grundel
E
E
D000818:Animals; D002784:Cholesterol / Q000097:blood; D004032:Diet; D004435:Eating / Q000502:physiology; D008099:Liver / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009929:Organ Size / Q000502:physiology; D051381:Rats; D011916:Rats, Inbred F344; D014280:Triglycerides / Q000097:blood; D014801:Vitamin A / Q000097:blood / Q000378:metabolism*; D014810:Vitamin E / Q000378:metabolism / Q000494:pharmacology*; D019207:beta Carotene / Q000494:pharmacology*
D014280:Triglycerides; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002784:Cholesterol