Canthaxanthin and Excess Vitamin A Alter α-Tocopherol, Carotenoid and Iron Status in Adult Rats

AŸ-Carotene and excess vitamin A have been shown to reduce plasma a-tocopherol when fed to young rats. The present study assessed the effects of AŸ- carotene, excess vitamin A and canthaxanthin (4,4'- diketo-AŸ-carotene) on carotenoid, a-tocopherol and iron status in adult retired breeder rats. Male8- to 10-mo-old rats (10/group) were fed varyinglevels of vitamin A as retinyl palmitate, AŸ-carotene and canthaxanthin ad libitum for 8 wk. The AIN-76Adiet was modified to contain 16% (wt/wt) fat and 50% carbohydrate (con trol) phis AŸ-carotene or canthaxanthin at 0, 0.048 (BC1 or CXI) and 0.2% (BC2 or CX2) of the diet. These compounds were fed with and without excess retinyl palmitate (RP, 220 mg/kg). Higherrelative liver weights were observed in CX-and RP-fedgroups. Plasma retinyl esters were detected in all RP-fedgroups. Plasma retinyl palmitate was 1.6- and 1.5-foldhigherin RP-BCand RP- CXgroups, respectively, than in the RP groups. Plasma and liver AŸ-carotene and canthaxanthin were 11-54% and 26-74% lower, respectively, with excess retinylpal mitate feeding. Feedingcanthaxanthin and retinylpalmi tate, but not AŸ-carotene, resulted in lower levels of plasma a-tocopherol. Liver non-heme iron levels were also lowerin CX-fedrats irrespective of retinylpalmitate feeding. These results extend to adult rats previous findings that excess retinyl palmitate alters vitamin E and carotenoid status prior to the manifestation of clinical signs of hypervitaminosisA. Additionally,can thaxanthin feeding lowers a-tocopherol and iron status in adult rats. J. Nutr. 121: 1649-1655, 1991.