Excess vitamin E decreases canthaxanthin absorption in the rat

The recent attention given to the possible role of alpha-tocopherol (alpha- Toc) and carotenoids in the prevention and treatment of a variety of illnes ses resulted in segments of the population increasing their consumption of these nutrient/antioxidants. Once consumed, alpha-Toc and carotenoids are t hought to follow the same absorptive pathway and may influence each other's absorption, particularly when taken in large doses. The purpose of this st udy was to determine if alpha-Toc and the carotenoid, canthaxanthin (CTX), interact during absorption. Rats were intraduodenally infused with corn oil emulsions containing combinations of alpha-Toc (0 or 300 mu mol/L) and CTX (5, 10, 15, 20 mu mol/L) in a 2 x 4 factorial arrangement. Absorption was determined by measuring recovery of CTX and alpha-Toc in the mesenteric lym ph. The amount of CTX in the lymph increased significantly with the amount infused into the duodenum. The overall efficiency of CTX absorption from em ulsions without a-Toe averaged 12% with individual animals having a range o f 8 to 18%. Efficiency of absorption was not related to concentration of CT X infused. When alpha-Toc (300 mu mol/L) was added to the oil emulsion, the absorption of CTX was decreased by at least 50%. Recovery of alpha-Toc in the lymph averaged ca. 10% and was not affected by CTX. These results sugge st that concurrent consumption of a large dose of alpha-Toc may influence c arotenoid bioavailability.