Some dietary fibers reduce the absorption of carotenoids in women

Dietary fiber may be partly responsible for the lower bioavailability of carotenoids from food than from purified supplements. Due to the lack of detailed information available, we investigated the effects of different kinds of dietary fiber on the absorption of carotenoids and α-tocopherol. Six healthy young women received an antioxidant mixture consisting of β- carotene, lycopene, lutein, canthaxanthin and α-tocopherol together with a standard meal. The meal did not contain additional dietary fiber or was enriched with pectin, guar, alginate, cellulose or wheat bran (0.15 g · kg body weight^-1). The increases in plasma carotenoid and α-tocopherol concentrations were followed over 24 h, and the areas-under-curves (AUC(24h)) were calculate d. The mean AUC(24h) of β-carotene was significantly (P < 0.05) reduced by the water-soluble fibers pectin, guar and alginate with a mean decrease of 33-43%. All tested fibers significantly reduced the AUG(24h)) of lycopene and utein by 40-74% (P < 0.05). The dietary fiber effect on the AUG(24h) of canthaxanthin was almost significant (P = 0.059) and there was no effect on the AUG(24h) of α-tocopherol. We conclude that the bioavailability of β-carotene, lycopene and lutein given within a mixed supplement is markedly reduced by different kinds of dietary fiber.