Dietary modulation of lens zeaxanthin in quail.

Abstract Although higher dietary intake of lutein/zeaxanthin has been associated with reduced risk for cataracts, the impact of dietary supplements on lens lutein (L) or zeaxanthin (Z) has not been examined. If higher lens carotenoids do reduce risk for cataract, it would be essential to know whether dietary carotenoids can elevate carotenoids in the adult vertebrate lens. In this study, a covey of Japanese quail were hatched and raised 6 months on carotenoid-deficient diet, then switched to deficient diet supplemented with low or high 3 R ,3 R ′-zeaxanthin (5 or 35 mg kg −1 food) or β-carotene (50 mg kg −1 food). Controls included a group of covey-mates that remained on the deficient diet and another raised from birth on the high Z (35 mg Z kg −1 ) diet. At 1 year of age, carotenoids and tocopherols in the lens and in the serum were analysed by HPLC, and compared by analysis of variance. Serum Z was significantly elevated in deficient birds fed the lower or higher Z supplement for 6 months ( P P As in humans, the predominant lens carotenoids were lutein (L) and zeaxanthin (Z), and the total carotenoid concentration was of lower magnitude than the concentration of α-tocopherol. Responses to Z supplementation were sex-related. Female quail had 5–10 times higher serum concentrations of both Z and L than males ( P P r =0.77; P −1 dose of Z for 6 months had a mean lens Z concentration (0.252±0.06 μg g −1 protein) close to that in females fed with the supplement from birth (0.282±0.15 μg g −1 protein). Birds fed with the higher dietary Z supplement for 6 or 12 months had significantly higher lens Z than birds fed lower or no dietary Z ( P These studies in quail provide the first experimental evidence that lens carotenoids in adult vertebrates can be manipulated by dietary Z supplements.