Accretion of carotenoids in chick plasma, tissues and retina after diets high in lutein, zeaxanthin or beta‐carotene

Lutein, zeaxanthin and β‐carotene are carotenoid pigments derived from plant foods. Lutein and zeaxanthin are especially concentrated in the retina. Low dietary intakes of lutein and zeaxanthin are associated with age‐related macular degeneration, atherosclerosis and cancer. β‐carotene, an important antioxidant, is converted to vitamin A in the intestine. Any excess is absorbed as β‐carotene. Chicks were fed diets high in lutein, zeaxanthin or β‐carotene to study their transport, distribution and interactions in plasma and tissues. One‐day‐old Leghorn chicks were randomly assigned to five groups (baseline, high lutein, high zeaxanthin, high β‐carotene, control); the latter four groups were fed up to 28 days. Plasma and tissues were analyzed on days 1, 14 and 28. Lutein and zeaxanthin were greatly increased in all tissues including the retina. In the high lutein group, zeaxanthin remained high in the retina, but decreased significantly in other tissues. In the high zeaxanthin group, lutein was stable in the retina but decreased in all other tissues. No β‐carotene was found in the retina of chicks fed a high β‐carotene diet even though levels were high in plasma and tissues. Plasma and tissue levels of lutein and zeaxanthin decreased after the high β‐carotene diet, but retinal levels remained unchanged. In summary, lutein and zeaxanthin were much higher in the retina than any other tissue. Only lutein and zeaxanthin were selectively retained in the retina, but were depleted in other tissues when the diet was deficient in one or the other. There was no lutein‐zeaxanthin interaction. Foundation Fighting Blindness.