Bioavailability of lutein from vegetables is 5 times higher than that of β-carotene

Abstract

Background: To gain more insight into the relation between vegetable consumption and the risk of chronic diseases, it is important to determine the bioavailability of carotenoids from vegetables and the effect of vegetable consumption on selected biomarkers of chronic diseases. Objective: To assess the bioavailability of β-carotene and lutein from vegetables and the effect of increased vegetable consumption on the ex vivo oxidizability of LDL. Design: Over 4 wk, 22 healthy adult subjects consumed a high-vegetable diet (490 g/d), 22 consumed a low-vegetable diet (130 g/d), and 10 consumed a low-vegetable diet supplemented with pure β-carotene (6 mg/d) and lutein (9 mg/d). Results: Plasma concentrations of vitamin C and carotenoids (ie, α- carotene, β-carotene, lutein, zeaxanthin, and β-cryptoxanthin) were significantly higher after the high-vegetable diet than after the low- vegetable diet. In addition to an increase in plasma β-carotene and lutein, the pure carotenoid-supplemented diet induced a significant decrease in plasma lycopene concentration of -0.11 μmol/L (95% CI: -0.21, -0.0061). The responses of plasma β-carotene and lutein to the high-vegetable diet were 14% and 67%, respectively, of those to the pure carotenoid-supplemented diet. Conversion of β-carotene to retinol may have attenuated its plasma response compared with that of lutein. There was no significant effect on the resistance of LDL to oxidation ex vivo. Conclusions: Increased vegetable consumption enhances plasma vitamin C and carotenoid concentrations, but not resistance of LDL to oxidation. The relative bioavailability of lutein from vegetables is higher than that of β-carotene.