Lutein and β-carotene from lutein-containing yellow carrots are bioavailable in humans

Abstract

Lutein is a hydroxy-carotenoid constituting the macular pigment of the human retina. Increasing lutein intake from foods could increase the density of this pigment and decrease the risk of developing macular degeneration. Yellow carrots are a novel food source that could increase lutein consumption. We evaluated and compared lutein uptake and clearance in humans from genetically selected lutein-containing yellow carrots fed chronically and from a lutein supplement. Four women and 5 men aged 23-28 y participated in this randomized, blinded, 3 x 3 crossover intervention. Treatments consisted of yellow carrots (YC treatment, 1.7 mg lutein/d), white carrots as a negative control (WC treatment, 0 mg lutein/d), and a lutein supplement in oil as a positive control (LS treatment, 1.7 mg lutein/d). Each treatment lasted 7 d and was followed by a 7-d washout period. Mean (+/- SD) peak changes in serum lutein concentration from baseline were 0.31 +/- 0.08, 0.19 +/- 0.08, and -0.04 +/- 0.04 micromol/L for the LS, YC, and WC treatments, respectively. The areas under the curve for 0-14 d (AUC(0-14d)) differed significantly (P < 0.0001) between treatments. Lutein from the YC treatment was 65% as bioavailable as that from the LS treatment. The AUC(0-14d) for beta-carotene (-0.01 +/- 0.28 micromol.d/L) also showed that the YC treatment maintained peak serum beta-carotene concentrations at 0.35 +/- 0.30 micromol/L, whereas the LS treatment did not (AUC(0-14d) = -0.71 +/- 0.59 micromol.d/L). Lutein from this novel food source significantly increases serum lutein concentrations and does not result in the decrease in beta-carotene concentrations that accompanies administration of lutein supplements.