EFFECT OF SIMULTANEOUS, SINGLE ORAL DOSES OF BETA-CAROTENE WITH LUTEIN OR LYCOPENE ON THE BETA-CAROTENE AND RETINYL ESTER RESPONSES IN THE TRIACYLGLYCEROL-RICH LIPOPROTEIN FRACTION OF MEN

The effects of lutein and lycopene on beta-carotene absorption and cle avage were investigated in 12 male subjects. Responses of carotenoids and retinyl palmitate in the triacylglycerol-rich lipoprotein (TRL) fr action after a separate 15-mg beta-carotene dose were compared with th ose after a dose of 15 mg beta-carotene combined with 15 mg lycopene o r lutein (given as natural concentrates or extracts). After combined d osing with lutein, the areas under the curve (AUCs) of beta-carotene a nd retinyl palmitate in the TRL fraction, adjusted for the triacylglyc erol response, were 66% (P = 0.019) and 74% (P <0.059), respectively, compared with 100% after dosing with beta-carotene alone. After combin ed dosing with lycopene these percentages were 90% and 101%, respectiv ely (NS). beta-Carotene conversion, estimated from the ratio between t he AUC for retinyl eaters and beta-carotene, assuming eccentric cleava ge, was 69%, 71%, and 72% for treatment with only beta-carotene, beta- carotene combined with lycopene, and beta-carotene combined with lutei n, respectively. In addition, a pilot study was performed to evaluate application of TRL response curves to measure absorption of carotenoid s from vegetable sources (15 mg carotenoid as carrots, spinach, and to mato paste). As compared with the carotenoid concentrates, responses w ere considerably lower or hardly measurable (beta-carotene and retinyl palmitate after carrots, lutein after spinach), except for lycopene a nd retinyl palmitate after a single dose of tomato paste. In conclusio n, this study showed that lutein, but not lycopene, negatively affecte d beta-carotene absorption when given simultaneously with beta-caroten e but apparently had no effect on beta-carotene cleavage.