HUMAN PLASMA CAROTENOID RESPONSE TO THE INGESTION OF CONTROLLED DIETSHIGH IN FRUITS AND VEGETABLES

Plasma carotenoid responses were determined in 36 healthy men and wome n before and after being fed controlled diets with a moderate amount o f fat (26% of total energy) and a high carotenoid content (approximate to 16 mg/d) for two 15-d periods. in addition, broccoli (205 g/d) was provided either during the first or the second 15-d residency period in a crossover design. Plasma was digested with lipase and cholesterol esterase, and carotenoids were extracted and measured by using HPLC. Three oxygenated carotenoids (lutein, zeaxanthin, and cryptoxanthin), three hydrocarbon carbon carotenoids (alpha-carotene, all-trans-beta-c arotene, and 13-cis-beta-carotene), and four geometric isomers of lyco pene (15-cis-, 13-cis-, 9-cis-, and all-trans-lycopene) were separated by using a C30 carotenoid column. A small unidentified peak coeluted with standard 9-cis-beta-carotene and was identified as zeta-carotene (lambda(max) = 400 nm). The concentrations of plasma lutein, cryptoxan thin, alpha-carotene, 13-cis-beta-carotene, all-trans-beta-carotene, a nd cis- and trans-lycopenes were all significantly increased (P < 0.05 ) on days 6-16 by the high-fruit and -vegetable diets. The provision o f additional broccoli for 5 d to the bas ic high-carotenoid diet resul ted in a further significant increase in the serum concentration of lu tein compared with the feeding of the basic high-carotenoid diet alone . Most of the measurable carotenoids of human plasma can be increased by moderate alterations in diet within a short time, although the magn itude of the plasma response may be related to the baseline caratenoid concentrations.