Effects of lycopene and lutein supplementation on the expression of functionally associated surface molecules on blood monocytes from healthy male nonsmokers

It has been suggested that dietary carotenoids can enhance immune function. Supplementation with beta-carotene (15 mg daily) was previously shown to e nhance human monocyte function. To examine the effect of other dietary caro tenoids, two similar independent studies were done. Healthy adult male nons mokers were randomly assigned to receive lycopene (study 1), lutein (study 2), or placebo for 26 days, followed by the alternative treatment for anoth er 26 days. The expression of functionally related monocyte surface molecul es was quantified by laser flow cytometry before and after each treatment p eriod, There was a significant increase in plasma levels of each carotenoid following dietary supplementation, but the effects on monocyte surface mol ecule expression were not as striking as those observed after beta-carotene supplementation. These findings emphasize that it cannot be assumed that t he effect of one carotenoid will be the same as another, even at the same l evel of intake.