Lycopene isomers and carotenoid profiles in African American (AA) and Caucasian (C) men

African American men experience one of the highest rates of prostate cancer in the world which may be related to dietary patterns as well as interacting genetic and environmental factors. Our objective was to determine if significant differences in serum carotenoid and isomer profiles exist in AA (n=35) vs. C (n=35) men (ages 41-87) providing samples at a prostate cancer screening program in Louisiana. Lycopene exhibited the highest mean concentration for any carotenoid (total cis + trans, nmoles/L) with AA = 353 ± 35 vs. C = 413 ± 34 nmoles/L (mean ± SE, not significant by race). No significant differences between ethnic groups was observed for β-carotene, lutein/zeaxanthin, α/β-crytoxanthin, or α-carotene. There was no ethnic difference in the proportion of lycopene found in all trans vs. pooled cis (10-12 ispmers) which averages approximately 70% cis. The between person variation for each carotenoid and lycopene isomers is very large and probably represents differences in dietary consumption patterns of carotenoid-containing foods as well as poorly understood individual differences in absorption, tissue distribution, metabolism, and excretion. We detected no fundamental differences in serum lycopene isomer patterns between AA and C males suggesting that other factors probably account for the differences in prostate cancer risk observed in these ethnic groups. The hypothesis that tomato products and/or lycopene exhibits anti-prostate cancer properties in men of either race remains to be tested.