Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/21/2003
Publication Date: 7/29/2004
Citation: Horvitz, M.A., Simon, P.W., Tanumihardjo, S.A. 2004. Relative bioavailability of lycopene from lycopene "red" carrots compared to tomato. American Journal of Clinical Nutrition. Interpretive Summary: While typical carrots are orange, we have developed red carrots which have the same pigments, called lycopenes, as red tomato. Lycopenes help prevent some forms of cancer. In this study we fed red carrots or tomatoes to humans and then evaluated how much pigment was absorbed into their blood. Red carrots and tomatoes both delivered lycopenes to the bloodstream, although red carrot pigment delivery was less efficient. This is of interest to vegetable growers, nutritionists, and consumers since it demonstrates that red carrots can be a useful alternative to tomatoes in producing lycopenes in the diet.
Technical Abstract: Epidemiological evidence has found an inverse association with lycopene consumption and the incidence of cancers. The primary sources of dietary lycopene are tomatoes and tomato products. Two crossover studies were conducted in humans to compare the relative bioavailability of lycopene from tomato paste to genetically selected lycopene red carrot during chronic feeding. Each study contained three treatment groups. The vehicle of administration was muffins. Study 1 (n=9) used red carrots (5 mg lycopene/d), white carrots, (0 mg/d), and tomato paste (20 mg/d). Study 2 (n=10) used red carrots (2.6 mg/d), tomato paste (5 mg/d), and tomato paste plus white carrots (5 mg/d). Each intervention lasted 11 days with a 10-day washout period between treatments. Serum lycopene and ß-carotene were measured by HPLC. Statistical analysis indicated a significant effect of treatment in the first study (P < 0.001), and a significant treatment by sequence interaction in the second study (P = 0.04). The response to increasing amounts of lycopene is linear at the levels fed in these studies (r = 0.937). Maintenance of serum lycopene concentrations occurs at about 2 mg/d of lycopene from mixed dietary sources and a serum plateau occurs at > or = 20 mg/d. These results suggest that lycopene is more bioavailable from processed tomato products than from red carrots. However, the lycopene from the red carrot is bioavailable, and provides an alternative to tomatoes as a dietary source of lycopene.