Lycopene and beta-carotene are bioavailable from lycopene 'red' carrots in humans

The purpose of this study was to determine if lycopene and beta-carotene are bioavailable from lycopene red carrots and if lycopene absorption is affected by carrot fiber.

Two crossover studies in humans attempted to compare the relative bioavailability of lycopene and beta-carotene from tomato paste to a 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 white carrots (0 mg lycopene/day), red carrots (5 mg/day), and tomato paste (20 mg/day). Study 2 (n=10) used red carrots (2.6 mg/day), tomato paste (5 mg/day), and tomato paste plus white carrots (5 mg/day). Each intervention lasted 11 days with a 10-day washout period between treatments. Serum lycopene and beta-carotene were measured by HPLC.

Statistical analysis indicated a significant effect of muffin type in study 1 (P<0.001), and a significant treatment by sequence interaction in study 2 (P=0.04). The response to increasing amounts of lycopene is linear at the levels fed in these studies (r=0.94). The data suggest that maintenance of serum lycopene concentrations at 0.3 micromol/l occurs at about 2 mg/day of lycopene from mixed dietary sources and a serum plateau occurs at >/=20 mg/day.

These results show that lycopene and beta-carotene are bioavailable from red carrots and lycopene absorption seems to be affected by carrot fiber. Making inferences from both studies, the lycopene in the red carrot is about 44% as bioavailable as that from tomato paste. Red carrots provide an alternative to tomato paste as a good dietary source of lycopene and also provide bioavailable beta-carotene.