Tangerine tomatoes increase total and tetra-cis-lycopene isomer concentrations more than red tomatoes in healthy adult humans.

Lycopene, or the foods that contain it, may prevent prostate cancer. Studies suggest that some cis-lycopene isomers are more bioavailable than the trans-lycopene isomer. We hypothesized that tangerine tomatoes, which predominantly contain the tetra-cis isomer, should be a good source of bioavailable lycopene. We fed lunches containing 300 g tangerine or red tomato sauce per day to 21 healthy adults in a double-blind crossover design. We collected blood at baseline and after each treatment and washout period. We measured tetra-cis, other cis, and trans lycopene, as well as other carotenoids, by reversed-phase high-performance liquid chromatography. Both tomato sauces increased lycopene concentrations in blood, but the tangerine tomato sauce caused a greater increase of total and tetra-cis-lycopene. The cis isomer(s) may also have facilitated absorption of the trans-lycopene isomer. Indices of oxidative damage decreased as serum lycopene concentrations increased. Our results suggest that total lycopene concentrations can be increased by substituting tetra-cis-lycopene-rich tangerine tomatoes for common red tomatoes in the diet.