Skin Lycopene Is Destroyed Preferentially over β-Carotene during Ultraviolet Irradiation in Humans

Abstract

This placebo-controlled study examined in healthy women the effects of ingestion of a single large dose of β-carotene (120 mg) on the concentrations of β-carotene and lycopene in plasma and skin, and the effects of UV light exposure on the concentrations of β-carotene and lycopene in the skin. Ingestion of β-carotene increased plasma β-carotene concentration by 127%, from 0.26 ± 0.06 (mean ± SEM) to 0.59 ± 0.07 µmol/L after 1 d, and the level remained elevated at 0.54 ± 0.11 µmol/L after 5 d. β-Carotene in skin, analyzed after 6 d, increased by 23%, from 1.41 ± 0.74 to 1.74 ± 0.72 nmol/g. β-Carotene ingestion had no effect on the lycopene concentrations of plasma (0.37 ± 0.11 µmol/L) or skin (1.60 ± 0.62 nmol/g). A single exposure of a small area of one volar forearm to a dose of solar-simulated light (three times the individually determined minimal erythema dose) resulted in 31 to 46% reductions in skin lycopene concentration compared with an adjacent non-exposed area. The same UV dose did not result in significant changes in skin β-carotene concentration. We conclude that a single 120-mg dose of β-carotene increases plasma and skin β-carotene concentrations and has no effect on plasma and skin lycopene concentrations. The amounts of lycopene in plasma and skin are comparable to or even greater than those of β-carotene. When skin is subjected to UV light stress, more skin lycopene is destroyed compared with β-carotene, suggesting a role of lycopene in mitigating oxidative damage in tissues.