The Protective Role of Tomatoes in Non-Melanoma Skin Cancer

Daily consumption of tomatoes could cut the risk of skin cancer in half, new findings suggest.

Scientists have theorized that dietary carotenoid, the pigmenting compounds that give tomatoes their color, may protect skin against UV light damage; however, other phytochemicals may play role.

In a study published in Scientific Reports, investigators sought to determine whether dietary consumption of tomatoes—–either as a tangerine or red variety––compared with a tomato-free diet, could reduce the ultraviolet B (UVB)-induced tumor promotion and progression.

The investigators used SKH-1 hairless and immunocompetent mice for the study, and fed them AIN-93G or AIN-93G plus 10% tangerine or red tomato powder for 35 weeks. The control mice were fed the same diets, but were not exposed to UV.

From weeks 11 to 20, the mice were exposed to 2240 J/m² UV-B light 3 times per week. The tumors were tracked weekly.

The results of the study showed that the number of tumors was significantly lower in male mice fed a diet of 10% tomato powder daily for 35 weeks compared with the controls. On average, they had a 50% decrease in skin cancer tumors compared with the control mice.

Furthermore, carotenoid levels in plasma and skin were quantitated and found that total lycopene was higher in the skin of tangerine fed animals despite a lower dose.

No significant differences were observed in tumor numbers among the female mice. Prior studies have shown that male mice are more likely to develop tumors earlier and have more of them that are often large and aggressive.

“This study showed us that we do not need to consider sex when exploring different preventive strategies,” said senior author Tatiana Oberyszyn. “What works in men may not always work equally well in women and vice versa.”

Prior human clinical trials have suggested that tomato paste consumption can dampen sunburns. Co-author Jessica Cooperstone noted that the finds may point towards the carotenoids.

“Lycopene, the primary carotenoid in tomatoes, has been shown to be the most effective antioxidant of these pigments,” Cooperstone said. “However, when comparing lycopene administered from a whole food (tomato) or a synthesized supplement, tomatoes appear more effective in preventing redness after UV exposure, suggesting other compounds in tomatoes may also be at play.”

Non-melanoma skin cancers are the most common of all cancers, according to the American Cancer Society. Although mortality rates are low for these cancers, they are costly, disfiguring, and the rates are increasing, the Department of Health and Human Services reports.

“Alternative methods of systemic protection, possibly through nutritional interventions to modulate risk for skin-related diseases, could provide a significant benefit,” Cooperstone said. “Foods are not drugs, but they can possibly, over the lifetime of consumption, alter the development of certain diseases.”

The investigators are currently researching other tomato compounds in hopes they may provide health benefits.