14 Jul 2017 --- Research involving mice that were fed a tomato-rich diet on a daily basis showed a reduction in the development of skin cancer tumors, by up to half in some cases.

The new study at Ohio State University shows how nutritional interventions can alter the risk for skin cancers. It has been published online in the journal Scientific Reports.

It found that male mice fed a diet of 10 percent tomato powder daily for 35 weeks, then exposed to ultraviolet light, experienced, on average, a 50 percent decrease in skin cancer tumors compared to mice that did not eat dehydrated tomato.

The theory behind the relationship between tomatoes and cancer is that dietary carotenoids, the pigmenting compounds that give tomatoes their color, may protect skin against UV light damage, says Jessica Cooperstone, co-author of the study and a research scientist in the Department of Food Science and Technology in the College of Food, Agricultural, and Environmental Sciences at Ohio State.

There were no significant differences in tumor numbers for the female mice in the study. Previous research has shown that male mice develop tumors earlier after UV exposure and that their tumors are more numerous, larger and more aggressive.

“This study showed us that we do need to consider sex when exploring different preventive strategies,” says the study's senior author, Tatiana Oberyszyn, a professor of pathology and member of Ohio State's Comprehensive Cancer Center.

“What works in men may not always work equally well in women and vice versa.”

There has been much work carried out previously directed towards tomato consumption and various health benefits.

Previous human clinical trials suggest that eating tomato paste over time can dampen sunburns, perhaps thanks to carotenoids from the plants that are deposited in the skin of humans after eating, and may be able to protect against UV light damage, Cooperstone says.

“Lycopene, the primary carotenoid in tomatoes, has been shown to be the most effective antioxidant of these pigments,” Professor Oberyszyn adds.

“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.”

Male VS Female Results
In the new study, the Ohio State researchers found that only male mice fed dehydrated red tomatoes had reductions in tumor growth. Those fed diets with tangerine tomatoes, which have been shown to be higher in bioavailable lycopene in previous research, had fewer tumors than the control group, but the difference was not statistically significant.

Cooperstone is currently researching tomato compounds other than lycopene that may impart health benefits.

Non-melanoma skin cancers are the most common of all cancers, with more new cases (5.4 million in 2012) each year than breast, prostate, lung and colon cancers combined, according to the American Cancer Society.

Despite a low mortality rate, these cancers are costly, disfiguring, and their rates are increasing, according to the US Department of Health and Human Services.

“Alternative methods for systemic protection, possibly through nutritional interventions to modulate risk for skin-related diseases, could provide a significant benefit,” Cooperstone says.

“Foods are not drugs, but they can possibly, over the lifetime of consumption, alter the development of certain diseases,” she says.

This was a three-year study that was supported by the National Institutes of Health through the National Cancer Institute.