Eating a healthy diet rich in vitamin A may be a way to reduce skin cancer risk, research shows.
Findings from a team at Brown University were published in the Journal of the American Medical Association Dermatology.
The researchers showed that people whose diets included high levels of vitamin A had a 17% reduction in risk for getting the second most common type of skin cancer, as compared to those who ate modest amounts of foods and supplements rich in vitamin A.
Cutaneous squamous cell carcinoma was the second most common type of skin cancer among people with fair skin. Vitamin A was known to be essential for the healthy growth and maturation of skin cells, but prior studies on its effectiveness in reducing skin cancer risk had been mixed, said dermatology and epidemiology Associate Professor Eunyoung Cho, who led the research team.
The research team looked at the diet and skin cancer results of participants in two large, long-term observational studies: the Nurses’ Health Study, which followed 121,700 US women from 1984 to 2012, and the Health Professionals Follow-Up Study, which followed 51,529 US men from 1986 to 2012.
Between the two studies, about 123,000 participants were white (and thus had significant risk of developing skin cancer), had no prior history of cancer and completed dietary reports multiple times. Among these individuals included in the team’s subsequent analysis, 3978 cases of squamous cell carcinoma were reported and verified within the 24- or 26-year follow-up periods.
Both studies also asked the participants about hair colour, the number of severe sunburns they had received in their lifetime and any family history of skin cancer, and the researchers adjusted for these and other factors. The studies did not, however, ask participants about their avoidance of midday sun, known to be a major risk factor for skin cancer.
After grouping the study participants into five categories by vitamin A intake levels, the researchers found that people in the category with the highest average daily total vitamin A intake were 17% less likely to get skin cancer than those in the category with the lowest total vitamin A intake.
Most vitamin A came from the participants’ diets, particularly from fruits and vegetables, rather than from animal-based foods or vitamin supplements, the research found.
The researchers also found that eating high levels of other plant-based pigments similar to vitamin A — such as lycopene, commonly found in tomatoes and watermelon — was associated with decreased risk of skin cancer.
Associate Professor Cho said the study provided another reason to eat lots of fruits and vegetables as part of a healthy diet.
“Skin cancer, including squamous cell carcinoma, is hard to prevent, but this study suggests that eating a healthy diet rich in vitamin A may be a way to reduce your risk, in addition to wearing sunscreen and reducing sun exposure,” she said.