Cutaneous squamous cell carcinoma is the second-most-common type of skin cancer among people with fair skin. Vitamin A, while known to be essential for the healthy growth and maturation of skin cells, has gotten mixed results in prior studies looking at its effectiveness in the reduction of skin cancer risk.
The research team in the current study looked at the diet and skin cancer results of participants in the Nurse’s Health Study and the Health Professionals Follow-Up Study, which, between the two, followed 173,229 U.S. men and women for nearly 30 years.
After adjusting for factors including the number of severe sunburns participants had received and family history of skin cancer, 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. Both groups ate more vitamin A on a daily basis than the U.S. Recommended Dietary Allowance.
Related: Organic Food Associated With Lower Cancer Risk Study Links Vitamin K2 to Cardiovascular HealthEunyoung Cho, associate professor of dermatology and epidemiology at Brown, noted that while plant-based sources of vitamin A have minimal side effects, too much vitamin A from supplements and animal sources can lead to nausea, liver toxicity, and increased risk of osteoporosis and hip fracture.
The next step, Cho said in the release, would be to conduct a clinical trial to find out if vitamin A supplements can prevent squamous cell carcinoma—but, she added, a dietary clinical trial is challenging on a technical level, and it’s difficult to ensure that participants actually stick to the diet. “If a clinical trial cannot be done,” she added, “then a large-scale prospective study like this is the best alternative for studying diet.”