Can Food Sources of Vitamin A Lower the Risk of Skin Cancer?
Posted: Monday, August 19, 2019
Vitamin A gets an “A” grade in its potential to reduce the incidence of cutaneous squamous cell carcinoma, according to research based on 26 years of data. The study findings, which were published in JAMA Dermatology, found a 17% reduced risk for people with the highest vitamin A dietary intake, particularly from fruits and vegetables but not supplement intake.
Whether vitamin A supplementation would work as well requires further research, wrote Jongwoo Kim, MD, MSc, of Warren Alpert Medical School of Brown University, Providence, Rhode Island, and colleagues. The cohort analysis included 48,400 American men from the Health Professionals Follow-up Study and 75,170 American women from the Nurses’ Health Study, all white (because of the low risk of squamous cell carcinoma in nonwhite populations); risk reduction was consistent between the sexes. Because those who consumed the most total vitamin A tended to be more physically active and less likely to smoke and consume alcohol, one study limitation is that those subjects “might also adopt better sun-protective behaviors…which we did not measure,” noted Dr. Kim and coauthors.
Still, with quintile 1 as the reference, the pooled multivariate hazard ratios for the increasing quintiles of total vitamin A intake were 0.97, 0.97, 0.93, and 0.83 for quintiles 2, 3, 4, and 5, respectively (P < .001 for trend). Higher intakes of retinol and some carotenoids were also associated with reduced risk, with the pooled hazard ratios for the highest compared with the lowest quintiles at 0.88 (P = .001 for trend) for total retinol, 0.86 (P = .001 for trend) for beta cryptoxanthin, 0.87 (P < .001 for trend) for lycopene, and 0.89 (P = .02 for trend) for lutein and zeaxanthin. (Vitamin A is the umbrella term for all the related compounds known as retinoids.)
In 26 years, a total of 3,978 cases of squamous cell carcinoma were documented in the 123,570 participants. Significantly, the association between vitamin A and reduced squamous cell carcinoma risk “appeared…more prominent among those with moles and those with burn or blistering sunburn reaction as children or adolescents,” observed the researchers.
Disclosure: The study authors’ disclosure information may be found at jamanetwork.com.