Those daily cups of coffee may do more than just provide energy, they may be protective against the most common type of melanoma, says a new study from the National Cancer Institute at the National Institutes of Health (NIH).

Analyzing data from 447,357 non-Hispanic white subjects from the NIH-AARP Diet and Health Study, researchers found a 20 percent lower risk for malignant  melanoma for those who consumed four or more cups per day, compared to those who did not drink coffee.  

Participants, all cancer-free at baseline, answered food-frequency questionnaires, beginning in 1995/1996, with a median follow-up of 10 years. Researchers adjusted for ambient residential ultraviolet radiation exposure, body mass index, age, sex, physical activity, alcohol intake, and smoking history.

Melanoma is the most dangerous form of skin cancer, according to the Skin Cancer Foundation. The cancerous growths develop when unrepaired DNA damage to skin cells— most often caused by ultraviolet radiation— triggers mutations. Skin cells rapidly multiply and form malignant tumors originating in the pigment-producing melanocytes in the basal layer of the epidermis.  One person dies of melanoma every 57 minutes, according to the Skin Cancer Foundation and one in 50 people will be diagnosed in their lifetime.

Researchers found a statistically significant effect only for caffeinated coffee, but not decaffeinated. This may be due to chance, or a number of explanations, study author Erikka Loftfield, M.P.H., of the division of cancer epidemiology and genetics at the National Cancer Institute, told FoxNews.com in an email.

“Since the majority of coffee drinkers in our study primarily drank caffeinated coffee, we had better statistical power to detect an association for caffeinated than for decaffeinated coffee drinking,” she said, adding that caffeine or another component more abundant in caffeinated coffee could be related to the observed association.

Researchers also studied whether coffee had protection for melanoma in situ, stage 0 or noninvasive melanoma that may or may not progress to invasive melanoma. They did not find any protection.

Because previous studies had reported similar associations between coffee drinking and melanoma, in addition to their large study cohort and large number of melanoma cases, Lotfield said the team did not find the results to be surprising. Researchers did note that the limited study population means more study is needed.

While coffee drinkers should be reassured that their habit isn’t risky, their results do not indicate that individuals should alter their coffee intake.

“In the end, the most important thing that individuals can do to reduce their risk of melanoma is to reduce sun and UV radiation exposure,” Loftfield said.

The study was published in JNCI: Journal of the National Cancer Institute.