Caffeine addicts rejoice at a new study conducted by researchers at the National Cancer Institute and the Yale School of Public Heath, which finds that drinking caffeinated coffee can reduce the risk of developing melanoma by as much as 20 percent.

Melanoma is the fifth most common cancer and the deadliest cause of skin cancer in the United States, with a death rate of about 9,500 people each year. The most common controllable risk factor for preventing melanoma remains limiting exposure to harmful UV rays, but now both lab and human studies show that drinking coffee can play a protective role.

Researchers studied a pool of over 447,000 participants over an average period of 10.5 years. The subjects were all non-Latino white participants between 50-71 years old, and cancer-free at the start of the study. Over the next decade, 2,905 of the participants developed malignant melanoma, and over 1,900 developed melanoma in situ, which is an early, less invasive form of the disease. Despite various differences in participants’ physical attributes and lifestyle choices –  including age, sex, alcohol intake, and even UV radiation exposure – drinking four or more cups of coffee a day consistently reduced the risk of malignant melanoma by about 20 percent.

This result supports previous findings in lab studies that natural compounds in coffee can protect skin cells from DNA damage, inflammation, and oxidative stress. However, only those who drank caffeinated coffee benefited from the positive effects. Researchers also say that caffeine itself, whether ingested or topically applied, has been shown to absorb UV radiation, acting as kind of a low-grade sunblock.

While the results of the study may lead to a more comprehensive defense in the fight against skin cancer, critics still question the overall benefits of drinking large amounts of coffee. The researchers conclude that “additional investigations of coffee intake […] in the prevention of melanoma are warranted,” but they insist that the most reliable method of reducing the risk of skin cancer remains simply staying out of the sun.