According to the researchers, past studies have suggested that coffee consumption may protect against non-melanoma skin cancers, but it was unclear how such consumption affects melanoma skin cancers.

In this latest study, Erikka Loftfield, of the Division of Cancer Epidemiology and Genetics at the National Cancer Institute, and colleagues set out to determine how coffee consumption affects the risk of melanoma – the deadliest form of skin cancer .

The US is certainly a nation of coffee drinkers; more than half of us drink an average of 3.1 cups of it every day. And with the health benefits the beverage has been associated with in the past, it is no wonder.

The study, conducted by researchers from the National Cancer Institute at the National Institutes of Health (NIH) and Yale School of Public Health at Yale University in New Haven, CT, is published in the Journal of the National Cancer Institute.

Many of us turn to coffee for a morning boost, and now, a new study offers another excuse to drink the stimulating beverage; it could reduce the risk of melanoma skin cancer by a fifth.

To find out, the team assessed data from the NIH-AARP Diet and Health Study, involving 447,357 non-Hispanic white participants who were free of cancer at study baseline.

The participants completed a food frequency questionnaire at the beginning of the study – which detailed their coffee intake – and incidence of melanoma among subjects was monitored over an average of 10.5 years. During this time, 2,905 participants developed melanoma.

The researchers found that the more coffee participants consumed each day, the less likely they were to develop melanoma during the follow-up period. Drinking four cups of coffee a day, for example, was associated with a 20% lower risk of melanoma, the team reports.

These results remained even after accounting for participants’ age, sex, body mass index (BMI), alcohol intake, smoking history and ultraviolet (UV) radiation exposure – a primary risk factor for skin cancer.

The team notes the association was only found among participants who consumed caffeinated coffee, not decaffeinated. In addition, coffee only appeared to reduce the risk of malignant melanoma, not melanoma in situ – in which melanoma cells have not spread beyond the outer cells of the skin.

Commenting on their findings, the researchers say:

“Higher coffee intake was associated with a modest decrease in risk of melanoma in this large US cohort study. Additional investigations of coffee intake and its constituents, particularly caffeine, with melanoma are warranted.”

The team believes this “modest” reduction in melanoma risk from coffee consumption, however, may have big effects. “Because of its high disease burden, lifestyle modifications with even modest protective effects may have a meaningful impact on melanoma morbidity,” they add.

Talking to MNT, Loftfield said their findings do not indicate that individuals should increase their coffee intake to reduce the risk of skin cancer. “The most important thing that individuals can do to reduce their risk of melanoma is to reduce sun and UV radiation exposure,” she added.

While many studies have documented the positive health effects of coffee consumption, it is important to note the potential harms. The main ingredient in coffee is caffeine, a known stimulant. But consuming too much caffeine may lead to insomnia, nervousness, irritability, restlessness, fast heartbeat, muscle tremors and stomach upset.

In 2013, MNT reported on a study published in the journal Mayo Clinic Proceedings, in which researchers claim drinking four cups of coffee a day may raise the risk of premature death. Another study found that consuming just two cups of coffee a day could lead to urinary incontinence in men.

Our Knowledge Center article – “What are the health benefits of coffee?” – looks at some of the other ways in which the beverage can be good or bad for us.