New research presented at a conference in the US on Monday finds that drinking coffee is linked to a lower risk of a common form of skin cancer known as basal cell carcinoma (BCC). Results of a prospective study that followed over 25,000 cases of skin cancer suggest coffee may be an important dietary option to prevent BCC.

The research is the work of Dr Fengju Song and colleagues. Song is a postdoctoral fellow in the department of dermatology at Brigham and Women’s Hospital and Harvard Medical School.

For the study, the researchers used data from the Nurses’ Health Study, covering 72,921 participants followed from June 1984 to June 2008, and the Health Professionals Follow-Up Study, covering 39,976 participants from June 1986 to June 2008. These studies gathered detailed information about diet and health, including consumption of beverages such as coffee.

From those cohorts, the researchers identified 25,480 cases of skin cancer, comprising 22,786 BCC cases, 1,953 squamous cell carcinoma (SCC) cases, and 741 cases of melanoma.

Song and colleagues found a 20% reduction in risk for BCC among women who drank more than three cups of coffee per day, while for men who drank more than three cups per day the risk was 9% lower. These reductions were in comparison to counterparts who only drank less than 1 cup of coffee a month.

The relationship between amount of coffee consumed and BCC was inverse: that is more coffee was linked to lower risk, so that when participants were ranked according to how much coffee they drank, those in the top 20% of consumption (upper quintile) had the lowest risk, with 18% reduction for women and 13% reduction for men, compared to those in the lowest 20% of consumption (bottom quintile).

Song told the press:

“Given the nearly 1 million new cases of BCC diagnosed each year in the United States, daily dietary factors with even small protective effects may have great public health impact. Our study indicates that coffee consumption may be an important option to help prevent BCC.”

The researchers were quite surprised at the finding, and that it only applied to BCC and not the other types of skin cancer.

Animal studies have pointed to links between skin cancer risk and coffee consumption, but epidemiological studies in human populations have not arrived at the same conclusions, they said.

Song explained that tests on mice have shown that consuming caffeine or applying it to the skin reduces the number of UV-damaged keratinocytes (the most common cell type in the outer skin layer or epidermis) via programmed cell death or apoptosis, and that this also markedly reduces the subsequent development of SCC.

“However, in our cohort analysis, we did not find any inverse association between coffee consumption and the risk for SCC,” said Song, who suggests there is a need for further research that specifically addresses the link between coffee intake and BCC and also explores the underlying biological mechanism.

Written by Catharine Paddock PhD