by Justine Alford
Photo credit: Aggie 11, via Shutterstock.
Coffee worshippers of the world will be pleased to learn that a new study has found that regularly gulping this rich, aromatic beverage could help protect against a deadly type of cancer. Individuals in the study who consumed four or more cups of caffeinated coffee were around 20% less likely to develop malignant melanoma than those who don’t drink coffee. While the work backs up lab observations, people shouldn’t use these results to guide their coffee intake, and most importantly shouldn’t swap sunscreen for the drink.
Cutaneous melanoma, a form of skin cancer, is among the most common types of cancer and is the leading cause of skin cancer death in the US. Exposure to UV radiation is a well-established risk factor for the disease, although other factors also likely play a role. Various lab and animal based investigations have hinted that consuming coffee may help protect against UV-induced skin cancer, and human studies have previously identified associations between drinking coffee and lower rates of nonmelanoma skin cancers. Studies that looked into melanomas, however, produced a mixed bag of results, prompting scientists to initiate the current study.
For the investigation, scientists looked at almost half a million retirees who were cancer-free at the start of the study. The researchers tracked the participants for an average of 10.5 years and asked them to report their coffee consumption, alongside various other factors which could also influence their risk of developing cancer, such as alcohol consumption, smoking, BMI and exercise. To assess how much UV radiation participants were likely exposed to, they used NASA data on the amount of sunlight that their hometowns received.
During the course of the study, 2,904 cases of malignant melanoma were recorded, alongside 1,874 cases of melanoma in situ, which is the very earliest stage of melanoma. After taking all of the variables into consideration, they found that as compared with non-coffee drinkers, those who drank at least four cups of coffee a day had a 20% lower risk of developing malignant melanoma. Interestingly, they saw no association between coffee consumption and the risk of developing melanoma in situ, which could suggest the diseases have different etiologies.
They also found that the association only applied to caffeinated coffee, as a lower risk was not identified in those who drank decaf coffee. This could indicate that caffeine is responsible for the possible protective effect, which would support lab-based studies. However, it’s also possible that decaf coffee contains different amounts of other molecules which could be playing a role.
Although the study can’t prove that coffee truly does protect against skin cancer, the researchers have proposed a few potential mechanisms which could explain the associations observed. It could be that coffee prevents the development of cancer because it prevents DNA damage, or detoxifies carcinogens, which has been observed in cell culture. Furthermore, coffee roasting generates vitamins which have been demonstrated to protect against UV-induced skin cancer in mice.
While the study is certainly interesting, further research is warranted as the investigation was limited. It’s unclear at this stage which ingredient could be exerting these apparent effects. Furthermore, as pointed out by Live Science, the study relied on self-reporting, and participants may have differed in their use of sunscreen.