A new study by Harvard T.H. Chan School of Public Health researchers and colleagues found that consuming 1.6 ounces or more of citrus fruit every day was associated with an increased risk of melanoma. Although the overall risk was low — less than 2% of the more than 100,000 study participants who filled out dietary questionnaires over a 25-year-period developed melanoma — it was 36% higher among people who drank the most orange juice and ate the most grapefruit, as compared to those who consumed the lowest amounts.
The study was published online in the Journal of Clinical Oncology on June 29, 2015.
According to the researchers, the source of the association may be two compounds contained in citrus fruit, called psoralens and furocoumarins, that can affect the skin and its cells when exposed to ultraviolet light; however, more research is needed to confirm the link.
It’s also too soon to say that people should avoid citrus, co-author Walter Willett, Fredrick John Stare Professor of Epidemiology and Nutrition and chair of the Department of Nutrition, told NBC News.
He said that the study confirms the recommendation that people should eat a varied diet with not too much, or too little, of any one kind of food.