A new study suggests that eating too much citrus fruits, especially grapefruit and orange, increases one's risk of developing melanoma by 36 percent.
Melanoma is a type of skin cancer affecting 65,647 people in the United States as of 2011. Earlier studies suggest that melanoma is genetic but can also be triggered by overexposure to sunlight and tanning beds that use ultraviolet light.
Researchers at Brown University looked at the data of 100,000 Americans. During the study period of 24 to 26 years, 1,840 of the participants were diagnosed with melanoma. The team then looked at the dietary patterns of these participants to determine a link between their food intake and skin cancer.
The analysis showed those who ate or drank one serving of citrus fruits or juice at least 1.6 times daily had an increased risk of developing skin cancer by 36 percent, compared to those whose consumption was only once or twice a week. The researchers considered other factors such as smoking and coffee consumption when they computed the risk, according to the Washington Post.
The researchers identified two fruits that were often consumed by the subjects, grapefruit and orange juice, that they believe were the main contributors of the increased risk because of their high levels of psoralens and furocoumarins which makes the skin more sensitive to sunlight. Thus, the researchers recommend people who regularly consume grapefruits and oranges to avoid too much exposure to sunlight.
An expert questioned the findings of the study because the melanoma cases were self-reported and there was no data of the form of the citrus fruits identified in the study.
"There is clearly a need for replication of the study findings in a different population before modifying current dietary advice to the public," Marianne Berwick from the department of internal medicine at the University of New Mexico told MedPage Today. She wrote a commentary about the study.
The study was published in the June 29 issue of the Journal of Clinical Oncology.