Does citrus have a sour side? A new study, published in the Journal of Clinical Oncology, has prompted questions about the association between citrus consumption and increased risk of melanoma (a type of skin cancer). The researchers analysed dietary data that was collected every 2 to 4 years from two large cohort studies. The studies lasted 24 to 26 years, from the 1980s to 2010, and included a total of 105,432 men and women. In addition to filling out periodic food surveys, participants self-reported occurences of melanoma, which the researchers confirmed by looking at their medical records. There were 1,840 confirmed occurrences of melanoma in the two studies. After adjusting for various risk factors, here is what the researchers found:

• People who consumed citrus two to four times per week had a 10% higher risk of melanoma than those who consumed citrus less than twice per week.
• People who consumed citrus more than one and a half times per day had a 36% higher risk of melanoma than those who consumed citrus less than twice per week.
• Grapefruit had the strongest association with melanoma of all the citrus fruits: people who consumed grapefruit three or more times per week had a 41% higher risk of melanoma than those who never consumed grapefruit.

While this study may have some intriguing findings, don’t give up your morning O.J. just yet. The study is observational and therefore cannot establish that high citrus intake causes melanoma. Additionally, citrus fruits can be an important contributor to overall health, and previous research has even associated citrus consumption with a lower risk of the same kind of melanoma. In the end, as one of the researchers stated, regardless of how much citrus you eat, you should always use sunscreen, hats, and cover-ups to protect against excessive sun exposure.

Source: Journal of Clinical Oncology