Just in time for summer heat waves, new research linking citrus fruits to malignant melanoma unleashed a slew of overheated headlines on the Internet. The increased cancer risk may be due to certain photosensitizing compounds known to be in citrus fruits.
But cooler heads are saying that the modest increase in melanoma risk seen in the study is probably not enough to forsake the benefits of including oranges, lemons, limes and grapefruit in a healthy diet.
Compounds called psoralens occur naturally in citrus fruits. Clinically, they’re used to sensitize skin to ultraviolet (UV) radiation in preparation for treatment of severe cases of psoriasis and other skin disorders. For the same reason, they were also used as “tanning activators” in suntan lotions and sunscreens. By 1996 the practice ended, after it had become apparent that people using sunscreens containing psoralens had about four times the risk of developing melanoma than those who didn’t.
Could people who have a taste for citrus be subjecting themselves to similar danger? A team of researchers from the Warren Alpert Medical School of Brown University in Providence, RI, investigated the possibility.
The citrus-melanoma link
The team analyzed diet, lifestyle and health data from 63,810 women participating in the Nurses’ Health Study between 1984 and 2010. The same data was collected from 41,622 men participating in the Health Professionals Follow-Up Study between 1986 and 2010. After tracking their health for up to 26 years, it was revealed that 1,840 participants were diagnosed with melanoma.
Their analysis, published in the Journal of Clinical Oncology, showed a dose-response relationship between melanoma risk and citrus consumption. That is, the more servings of citrus fruits or juices participants reported consuming, the higher their risk of melanoma. For example, consumption of fruits or juices at least 1.6 times a day was linked to 36 percent higher melanoma risk.
Drinking orange juice was associated with the greatest risk, which the researchers attribute to the popularity of the product. Eating whole grapefruit was also strongly associated with melanoma risk for people who experienced severe sunburns as children and those who receive a lot of UV exposure. Strangely enough, the link between eating oranges or drinking grapefruit juice and melanoma wasn’t statistically significant.
Time to quit citrus?
The American Cancer Society estimates that 73,870 people in the US will be diagnosed with melanoma in 2015. Nearly 10,000 people will die from the disease. The number one risk factor for melanoma is exposure to ultraviolet radiation, either from the sun or from tanning beds.
Should you be thinking about cutting back on your citrus as the mercury climbs? F. Perry Wilson, MD, MSCE, is an analyst who brings research hype back down to earth in “Analysis in 150 Seconds,” a video series for MedPage Today. According to Dr. Wilson, when you compare the degree of risk found in the study with actual melanoma cases, giving up the health benefits of drinking orange juice to avoid skin cancer may not be worth it.
Chill out and pass the sunscreen
“We’re talking seven cases per 10,000 people per year,” Wilson said. “To prevent just one of those cases, you would need to convince roughly 2,500 people who were high-citrus eaters to stop eating citrus. Compare that with the roughly 150 people you would need to convince to wear sunscreen to prevent a case of melanoma.”
The takeaway from this study: keep enjoying your citrus and try to eat at least five servings of fruits and vegetables every day. Using plenty of sunscreen this summer is still your best way to avoid boosting your risk for melanoma.
Medical News Today