Too Much Citrus May Boost Melanoma Risk
Oranges and grapefruit are beloved citrus fruits that seem to capture the bright essence of the tropical sun that sustains their growth. These sunny fruits burst with flavor and freshness, making them irresistible to most people. Older people on certain medications may need to avoid eating grapefruit, however, because it is notorious for interfering with an enzyme system in the liver that metabolizes certain drugs. Eating grapefruit or drinking grapefruit juice can affect how these drugs behave in the body, so they’re usually off the menu for anyone taking a cholesterol-lowering statin, drug, for example.
But now a large new analysis of dietary patterns suggests that eating oranges or grapefruit too often can have another unwanted side effect: an increased risk of developing melanoma, the most deadly form of skin cancer. This unexpected association arose after investigators examined data gathered from more than 100,000 Americans. People who consumed citrus fruit or juice at least 1.6 times daily were 36% more likely to be diagnosed with melanoma than people who only consumed citrus less than twice a week.
Eating or drinking these fruits or their juices was not linked to any other forms of skin cancer. While it might be tempting to speculate that people who consume these fruits more often are simply more likely to spend more time in the sun, researchers think there’s another, more direct explanation. These fruits are rich in compounds called furocoumarins, and furocoumarins have been shown to increase the skin’s sensitivity to the sun’s rays.
The association was strongest for grapefruit, and the increased risk of melanoma appeared to affect both men and women. It should also be noted that citrus consumption has been shown to provide health benefits in terms of coronary heart disease risk, cancer prevention, and overall health effects. So, don’t chop down your grapefruit tree just yet.
"While our findings suggest that people who consume large amounts of whole grapefruit or orange juice may be at increased risk for melanoma, we need much more research before any concrete recommendations can be made," said lead study author Shaowei Wu, PhD, a postdoctoral research fellow at the Department of Dermatology, Brown University in Providence, Rhode Island. "At this time, we don't advise that people cut back on citrus -- but those who consume a lot of grapefruit and/or orange juice should be particularly careful to avoid prolonged sun exposure.”
Marianne Berwick, PhD, MPH, professor of the Department of Internal Medicine and Dermatology at the University of New Mexico weighed in on this new finding, stating, "For people who would be considered at high risk, the best course might be to advise individuals to use multiple sources of fruit and juice in the diet and to use sun protection, particularly if one is sun sensitive.”
American Society of Clinical Oncology website. Press Center page. Accessed July 29, 2015 from: http://www.asco.org/press-center/citrus-fruit-consumption-may-be-associated-increased-melanoma-risk
S. Wu, J. Han, D. Feskanich, E. Cho, M. J. Stampfer, W. C. Willett, A. A. Qureshi. Citrus Consumption and Risk of Cutaneous Malignant Melanoma. Journal of Clinical Oncology, 2015; DOI: 10.1200/JCO.2014.57.4111