A preliminary study into the risks associated with citrus consumption and melanoma risk has discovered some troubling connections.
Over a period of 25 years, researchers observed the diets of more than 100,000 people and their self-reported health events, including skin cancer. Participants were asked to carefully monitor how much citrus they consumed –– including grapefruit, oranges and associated juices. Over the decades, they noted that 1,840 of the study participants developed melanoma, with those who consumed citrus fruit 1.6 times daily (the equivalent of a whole grapefruit or two 6-ounce glasses of orange juice), increasing their chance of developing melanoma by a whopping 36 percent.
Those who consumed citrus only two to four times per week had a 10 percent chance of skin cancer.
While the sun is still the main culprit when it comes to skin cancer, researchers believe that photoactive compounds contained in citrus fruits may make our skin more susceptible to UV radiation. Plants produce these organic compounds called furocoumarins as a defense mechanism against everything from mammals to insects.
(One extreme example of its toxicity can be found with giant hogsweed, an invasive plant currently spreading across New York state, whose furocoumarins-heavy sap can cause severe skin and eye irritation and even blindness with exposed to the sun.)
Based on this preliminary study, furocoumarins consumed via citrus fruits may be playing in a role in enhancing skin sun sensitivity and the spread of melanoma. The researchers admit, however, that such a link is tenuous and must be confirmed with further studies. At this time, there's absolutely no reason to eye grapefruit or oranges suspiciously.
"We are NOT recommending changing fruit consumption as these fruits and vegetables are important for overall health,” senior author Dr. Abrar Qureshi writes in the study. "However, until we learn more about these furocoumarins, those consuming fresh citrus fruits on a regular basis should be extra careful with sun exposure, and depending on their outdoor activities, they should wear appropriate sunscreen, hats and sun-protective clothing."
In addition, Dr. Walter Willett of the Harvard School of Public Health, who also worked on the study, urged people to embrace variety and not consume too much of any one thing.
"Variety is a good thing to have because it means that you are not likely to miss out on something important and it also means you not likely to miss out on something that is good for you," he told NBC News.
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