It’s very natural to want to be in the sun. What’s unnatural is when we’re indoors all week and then stay outdoors all weekend. This increasingly common lifestyle puts us at higher risk for skin cancer….
—Marianne Berwick, PhD, MPH
Could too much citrus cause skin cancer?” was the lead-in of an NBC News item about a study linking consumption of grapefruits and oranges to an increased risk of melanoma.1 “Citrus consumption and skin cancer: How real is the link?” was the question posed by a headline in The Washington Post.2 With such media coverage, patients may be questioning whether they should stop eating and/or drinking citrus products.
A study in the Journal of Clinical Oncology found a 36% higher risk of melanoma among those who consumed overall citrus items 1.6 times or more a day vs less than twice a week, but the study authors cautioned that “further investigation is needed to confirm our findings and explore related health implications.”3
Other researchers and clinicians have pointed out that the study results do no warrant abandoning grapefruit, oranges, or other citrus fruits and their juices. “I love grapefruits and grapefruit juice and oranges and orange juice and am continuing to eat them,” Marianne Berwick, PhD, MPH, Distinguished Professor, Department of Internal Medicine and Dermatology at the University of New Mexico, Albuquerque, told The ASCO Post.
In an editorial accompanying the study report in the Journal of Clinical Oncology, Dr. Berwick, wrote: “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.”4
Getting Full Benefit of Sunscreen
In a previous article from the University of New Mexico, Dr. Berwick acknowledged that being outdoors has beneficial mood and health effects, and “it’s very natural to want to be in the sun. What’s unnatural is when we’re indoors all week and then stay outdoors all weekend. This increasingly common lifestyle puts us at higher risk for skin cancer because of our skin’s intermittent exposure to the sun.”5
Protection from the sun should include seeking shade, wearing hats and protective clothing, and properly and adequately using sunscreen. “We don’t use enough sunscreen,” Dr. Berwick stated. “To get the full benefit, apply sunscreen half an hour before going out and then half an hour after being out. It’s very important that you reapply sunscreen every 2 hours or so while outside.”
Dangers of Indoor Tanning
Dr. Berwick implored people not to use tanning salons. “In some cases, tanning salons may be providing 10 times as much ultraviolet radiation as the sun,” Dr. Berwick told The ASCO Post, so those using such salons “are really dosing themselves.”
On a positive note, a recent research letter in JAMA Dermatology noted that use of indoor tanning among U.S. adults had dropped, with 1.6 million fewer women and 0.4 million fewer men using indoor tanning in 2013 than in 2010.6 This decrease “may be partly attributed to the increased awareness of its harms,” the authors wrote. “In addition, a 10% excise tax on indoor tanning was implemented in 2010, which may have contributed to the decrease in indoor tanning.”
Another research letter, however, noted that indoor tanning is common at places other than tanning salons, such as private homes and gyms. “Some indoor tanning users might seek out gyms to circumvent the federal tanning excise tax, which gyms are not required to collect. Nonsalon tanning locations also seem to attract more high-risk tanners (ie, those who are depressed or have a dependence on tanning),” the authors noted.7
The writers of both letters stressed the importance of physician counseling to reduce indoor tanning. ■
Disclosure: Dr. Berwick reported no potential conflicts of interest.
1. Fox M: Could too much citrus cause skin cancer? NBC News, June 29, 2015. Available at nbcnews.com. Accessed July 23, 2015.
3. Wu S, et al: Citrus consumption and risk of cutaneous malignant melanoma. J Clin Oncol 33:2500-2508, 2015.
4. Berwick M: Dietary advice for melanoma: Not ready for prime time. J Clin Oncol 33:2487-2488, 2015.
5. Frank L: Three questions for skin cancer investigator Dr. Marianne Berwick. University of New Mexico Health Sciences Center news release, May 1, 2014. Available at hscnews.unm.edu. Accessed July 23, 2015.
6. Guy GP Jr, et al: Recent changes in the prevalence of and factors associated with frequency of indoor tanning among US adults. JAMA Dermatol. July 1, 2015 (early release online).
7. Hillhouse J, et al: Prevalence and correlates of indoor tanning in nonsalon locations among a national sample of young women. JAMA Dermatol. June 24, 2015 (early release online).
A study finding a link between citrus consumption and increased risk of melanoma1 may provide food for thought about the findings and implications as well as whet the appetite for more evidence, but according to several experts commenting on the study, it does not mean you should stop eating citrus ...