New research from Indiana University has found that individuals who consume more citrus fruit, especially oranges and orange juice, are at higher risk of melanoma compared to those with no consumption.
Results of the study were published online ahead of print in the British Journal of Dermatology (Mar. 30, 2021).
“Psoralen has known photosensitizing and photocarcinogenic properties and is found in abundance in citrus products,” explained Dr. Andrew R. Marley, lead author of the research, in a press release. “This fact has spurred studies to investigate whether high citrus consumption is associated with melanoma risk due to psoralen photocarcinogenicity.
“This research suggests a significant increase in melanoma risk associated with a higher citrus intake and these findings could well shape sun-exposure guidance and how we approach advising patients that are already at high risk of developing melanoma.”
Dr. Marley is a pre-doctoral fellow in the Behavioral Oncology Training Program at the Indiana University Richard M. Fairbanks School of Public Health in Bloomington, Ind.
Researchers investigated the association between citrus consumption and melanoma, while also taking into account several factors that are already known to be risk factors for the disease such as age, tanning habits and having fair skin.
The study’s authors investigated data from the UK Biobank (UKBB) and reviewed a large sample of 198,964 people, which consisted of 1,592 patients with a melanoma diagnosis and 197,372 controls. Citrus intake data was collected using five rounds of questionnaires asking participants to recall their citrus intake over the previous 24 hours.
Investigators discovered that consumption of oranges was independently associated with an increased risk of melanoma, relative to those who had no consumption. The research found those consuming more than one serving of oranges per day had a 79% increased risk for melanoma compared to those with no consumption. Consuming more than one serving of orange juice increased the risk by 54%.
While a relationship between citrus consumption and melanoma risk was observed among this UKBB sample, participants with a fair or very fair skin complexion were found to be particularly at risk with higher citrus intake.
“We leveraged data from a large, population-based sample and we were able to control for several key sociodemographic and skin cancer-related variables,” said Dr. Xin Li, a senior author of the study and an assistant professor in the Department of Epidemiology and Biostatistics at the Indiana University School of Public Health. “We believe that these results, based on biological plausibility, provide evidence in support of an association between high citrus consumption and melanoma risk.”