Higher Orange Consumption Linked To Increased Risk of Melanoma, New Study Suggests

Higher Orange Consumption Linked To Increased Risk of Melanoma, New Study Suggests  

Peer Reviewed | Observational study | Humans

Individuals who consume more citrus fruit, especially oranges and orange juice, are at higher risk of melanoma compared to those with no consumption, according to research published in the British Journal of Dermatology. Findings suggest that consuming more than two servings of citrus a day is associated with a 63% increased risk of melanoma, relative to those with no consumption.

The researchers, from Indiana University, investigated the association between citrus consumption and melanoma, whilst taking into account a number of other factors which are already known to be risk factors for the disease, such as age, tanning habits, and having fair skin.

Using data from the UK Biobank, the researchers were able to review a large sample of 198,964 people, made up of 1,592 people with a melanoma diagnosis and 197,372 controls. Citrus intake data was collected via five rounds of questionnaires, asking participants to recall their citrus intake over the previous 24 hours.

Furthermore, the study found that consumption of oranges was independently associated with an increased risk of melanoma, relative to those with no consumption. The research found that those consuming more than one serving of oranges per day had a 79% increased risk for melanoma compared to those with no consumption and 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.

Dr Andrew R. Marley, lead author of the research, said:

“Psoralen has known photosensitising and photocarcinogenic properties and is found in abundance in citrus products. 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.”

Harriet Dalwood of the British Association of Dermatologists, said:

“As melanoma rates continue to rise, improved prevention strategies are needed. Research into contributing factors, such as citrus consumption, are useful in reducing skin cancer rates, particularly amongst those most at risk.

“Citrus fruits, especially oranges and orange juice, are consumed widely in the UK, with fruit juice consumption reported to be increasing year-on-year. This research could help medical professionals better advise patients who already have established risk factors such as a family history of melanoma to lower their citrus intake.”

Previous studies in this area have yielded inconsistent results and have been subject to limitations in their sample pools. For example, the Nurses’ Health Study and Health Professionals Follow-Up Study consisted of health care professionals who would have greater knowledge of UV protection, and the Women’s Health Initiative study, which found there was no significant association between citrus and melanoma risk, could be due to the postmenopausal respondents, who typically are less likely than younger women to engage in certain melanoma-risk behaviours.

There are around 16,200 cases of melanoma in the UK every year, this represents a 135% increase in annual melanoma cases since the early 1990s. It is the 5^th most common cancer diagnosis among UK residents and is growing in incidence faster than any other cancer.

The researchers acknowledge the study’s limitations, including the reliance on self-reported citrus consumption data. Results were further limited due to inability to control for unmeasured confounding factors, such as family history of melanoma.

Dr. Xin Li, senior author of the research, said:

"Despite our study limitations, we leveraged data from a large, population-based sample and we were able to control for several key sociodemographic and skin cancer-related variables. We believe that these results, based on biological plausibility, provide evidence in support of an association between high citrus consumption and melanoma risk."