The authors of the study from Brown University, Rhode Island, also emphasize that citrus fruits are still considered healthy – but add that consumers should be aware that skin becomes more light-sensitive after consumption.
In the study published in the Journal of Clinical Oncology, US researchers found that white people who consumed large amounts of grapefruit or orange juice had ‘a small but significantly higher’ risk of malignant melanoma.
Researchers suggest a further area of research will be to see if the certain compounds can be removed from orange juice.
Important for vit C
Psoralens, compounds abundant in citrus fruits, are already known to increase sensitivity to light exposure. The US study examined whether citrus consumption could present a risk to health.
A high intake of grapefruit, and to a lesser extent orange juice, was associated with a higher risk of malignant melanoma.
Abrar Qureshi, one of the authors of the study, said, “This work does not indicate that we are concerned about citrus consumption. In fact citrus consumption is very important for vitamin C and other very healthy attributes.
“However, people need to be aware that when they are consuming certain fruits and vegetables that contain these photoactive compounds, they need to be more careful with their sun exposure the next few hours in particular and probably the next day or two.”
For those who eat a lot of citrus fruit, researchers advise the usual sun protection guidelines should apply: wearing sunscreen above SPF 30 which covers UVA and UVB radiation, hats, and clothing.
Cutaneous malignant melanoma is the fifth most common cancer in the US, and the sixth most common worldwide.
Other foods aside from citrus fruits contain psoralen, and Qureshi says one area of further research is to investigate other food types that may be associated with a risk of skin cancer.
“The work we’re doing at the biologic level is trying to understand which particular types of these compounds are the causative agents in promoting the development of skin cancer. There is a lot more to come. Maybe we can find a way to remove it safely from orange juice,” he added.
“No changes to orange juice consumption warranted,” says FDOC
The Florida Department of Citrus (FDOC) has raised concerns that sensationalist headlines in the media may mislead consumers.
“We support commentary by the researchers, as well as third party experts (including the American Society of Clinical Oncology) that these findings do not warrant any changes to grapefruit or orange juice consumption recommendations,” said David Steele, a FDOC spokesperson.
Orange juice is a good source of vitamin C, potassium, folate, thiamine, and is associated with a number of nutrition and health benefits, he added.
The FDOC emphasises that the study only establishes a link, which is different to a cause.
“Careless coverage [of the study] can leave people with incorrect impressions of the science involved,” added Steele.
He also notes the study has some limitations.
“Benefits of fruit juice shouldn’t be overlooked,” says NHS
Responding to the report, the UK’s National Health Service (NHS) website says: “The US study did find a small increase in the risk of melanoma, but the benefits of unsweetened fruit juice shouldn’t be overlooked.
“These findings do appear to find a link between citrus fruit and skin cancer risk. But this type of study cannot prove cause and effect.”
One 150ml glass of orange juice counts as one of the five portions of fruit and vegetables recommended a day.
People who consumed overall citrus 1.6 or more times a day had a 36% higher risk compared to those who consumed citrus less than twice a week, said researchers.
However, while grapefruit and orange juice had an association with melanoma risk, oranges and grapefruit juice did not.
Researchers suggest this is because concentrations of photoactive compounds vary in different parts of different fruits.
Source: Journal of Clinical Oncology, published online before print, June 29, 2015. doi:10.1200/JCO.2014.57.4111
Title: 'Citrus Consumption and the Risk of Cutaneous Malignant Melanoma'
Authors: S. Wu, J. Han, D. Feskanich, E. Cho, M. Stampfer, W. Willett, A. Qureshi.