New Study Finds A Link Between Tuna And Increased Cancer Risk

Tuna is famously praised as the superstar of a healthy lunch. It promotes heart health, lowers bad cholesterol levels and blood pressure, and is even thought to have anticancer properties, per Organic Facts. However, a recent study published in the journal Cancer Causes & Control proposes that the opposite might be true.

According to the Mayo Clinic, melanoma is the most threatening type of skin cancer. It typically develops in the outermost layer of the skin in cells called melanocytes – which produce the melanin that gives skin its color. The American Cancer Society reports the risk of developing melanoma is 1 in 38 for white people, 1 in 1,000 for Black people, and 1 in 167 for Hispanic people.

Overexposure to the ultraviolet rays of the sun or having "problem moles" have been commonly considered the biggest causes of melanoma. But, according to the study by researchers from Brown University, there might be another, more insidious risk factor for developing melanoma — and there's a good chance you have a can of it in your pantry right now.

The study in Cancer Causes & Control found that eating large amounts of fish (including tuna) might be directly correlated with an increased risk of malignant melanoma, via Springer. The researchers took into account a variety of confounding variables, including subjects' BMI, normal level of physical activity, family history of cancer, and the average UV ray levels in their geographic location. Subjects who consumed 42.8 grams of fish were at a 28% higher risk of developing melanoma compared to subjects who consumed 3.2 grams. For reference, the standard portion size of a single serving of fish is roughly 6 ounces or 170 grams, according to the Washington State Department of Health. A normal can of Starkist chunk light tuna you'll find at your grocery store is 5 ounces.

But, although these results spark an important conversation, they shouldn't be considered definitively conclusive yet. Eunyoung Cho, associate professor of dermatology and epidemiology at Brown University and the study's corresponding author, said, "We speculate that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic and mercury," adding, "However, we note that our study did not investigate the concentrations of these contaminants in participants' bodies and so further research is needed to confirm this relationship."

Still, it might be worth thinking twice about that tuna salad in your lunch box.