Eating 2 servings of fish per week linked to increased skin cancer risk, study suggests

Eating 2 servings of fish per week linked to increased skin cancer risk, study suggests
Elena Pejchinova/Getty Images
  • Eating more fish may be linked to higher risk of skin cancer, according to new research.
  • Fish such as tuna contain toxic mercury, arsenic, and other chemicals linked to cancer.

Eating fish frequently may be linked to higher risk of skin cancer, possibly due to contaminants in common types of fish like tuna, according to a study published June 9 in the journal Cancer Causes and Control.

Researchers from Brown University and the National Cancer Institute looked at data from 491, 367 older Americans, aged 50-71, over 15 years of follow-up to see how many of them developed melanoma, an aggressive form of skin cancer. The researchers compared melanoma rates with participants' dietary habits to see if there was a link between cancer risk and eating fish, which previous research has suggested.

They found that people who ate about two servings of fish per week, on average, had a 22% higher risk of developing melanoma, and a 28% higher risk of developing abnormal skin cells that can be a precursor to cancer, than people who ate less than half a serving.

For tuna specifically, people who ate about 3/4 of a serving per week had 20% higher risk of melanoma, compared to people who ate almost none.

While the findings suggest a link between eating more fish and skin cancer risk, researchers don't recommend changing your seafood habits just yet. More research is needed to clarify the link and potential risk factors, and fish is linked to health benefits like balancing blood sugar and lowering cholesterol.


Fish can be part of a healthy diet, but contaminants are a concern

It's not likely that fish itself is linked to cancer risk, but rather the contaminants in the fish, including arsenic and mercury, according to Eunyoung Cho, co-author of the study and associate professor of dermatology and epidemiology at Brown University. Previous research has found high levels of mercury in the human body are associated with higher risk of skin cancer, and fish consumption is linked to a higher burden of these toxins in the body.

"Mercury consumption in the U.S. is mostly from fish," Cho said in a press release. "So if mercury is related to skin cancer, then it stands to reason that fish intake may be related, too."

However, other previous research has found eating more fish has no effect on skin cancer risk, or may even be protective. It's also linked to and reduced the risk of other cancers, such as bowel cancer.

There's plenty of other good reasons to include fish in your diet, too. Fish is a rich source of important nutrients, including protein, omega-3 fatty acids and B vitamins.

It's also plays a major role in the Mediterranean diet and Blue Zones diet, both considered among the healthiest ways to eat.


Current dietary guidelines and advice from the FDA recommend eating fish in moderation — about eight ounces, or a serving and a half, per week, and sticking to types of fish lower in mercury, including small, oily fish like sardines and anchovies.