An estimated 20 percent of Americans will develop skin cancer by their 70th birthday, making it the most common cancer in the U.S. However, it’s also one of the most preventable types of cancer. Things like limiting your sun exposure, always wearing sunscreen, covering up when possible, and avoiding tanning beds are all good ways to protect your skin, as your dermatologist has likely cautioned you. Monthly self-checks to identify any new or questionable moles or growths are also highly recommended. But preventing skin cancer goes beyond the surface, and what you eat can also play a role. Read on to discover which specific food—usually considered to be healthy—has been linked to a higher risk for developing skin cancer.

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Various foods can impact your skin cancer risk.

While there’s no magic pill or supplement you can take to prevent skin cancer, certain foods have been shown to decrease your risk of the disease. “There are definitely foods that we eat that can boost our ability to protect our skin from the sun,” Patricia Farris, MD, a dermatologist and fellow of the American Academy of Dermatology, told CNN.

Foods like tomatoes and watermelon are rich in lycopene—an antioxidant that’s been found to help protect against sunburns. Beta carotene, which we get from fruits and vegetables like carrots, sweet potatoes, and mangoes, is converted into vitamin A in the body and can also help reduce sun sensitivity.

One food, however, may actually be sabotaging your skin’s health when eaten too frequently—even though it’s known for having a multitude of other health benefits.

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This popular food may increase your risk of melanoma.

A June 2022 study published in Cancer Causes&Control found a positive link between eating fish—specifically non-fried fish and tuna—and the risk of developing melanoma, which is the deadliest type of skin cancer.

The study included 491,367 Americans ages 50-71 who were part of the NIH-AARP Diet and Health Study—a research collaboration that began in the 1990s with the goal of examining the link between diet and cancer. Participants recorded their fish intake over the course of 15 years. The group who reported eating the most fish—an average of about 14 grams per day—were 20 percent more likely to develop malignant melanoma.

Various toxins found in fish are likely to blame.

Fish can absorb toxic chemicals from the water they live in, and when humans frequently consume contaminated fish over a long period of time, the health risks can be considerable. Authors of the new study believe this could have had a significant impact on their results.

“We speculate that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic, and mercury,” one of the study’s co-authors, Eunyoung Cho, said in a statement. “Previous research has found that higher fish intake is associated with higher levels of these contaminants within the body and has identified associations between these contaminants and a higher risk of skin cancer.”

It’s important to note that the study did not specifically measure or investigate levels of mercury or other toxins in participants, so further research is needed.

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Don’t swear off fish just yet.

The study proved to have other limitations as well. While it accounted for various demographic and lifestyle factors—including body mass index, physical activity, intake of alcohol and caffeine, smoking, family history of cancer, and estimated UV levels—it fell short in other areas.

“The investigators unfortunately did not account for many established risk factors, such as number of moles, hair color—red hair is an important one—number of past burns, or sun-protective behaviors, which really impair our ability to interpret this data,” dermatologist Adam Friedman, MD, told Today.

Until more studies are conducted on the topic, it seems that the health benefits of fish might outweigh the drawbacks. To be safe, however, the recommendation set by the FDA of 8 ounces of fish per week is a good guideline for consumption.