What you may have heard
Frequent consumption of fish can put you at a higher risk of developing melanoma.
What the science tells us
Fish is widely recommended in dietary guidelines as a valuable source of protein, heart-healthy omega-3 fatty acids, and other essential nutrients. Despite these benefits, some studies have explored a possible link between fish consumption and melanoma, a serious type of skin cancer. Environmental contaminants found in certain fish may play a role, but the relationship is complex and not yet fully understood.
Epidemiological Evidence
In an observational study, researchers from Brown University followed nearly 500,000 individuals for over 15 years. They found that those who reported eating the most fish had a 22% higher risk of developing melanoma than those who ate the least fish (Li et al.). This association was consistent for total fish intake, tuna, and non-fried fish, and was observed for both malignant and in situ melanomas.
The increased risk may be related to contaminants in fish, such as mercury, PCBs (polychlorinated biphenyls), and other environmental toxins. While this study indicates a potential link, it does not prove that fish consumption causes melanoma. Further research is needed to better understand this relationship.
Laboratory Evidence/Supporting Evidence
There is currently no laboratory research regarding fish consumption and melanoma.
How to reduce your risk
The American Cancer Society continues to recommend fish as part of a healthy diet. However, if you are concerned about the risks associated with melanoma:
- opt for fish with lower levels of mercury (e.g., salmon, sardines, clams);
- focus on sun protection by limiting exposure and using sunscreen (spf ≥ 30) regularly.
Bottom line
Some research has raised questions about a link between fish and melanoma, but the evidence is not currently strong enough to change dietary guidelines. Fish remains a nutritious choice, especially when you choose low-mercury options. The most effective way to reduce your risk of melanoma is by protecting your skin from the sun.