A new study from Brown University, published in Cancer Causes & Control (2022; 33:921–928) appears to demonstrate a link between higher fish consumption and an increased risk of developing melanoma. The researchers suggest that bio-contaminants in water, such as mercury, are probable factors responsible for this increased risk.
The size of the study—it included 491,367 adults with an average age of 62 years—imparts a degree of significance to the study results, the authors say. They utilized data from the U.S. National Cancer Institute’s NIH-AARP Diet and Health Study between 1995 and 1996 and calculated the incidence of new melanomas that developed over a median period of 15 years using information obtained from cancer registries. During the data gathering process, participants reported how frequently they ate fried fish, non-fried fish and tuna during the previous year, as well as the portion sizes they consumed.
The authors report that a total of 5,034 participants (1%) developed malignant melanoma and 3,284 (0.7%) developed stage 0 melanoma (or melanoma in situ). A higher intake of non-fried fish and tuna was associated with increased risks of malignant melanoma and stage 0 melanoma.
People with a median daily intake of 42.8 grams of fish demonstrated a 22% higher risk of malignant melanoma and a 28% increased risk of developing stage 0 cancer, compared to people with a median daily fish intake of 3.2 grams. (According to the authors, a regular serving of cooked fish is approximately 140 to 170 grams; a can of tuna is 142 grams.)
“This study is important because it’s very large and it’s prospective by design, meaning that fish intake was assessed before the development of cancer,” said author Eunyoung Cho, an Associate Professor and Director of Research in the Department of Dermatology at the Warren Alpert Medical School of Brown University, in a press release.
“Although fish intake has increased in the U.S. and Europe in recent decades, the results of previous studies investigating associations between fish intake and melanoma risk have been inconsistent — our findings have identified an association that requires further investigation,” she said.