A new study suggests that eating two portions of fish each week is linked to an increased risk of skin cancer. The NIH-AARP Diet and Health Study by Brown University found that typical daily intake of fish of 42.8g (equivalent to about 300g per week) had a 22 per cent higher risk of malignant melanoma compared to daily fish intake of 3.2 grams.
Published in the journal Cancer Causes and Control, the findings — based on a study of 4,91,367 US adults — suggested that eating more fish also increased the risk of developing abnormal cells in the outer layer of the skin only, which is known as stage 0 melanoma or melanoma in situ (also sometimes referred to as pre-cancer), one of the most common skin cancers.
So, is eating fish not advisable?
“Fish is said to be a source of omega-3 fatty acids and vitamins such as D and B2 (riboflavin),” said Dr Niti Raizada, director – Medical Oncology and Hemato-Oncology, Fortis Hospitals, Bangalore. Fish is also rich in calcium and phosphorus and a great source of minerals, such as iron, zinc, iodine, magnesium, and potassium.
Additionally, the American Heart Association recommends eating fish at least two times per week as part of a healthy diet.
“We speculate that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic and mercury,” author Eunyoung Cho said, as per The Independent.
Notably, prior epidemiological studies evaluating the association between fish intake and melanoma risk have been few and inconsistent. Few studies distinguished different types of fish intake with risk of melanoma.
In general, while the exact cause of all melanomas isn’t clear, but exposure to ultraviolet (UV) radiation from sunlight increases your risk of developing melanoma, said Dr Raizada.
How is fish consumption related to skin cancer?
According Dr Hitesh R Singhavi, consultant-head and neck, Onco Surgery, Fortis Hospital Mulund, since frying process drastically reduces omega-3 fatty acids in fish, which is the primary source of its nutritional power, it is possible that daily consumption of fish might not have such good nutritional value. “However, this data is still inconclusive as factors like the type of fish and cooking method can impact the overall risk factors,” Dr Singhavi said.
Experts also suggest that discontinuing fish intake is not recommended. “I don’t think the study can be applied to pigmented skin like that of Indians and Asians. Many people, especially in the Eastern part of the country, have been having fish for long. We have not had higher chances of melanoma due to fish till date,” explained Dr Rinky Kapoor, consultant dermatologist, cosmetic dermatologist and dermato-surgeon, The Esthetic Clinics.