The incidence of black skin cancer is steadily increasing. A new study from the USA now shows a connection between the consumption of fish and the risk of developing malignant melanoma.

More than 230,000 people in Germany develop skin cancer every year – the majority of them white skin cancer, which is considered to be easily treatable. Black skin cancer, on the other hand, also known as malignant melanoma, is based on a degeneration of the pigment cells in the skin. The chances of recovery are significantly lower here than with white skin cancer – depending on the thickness of the tumor and the stage of the disease.

In addition to genetic predisposition and strong, unprotected UV exposure to sun rays or visits to solariums, nutrition also plays a role in the risk of skin cancer that should not be underestimated. A new US study has identified another risk factor in terms of nutrition – and has shown a connection between the development of melanoma and the consumption of fish.

As part of the study, the scientists examined data from more than 490,000 healthy people collected as part of the National Cancer Institute’s NIH-AARP Diet and Health Study over a period of more than 15 years.

At the beginning of the data collection, the subjects – on average 62 years old – provided information about their fish consumption. The researchers differentiated between raw and cooked fish, the respective frequency of consumption and the portion size. The aim was to identify a connection between the consumption of fish and the subsequent occurrence of skin cancer.

A total of 5,034 subjects developed black skin cancer during the study period, and a so-called melanoma in situ was found in 3,284 cases. This is an early form of black skin cancer that has not yet spread beyond the point of origin and has not yet broken through the basement membrane of the skin.

Individual factors of the subjects were also taken into account in the investigations. These include:

The researchers examined the connection between fish consumption and the risk of skin cancer using various groups of subjects. It turned out that those who consumed higher amounts also had a higher risk.

The risks were even higher in the group of subjects who consumed raw fish:

All about our largest organ – Yael Adler

The authors of the study assume that the results are due to pollutants in the fish such as polychlorinated biphenyls, dioxins, arsenic and mercury. “Previous research has found that higher fish consumption is associated with higher levels of these compounds in the body and has found an association between them and a higher risk of skin cancer,” the researchers write.

However, further studies are needed to identify the triggering amount and type of potentially carcinogenic pollutants. In addition, the scientists disclose existing weaknesses in the study that was carried out.

Some risk factors, such as the amount of birthmarks, hair color, frequency of severe sunburn and exposure to the sun, were poorly addressed. The researchers were also unaware of the development of individual fish consumption over the 15-year study period.

The reason for the increased mercury content in some fish species – primarily tuna, salmon, cod and swordfish – is the increased pollution of the world’s oceans. Overfishing in combination with climate change also play a role. This is confirmed by a study from 2019, which was published in the science magazine nature.

Pregnant women in particular should therefore be cautious when consuming fish and avoid particularly contaminated fish species such as tuna. Because mercury in particular can endanger the health of unborn children.