Most skin cancer is caused by ultraviolet (UV) light damaging the DNA in skin cells, but now a new study has claimed that eating fish could increase a person's risk of melanoma.
The US study, from Brown University, found that people whose typical intake of fish was 300g per week had a 22% higher risk of developing a malignant melanoma than those who typical fish intake was less.
A melanoma is a potentially serious type of cancer which there is an uncontrolled growth of pigment cells.
In the study, 491,367 adults with an average age of 62 answered questions pertaining to their fish intake. This included those who ate fried, non-fried fish or tuna during the previous year as well as their portion sizes.
The frequency of new melanoma cases which developed over 15 years using data from cancer registries was then calculated.
Researchers also took into account factors which could influence the results such as person’s weight, whether they smoked or drank alcohol, their diet, family history of cancer and average UV radiation levels.
It found that overall, 1% developed malignant melanoma during the study and 0.7% developed stage 0 melanoma.
It concluded that total fish intake was linked to higher risks of potential skin cancer. Other results from the study included those who ate non-fried fish having an 18% higher risk of malignant melanoma and a 25% higher risk of stage 0 melanoma.
Those who consumed tuna had a 20% higher risk of malignant melanoma. Surprisingly those who consumed fried fish and no significant link with skin cancer.
Study author Eunyoung Cho said of the results: “Melanoma is the fifth most common cancer in the USA and the risk of developing melanoma over a lifetime is one in 38 for white people and one in 1,000 for black people.
“Although fish intake has increased in the USA and Europe in recent decades, the results of previous studies investigating associations between fish intake and melanoma risk have been consistent.
“This study has identified an association that requires further investigation.”
Other studies have found that people who eat more fish have higher levels of heavy metals in the body such as mercury and arsenic.
These contaminants are also associated with a higher risk of skin cancer.
This new research is bound to cause a lot of confusion for many as fish as always been hailed one of the healthiest food types.
“I wouldn’t discourage people from having fish just because of our finding,” Dr Cho added.
The British Nutrition Foundation added further comments regarding this study.
The said: "The recent paper by Li and colleagues describes analysis of data from a large number of subjects followed over a long period of time.
"The authors report a positive association between higher intakes of total fish, tuna and non-fried fish and risk of malignant melanoma and melanoma in situ after adjusting for age, sex and other factors. Individuals with a history of cancer or cancer diagnosis at baseline were excluded.
"The authors propose that contaminants present in fish may explain their findings, although levels of contaminants in the subjects’ bodies were not measured and so this proposed explanation cannot be supported by the evidence presented in this study."
Contrary to this study, the NHS says that a "healthy, balanced diet should include at least two portions of fish a week, including one of oily fish".
However, for certain types of fish, there are recommendations about the maximum we should eat.
You can find out more on the NHS website.
You should see a GP if you notice any changes to your skin, particularly your moles.
