Often lauded as a superfood, fish has its clear dietary advantages, providing the body with vital fatty acids and vitamins.
Nevertheless, an excessive amount of fish could well be a nasty thing. In response to a recent study, eating two portions per week – as really helpful by the NHS – has been linked to an increased risk of skin cancer, probably the most deadly of its kind.
In the brand new research, experts from Brown University found that folks whose typical every day intake of fish was 42.8g (reminiscent of about 300g per week) had a 22 per cent higher risk of malignant melanoma than those whose typical every day fish intake was just 3.2g.
Those eating more fish also had a 28 per cent increased risk of developing abnormal cells within the outer layer of the skin only – referred to as stage 0 melanoma or melanoma in situ (also sometimes known as pre-cancer).
The findings were based on a study of 491,367 US adults and published within the journal Cancer Causes & Control.
Creator Eunyoung Cho said the research has “identified an association that requires further investigation.
“We speculate that our findings could possibly be attributed to contaminants in fish, corresponding to polychlorinated biphenyls, dioxins, arsenic and mercury.”
Other experts said fish was a very important healthy food and there was no have to stop eating it.
Dr Duane Mellor, senior lecturer at Aston Medical School, said: “The authors suggest that there could possibly be a link between contaminants within the fish which could increase risk of cancer, but that is more likely to affect the chance of greater than just skin cancers.
“This study doesn’t have a transparent mechanism of how fish intake could increase risk of melanoma – there is no such thing as a clear evidence that eating fish can result in an increased risk of developing skin cancer.
“It is vital to recollect eating two portions of fish per week … could be a way of including vital nutrients corresponding to omega-3 fatty acids as a part of a healthy eating regimen and this study mustn’t discourage people from including fish as a part of a healthy eating regimen.”
Those within the study were aged 62 years on average and reported how often they ate fried fish, non-fried fish, and tuna in the course of the previous 12 months in addition to their portion sizes.
The researchers then calculated the frequency of recent melanoma cases that developed over 15 years using data obtained from cancer registries.
They took under consideration aspects that would influence the outcomes, corresponding to people’s weight, whether or not they smoked or drank alcohol, eating regimen, family history of cancer and average UV radiation levels of their local area (to take account of exposure to the sun – a known risk factor for skin cancer).
Overall, 5,034 people (1 per cent) developed malignant melanoma in the course of the study period and three,284 (0.7 per cent) developed stage 0 melanoma. A breakdown of the outcomes showed that total fish intake was linked to higher risks.
Meanwhile, people whose typical every day tuna intake was 14.2g had a 20 per cent higher risk of malignant melanoma compared with those with a typical intake of 0.3g.
Eating 17.8g of non-fried fish per day was related to an 18 per cent higher risk of malignant melanoma and a 25 per cent higher risk of stage 0 melanoma, compared with eating just 0.3g.
Nevertheless, no significant link was found between eating fried fish and skin cancer.
Also, average every day fish intake was calculated originally of the study and should not represent how much people eat over the course of their lives.
Dr Michael Jones, senior staff scientist in genetics and epidemiology on the Institute of Cancer Research, London, said: “The authors found the next intake of non-fried fish and tuna was related to melanoma. These results were statistically significant and subsequently unlikely resulting from probability.
“It is feasible individuals who intake more non-fried fish or tuna produce other lifestyle habits that increase their risk of melanoma. The authors considered this and adjusted for some potentially confounding aspects.
“Nevertheless, because the authors acknowledge, that is an observational study (not a randomised trial) and it is feasible there are (known and unknown) aspects that the authors didn’t adjust for, or adjust for sufficiently.
“The authors speculate that the association could also be possibly resulting from contaminants in fish, but they didn’t measure levels of those contaminants within the participants.
“A general healthy balanced eating regimen should include fish and the outcomes from this study don’t change that suggestion.”