Seafood lovers warned of ‘increased risk’ of chemicals that cause cancer in new study

By Staff 8 Min Read

A new study has warned that people who eat lots of seafood may be increasing their risk of exposure to so-called ‘forever’ chemicals, which can cause cancer and other illnesses

Seafood lovers have been warned of an ‘increased risk’ of exposure to harmful chemicals that can cause cancer and other illnesses, according to a new study.

The research, conducted by the University of Dartmouth in the US, has revealed that fish contain higher levels of PFAS – damaging, man-made toxins which take thousands of years to degrade – than previously estimated. These PFAS chemicals, originating from sources such as packaging, clothing and fire-fighting foams, have been detected in drinking water before, with studies indicating that nearly all Americans have measurable amounts in their blood.

Excessive exposure to PFAS can result in health problems like cancer, foetal abnormalities, and liver disorders, hence it’s crucial to avoid high concentrations. This is particularly concerning for fans of lobster and shrimp, as these were found to have the highest concentrations of PFAS. However, other seafood enthusiasts should also be cautious, as previous levels of PFAS are believed to have been underestimated.

The study, published in the journal Exposure and Health, seems to challenge the widely held belief that diets rich in fish are purely beneficial. Previous studies have suggested that seafood helps regulate inflammation, reduces the risk of heart attacks and aids in weight loss.

The research team has emphasised that their findings should not deter people from eating fish. Instead, they suggest that public health officials should provide new guidelines detailing the safe consumption levels of seafood to limit exposure to PFAS (perfluoroalkyl and polyfluoroalkyl substances), reports Bristol Live.

The team conducted an analysis of PFAS concentrations in seafood and paired it with a survey of eating habits in New Hampshire, known for being one of the top fish-consuming states in the US. The researchers measured the levels of 26 types of PFAS in samples of the most popularly consumed fish species: cod, haddock, lobster, salmon, scallop, shrimp, and tuna.

They discovered that shrimp and lobster had the highest concentrations, with averages as high as 1.74 and 3.30 nanograms per gram of flesh. This could be due to these species’ habitat and feeding patterns on the seafloor, although the exact reasons are still uncertain. Other seafood concentrations were generally less than one nanogram per gram of flesh. The team then compared this data with the seafood consumption habits of people in New Hampshire to assess the risk and the results confirmed the state’s reputation as a haven for seafood lovers.

Men and women in New Hampshire were found to eat just over one and just under one ounce of seafood per day – both of which are more than one-and-a-half times the national average. Around 94 per cent of adults reported that they had consumed seafood in the last month, and more than two-thirds said they had eaten fish within the last week. The most popular types of seafood were salmon, shrimp, and haddock and people who ate fish the most lived on New Hampshire’s coast or near the border with Massachusetts.

Professor Megan Romano, corresponding author, said: “Our recommendation isn’t to not eat seafood. Seafood is a great source of lean protein and omega fatty acids, but it also is a potentially underestimated source of PFAS exposure in humans. Therefore, understanding this risk-benefit trade-off for seafood consumption is important for people making decisions about their diet, especially for vulnerable populations such as pregnant people and children.”

On the flip side, Professor Celia Chan, who co-authored the study, pointed out that while there are established guidelines for dodging mercury in seafood, we’re at sea when it comes to PFAS. “Top predator species such as tuna and sharks are known to contain high concentrations of mercury, so we can use that knowledge to limit exposure,” she explained. “But it’s less clear for PFAS, especially if you start looking at how the different compounds behave in the environment.”

However, study lead author Professor Kathyrn Crawford noted that the guidelines would primarily benefit those vulnerable to pollutants, rather than the general public. She said: “Most of the population, a.k.a. those who eat a balanced diet with typical, moderate amounts of seafood, should be able to enjoy the health benefits of fish without excessive risk of PFAS exposure.”

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