A diet rich in seafood is known to provide several health benefits. However, researchers of a recent study caution that they could raise your risk of exposure to environmental contaminants such as per- and polyfluoroalkyl substances (PFAS), also known as "forever chemicals".

The findings were based on a survey conducted among 1,829 New Hampshire residents regarding the consumption frequency, portion size, types, and sources of seafood among adults and children. Based on the survey results, the researchers sourced the most commonly consumed species such as cod, haddock, lobster, salmon, scallop, shrimp, and tuna from a seafood market in Portsmouth and quantified 26 PFAS compounds in them.

With the available health guidance values, the team then calculated hazard quotients to assess exposure risk from seafood consumption.

The results showed that shrimp and lobster had the highest concentrations of certain PFAS compounds, with averages ranging as high as 1.74 and 3.30 nanograms per gram of flesh, respectively. The levels of individual PFAS were less than one nanogram per gram in other fish and seafood.

High levels of PFAS are linked to health hazards, including reduced immunity, decreased fertility, developmental delays in children, and increased risk of certain cancers.

"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. Understanding this risk-benefit trade-off for seafood consumption is important for people making decisions about diet, especially for vulnerable populations such as pregnant people and children," Megan Romano, the study's corresponding author from Geisel School of Medicine, said in a news release.

The consumption pattern showed that men in New Hampshire ate just over one ounce of seafood per day, while women ate just under one ounce. Both these values are higher than the national average consumption of seafood. The children aged 2 to 11 years old in New Hampshire consumed about 0.2 ounces, which is the highest end of the range for children nationwide.

"Most existing research focuses on PFAS levels in freshwater species, which are not what people primarily eat. We saw that as a knowledge gap in the literature, especially for a New England state where we know people love their seafood," Romano said.

The survey also revealed an uneven consumption pattern in New Hampshire, with more than half of the individuals who consumed seafood in the week before the survey residing either along the state's coastline or near the border with Massachusetts. The consumption was more in households with income below $45,000 per year.

While there are Federal guidelines for safe seafood consumption for mercury and other contaminants, there are none for PFAS, Celia Chen, a co-author of the study from Dartmouth College, said.

"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. But it's less clear for PFAS, especially if you start looking at how the different compounds behave in the environment," Chen added.

According to Kathryn Crawford, the study's first author from Middlebury College, establishing safety guidelines would help protect people who are especially susceptible to pollutants.

"Seafood consumption advisories often provide advice for those individuals that is more conservative than for the rest of the population. People who eat a balanced diet with more typical, moderate amounts of seafood should be able to enjoy the health benefits of seafood without excessive risk of PFAS exposure," Crawford said.

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