Fish and seafood consumption in the EU: awareness of dietary advice on mercury

The European Commission asked EFSA to carry out a survey across the EU, before and after some countries updated their advice on how often to eat fish and seafood that may contain traces of mercury. 

Examples of these species are large predator fish such as shark, swordfish, and tuna (bigeye and bluefin) because they feed on smaller fish, so the mercury accumulates in them over their lifespan. 
The Commission’s request was linked to discussions with EU Member States on the regulatory limits (called Maximum Levels or MLs) for mercury in different species of fish and seafood, and any future update of EFSA’s risk assessment of mercury in food.

An EU-wide survey

A first survey was conducted in all 27 EU member States, Iceland and Norway in April-May 2023. A second survey took place in 10 countries that updated their advice, plus another five countries that did not, to allow a comparison. 

The surveys included higher shares of pregnant (and lactating) women among the respondents because the foetus is the most at risk population from mercury but also acquires important nutrients from fish and seafood in the mother’s diet.  

Frequency of fish and seafood consumption

Sofia Ioannidou, a food consumption expert at EFSA and coordinator of the research, said: “60% of respondents surveyed in the 29 countries said they eat fish and seafood. Around one-third of those consumers - 34% of adolescents and adults, and 33% of pregnant women - said they consume fish species with the highest Maximum Levels for mercury contamination three or more times per week.

“While these findings are important, we explain in the report that they should be treated with caution due to uncertainties about the representativeness of the surveys.”

How much fish/seafood should people eat?

Most national authorities in the EU recommend 1-2 portions per week of fish and seafood species with higher mercury limits (1.0 mg/kg of fish wet weight), or 3-4 portions of species with lower mercury limits (0.5 mg/kg or 0.3 mg/kg of fish). Pregnant women are often advised to replace their intake of large fish with smaller fish containing less mercury. 

EFSA’s past scientific advice informed national dietary guidelines that aim to ensure that consumers, particularly pregnant women (and the developing foetus), can benefit from eating fish and seafood while keeping exposure to mercury as low as possible.

Health benefits include cognitive and immune function development in infants and reduced risk of cardiovascular disease for adults. On the other hand, exposure to methylmercury - the most hazardous form of mercury - is linked to reduced brain and neural development in the foetus and in young children.

Awareness of dietary advice

In a first for EFSA, the survey used social science methods to investigate consumer awareness of the advice and the associated benefits and risks.

Social scientist, Angela Bearth, is a member of EFSA’s Scientific Committee, and also part of the EFSA expert group on social research methods and advice that was responsible for the research on awareness.

She said: “While many consumers indicated in the survey that they had heard of the advice in their country and that they take it into account in their food choices, other factors such as taste, cost, and desire for a healthy diet drive changes in dietary habits more.

“This is a common phenomenon where survey respondents say one thing, but their behaviour indicates that other factors need taking into account.”

Knowledge of health benefits vs. risks

The survey tested respondents’ knowledge of several health benefits and risks linked to fish and seafood consumption, to estimate how well dietary advice might be understood and retained.
Dr Bearth stated: “Overall, more consumers (some 5 in 10) knew about health benefits than health risks (about 1 in 10), but mercury was the most widely recognised contaminant in these foods. The findings are consistent with past studies exploring this topic in European countries.”

Support to national authorities

The report shows important differences across countries and between the adolescent/adult population and pregnant women, both in terms of consumption and awareness of advice. 
This information together with some possible strategies outlined in the report may be considered useful for national public health authorities in their communication to consumers on this topic.