Fish and seafood are widely recommended as part of a healthy diet. They provide important nutrients, including omega-3 fatty acids, iodine, vitamin D and high-quality protein. But some species can also contain traces of mercury, which raises questions about how much fish people should eat.
A recent survey by the European Food Safety Authority (EFSA) examined how often people in Europe consume fish and seafood that may contain mercury and whether they are aware of national dietary advice.
The research was requested by the European Commission as part of ongoing discussions about mercury limits in fish and seafood sold in the European Union.
How often Europeans eat fish and seafood
EFSA carried out an EU-wide survey in April–May 2023 across all 27 EU countries, Iceland and Norway. A second survey was later conducted in 15 countries, including 10 that had updated their dietary advice and five that had not, allowing researchers to compare awareness and behaviour.
According to the survey:
- 60% of respondents said they eat fish or seafood.
- Among those consumers, about one-third eat fish species with higher mercury levels three or more times per week.
- This included 34% of adolescents and adults and 33% of pregnant women.
However, EFSA notes that the results should be interpreted cautiously because of uncertainties about how representative the surveys were.
Which fish contain more mercury?
Mercury tends to accumulate in large predatory fish, which feed on smaller fish over long lifespans.
Species more likely to contain higher levels include:
- shark
- swordfish
- large tuna species such as bigeye or bluefin
The form of mercury most relevant to food safety is methylmercury, which can affect the nervous system, particularly in developing foetuses and young children.
How much fish is recommended?
Most national health authorities in Europe advise regular fish consumption, but with some limits depending on the type of fish.
Typical recommendations include:
- 1–2 portions per week of fish species with higher mercury limits (around 1.0 mg/kg).
- 3–4 portions per week of fish species with lower mercury levels (0.5 mg/kg or 0.3 mg/kg).
For pregnant women, national guidance often recommends replacing large predatory fish with smaller species that contain less mercury.
These recommendations aim to balance the health benefits of fish consumption with the potential risks from mercury exposure.
Health benefits of fish
EFSA notes that eating fish and seafood provides several health benefits.
These include:
- support for brain and immune system development in infants, when consumed during pregnancy
- reduced risk of cardiovascular disease in adults
- intake of important nutrients such as omega-3 fatty acids and iodine
At the same time, limiting consumption of certain species helps reduce exposure to methylmercury.
Are consumers aware of the advice?
The survey also looked at whether people know about national recommendations.
According to EFSA social scientist Angela Bearth, awareness does not always translate into behaviour.
“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.”
The research also showed that:
- about half of respondents knew about the health benefits of fish,
- but only around one in ten were aware of health risks.
Mercury was the most widely recognised contaminant linked to seafood.
Why the findings matter
EFSA says the survey highlights differences between countries and population groups in both seafood consumption and awareness of dietary advice.
The results may help public health authorities improve how they communicate guidance on fish consumption, especially for pregnant women and other groups who may be more sensitive to mercury exposure.
For most people, experts agree that moderate fish consumption remains an important part of a balanced diet — as long as the types and amounts of fish are chosen carefully.
