Fish has long enjoyed a reputation as one of the healthiest foods we can eat. From the Mediterranean diet to traditional Japanese eating patterns, it frequently appears in populations associated with good cardiovascular health and longevity. But does eating more fish actually help us live longer? And perhaps more interestingly, is there still a benefit if we're already eating a reasonable amount?

A new systematic review and meta-analysis published in the European Journal of Clinical Nutrition has explored this question by examining fish consumption and mortality in Japanese populations. The findings suggest that people who eat more fish may have a modest advantage when it comes to living longer, particularly in relation to cardiovascular disease.

However, as with so much nutritional research, there's an important difference between identifying an association and establishing what is actually causing it.

What Did the Researchers Find?

The researchers brought together observational evidence examining the relationship between fish consumption and mortality in Japan. This is an interesting population to study because fish has traditionally been a regular part of the Japanese diet, rather than an occasional addition to the menu.

When they compared people with the highest fish consumption against those with the lowest, they found that the higher-intake group had a 15% lower relative hazard of cardiovascular death and a 6% lower relative hazard of death from any cause.

These are meaningful findings, particularly when we consider how common cardiovascular disease is. But they need to be interpreted carefully. A 15% lower relative hazard doesn't mean that 15 out of every 100 people avoided cardiovascular death because they ate fish. It describes a relative difference between groups over the periods studied.

And because the underlying studies were observational, we cannot conclude that eating fish was directly responsible for those differences. People who eat more fish may also differ in other aspects of their diets, lifestyles and overall health.

Nevertheless, the findings add another interesting piece to the wider picture of fish consumption and cardiovascular health.

What Makes Fish So Interesting for Heart Health?

Much of the scientific interest in fish centres on two particular omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

These long-chain omega-3 fats are especially abundant in oily fish such as salmon, sardines, mackerel and herring. They become incorporated into cell membranes and participate in several physiological processes relevant to cardiovascular function.

One of their best-established effects involves blood triglycerides. EPA and DHA can reduce the liver's production and release of triglyceride-rich lipoproteins, helping to lower circulating triglyceride concentrations. This effect is particularly apparent at the higher doses used in clinical treatment.

Omega-3 fatty acids also influence inflammatory signalling and the production of various lipid-derived compounds involved in vascular function. These mechanisms are biologically interesting, although they don't automatically mean that eating more fish will prevent a heart attack or extend somebody's lifespan.

There's also an important distinction between different types of fish. Oily fish provides considerably more EPA and DHA than most white fish, although both can contribute valuable protein and other nutrients.

Could the Benefits Be About What Fish Replaces?

This is one of the most overlooked questions in nutrition research.

When somebody eats more of one food, they're often eating less of something else. So the potential benefit of fish might not be entirely about the fish itself, but also about what it replaces.

For example, replacing some processed meat or foods high in saturated fat with fish may improve the overall nutritional composition of the diet. Fish provides high-quality protein, while oily varieties supply unsaturated fats that can form part of a heart-healthy eating pattern.

But replacing beans, lentils or other nutritious plant proteins with additional fish may not produce the same benefits.

This is why it's difficult to isolate the effect of a single food from the wider dietary pattern. The health implications of eating fish depend partly on how it's prepared, what accompanies it and what would otherwise have been eaten.

Does Eating Fish Offer the Same Benefits as Taking Omega-3 Supplements?

Not necessarily, and this is an important distinction.

It's tempting to assume that if fish consumption is associated with better cardiovascular outcomes, taking a fish oil capsule should produce exactly the same effect. Unfortunately, the evidence isn't quite that straightforward.

Clinical trials of omega-3 supplements have produced mixed results for preventing cardiovascular events, particularly in generally healthy populations. Certain prescription omega-3 treatments have demonstrated benefits in specific higher-risk groups, but those findings cannot simply be applied to ordinary over-the-counter fish oil supplements.

Fish is also more than a delivery system for EPA and DHA. It provides protein and a range of micronutrients, and eating it can influence the overall composition of the diet.

In other words, we shouldn't automatically assume that isolating one nutrient will reproduce all the associations observed when people eat the whole food.

So, Should We All Be Eating More Fish?

The Japanese findings are particularly interesting because they suggest that differences in fish consumption may matter even within a population where fish is already a familiar part of the diet.

However, the study doesn't establish that continually increasing fish intake produces progressively greater benefits. Nor does it tell us that everyone should be eating fish every day.

For most people who choose to eat fish, a sensible starting point remains the established UK recommendation of two portions per week, including one portion of oily fish, while observing specific advice on fish choices and consumption limits where relevant.

And for those who don't eat fish, there are still plenty of ways to build a nutritious dietary pattern around vegetables, fruit, wholegrains, legumes, nuts and unsaturated fats.

Perhaps the most useful message from this research is that fish can be a valuable component of a healthy diet, but it isn't a magic ingredient for longevity.

Ultimately, living longer and ageing well are influenced by the overall pattern of what we eat, alongside many other biological, environmental and lifestyle factors. Fish may be one helpful piece of that puzzle, rather than the answer on its own.

References

Yokoi, K. et al. (2026) Systematic review and meta-analysis of fish consumption and mortality in Japanese populations. European Journal of Clinical Nutrition. https://doi.org/10.1038/s41430-026-01832-0