Eating a diet rich in oily fish, nuts and seeds cut the chances of dying from a heart attack by up to 10 per cent, researchers have found.
Fish such as salmon and mackerel contain high levels of omega-3 acids while walnuts, pecans, hazelnuts and vegetable oils are full of the plant-based equivalent.
Researchers from around the world joined together to form the Fatty acids and Outcomes Research Consortium (FORCE).
They pooled findings from a number of large studies measuring blood or tissue levels of omega-3 in relation to heart disease over time.
Eating a diet rich in oily fish like salmon and mackerel can aid your chances of recovery if you have a heart attack, according to a number of studies
Using 19 studies from 16 countries and including 45,637 participants, they found plant-based and seafood-based omega-3s were associated with about a 10 per cent lower risk of fatal heart attacks.
Of these, 7,973 people developed a first heart attack over time, including 2,781 deaths and 7,157 heart attacks which were not fatal.
In contrast, the fatty acids biomarkers were generally not associated with a risk of non-fatal heart attacks, suggesting a more specific mechanism for benefits of omega-3s related to death.
Study leader Soctor Liana Del Gobbo, a post-doctoral research fellow at Stanford University School of Medicine, said their findings represented the most comprehensive picture of how omega-3s may influence heart disease.
'Across these diverse studies, findings were also consistent by age, sex, race, presence or absence of diabetes, and use of aspirin or cholesterol-lowering medications,' he said.
Senior author Professor Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University, Boston, said: 'At a time when some but not other trials of fish oil supplementation have shown benefits, there is uncertainty about cardiovascular effects of omega-3s.
'Our results lend support to the importance of fish and omega-3 consumption as part of a healthy diet.'
Fish is the major food source of omega-3 fatty acids, including eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA).
Pecans, hazelnuts, walnuts and vegetable oils contain high levels of plant-based omega-3 which studies have linked to reducing someone's chances of dying from a cardiac episode
Experts say fatty fish - such as salmon, trout, anchovies, sardines, and herring - contain the highest amounts of omega-3 fatty acids, although all fish contain some levels.
In addition to omega-3 fatty acids, fish also provides specific proteins, vitamin D, selenium, and other minerals and elements.
Profesor Mozaffarian added: 'Most prior studies of dietary fats have relied on self-reported estimates of intake.
'This new global consortium provides an unprecedented opportunity to understand how blood biomarkers of many different fats and fatty acids relate to diverse health outcomes, and many additional investigations are in progress.'
The new study, published in the journal Internal Medicine, suggests that blood levels of seafood and plant-based omega-3 fatty acids are 'moderately associated' with a lower risk of dying from heart attacks.
Victoria Taylor, senior dietician at the British Heart Foundation, said eating oily fish is recommended as part of a balanced diet to help protect heart health.
'This study reinforces those recommendations and suggests there may also be a heart health benefit to omega-3 fats that come from vegetarian sources, such as flaxseed, rapeseed and soya oils, but more research would be needed to confirm these findings,' she said.
'Although eating a portion of oily fish a week has been recommended as part of a healthy balanced diet for some time, we know that there is still a way to go before people are meeting these recommendations.
'At the moment we just eat around a third of a portion a week on average.'