Consuming foods high in omega-3 fatty acids such as salmon, trout, walnuts and flaxseed oil may lower the risk of fatal heart disease, a new global study has claimed.
By pooling findings from diverse large studies that had measured blood or tissue levels of omega-3 fatty acids, researchers evaluated relationships with heart disease events over time.
They found that blood levels of seafood and plant-based omega-3 fatty acids are moderately associated with a lower risk of dying from heart attacks.
“These new results, including many studies which previously had not reported their findings, provide the most comprehensive picture to-date of how omega-3s may influence heart disease,” said Liana C Del Gobbo from Stanford University in the US.
“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,” said Dariush Mozaffarian from Tufts University in the US.
“Our results lend support to the importance of fish and omega-3 consumption as part of a healthy diet,” he added.
Fish is the major food source of omega-3 fatty acids, including eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), researchers said.
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 provide specific proteins, vitamin D, selenium, and other minerals and elements, researchers said.
Alpha-linolenic acid (ALA) is the plant-based omega-3 fatty acid found in walnuts, flaxseed oil, and canola oil and some other seed and nuts and their oils, they said.
A total of 19 studies were involved from 16 countries and including 45,637 participants. Of these, 7,973 people developed a first heart attack over time, including 2,781 deaths and 7,157 nonfatal heart attacks.
Overall, both plant-based and seafood-based omega-3s were associated with about a 10 per cent lower risk of fatal heart attacks, researchers said.
In contrast, these fatty acids biomarkers were generally not associated with a risk of nonfatal heart attacks, suggesting a more specific mechanism for benefits of omega-3s related to death, they said.
The findings were published in JAMA Internal Medicine.