Heart health may be improved by a daily dose of fatty acids found in certain fish, a new study suggests.
Researchers say a helping of fatty fish like salmon, tuna, sardines and trout - or oysters - could do the heart good.
Scientists set out to find the exact amount of omega-3 fatty acids needed to lower blood pressure in a new study published in the Journal of the American Heart Association.
It found people had a 'modest' blood pressure reduction from consuming three grams of fatty acids daily.
A note before you hit the shops - the study says that's equivalent to about a 114 to 142g serving of Atlantic salmon.
Fish oil supplements may contain about 1000mg of omega-3s per pill, but doses can vary.
For adults with high blood pressure or high blood lipids, their findings showed having more than three grams of omega-3 fatty acids every day may boost the blood pressure-lowering benefit even further.
The study looked at 71 clinical trials that examined the relationship between blood pressure and these fatty acids in adults with or without high blood pressure or cholesterol disorders.
"Our study supports the [US Food and Drug Administration] guidance that EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease by lowering high blood pressure, especially among people already diagnosed with hypertension," said study author Xinzhi Li, MD, PhD.
He cautioned: "However, while our study may add a layer of credible evidence, it does not meet the threshold to make an authorized health claim for omega-3 fatty acids in compliance with FDA regulations."
Researchers analysed 71 clinical trials worldwide from 1987 to 2020 that amounted to 5,000 participants combined.
"Most of the studies reported on fish oil supplements rather than on EPA and DHA omega-3's consumed in food, which suggests supplements may be an alternative for those who cannot eat fatty fish such as salmon regularly," Li said.
He added that algae supplements with EPA and DHA fatty acids are an option for those who don't consume animal products.
The study notes that limitations of the review include differences in how blood pressure was measured, and whether the studies examined omega-3 intake from supplements or diet, which may affect the strength of the conclusions.
The NHS says oily fish - such as salmon and sardines - are particularly high in long-chain omega-3 fatty acids, which can help to keep your heart healthy.
It says: "A healthy, balanced diet should include at least two portions of fish a week, including one of oily fish. Most of us aren't eating this much. A portion is around 140g (4.9oz),"
The advice is similar across the pond - the American Heart Association recommends eating two servings (3-4 ounces cooked) of fish per week (particularly fatty fish such as salmon) as part of a heart-healthy diet.
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