Fish-oil supplements: another weapon against high blood pressure

The Bottom Line

  • The omega-3 fatty acids found in fish like salmon and mackerel are known to promote heart health.
  • Taking fish-oil supplements is an alternative to eating fish.
  • Fish-oil supplements can help reduce systolic and diastolic blood pressure in people with high blood pressure.

Does the thought of a seared tuna steak or a meal of delicately poached salmon make your mouth water? If so go ahead and indulge – it isn’t often that something we love to eat may actually be good for us!

We’ve known for some time about the benefits of consuming “fatty” fish like salmon, mackerel, tuna, trout, herring and sardines. Their good-for-you omega-3 fatty acids are widely believed to help prevent heart disease (1). Consequently, health advocates around the world recommend two to three servings of fatty fish a week (2).

But what if you don’t want to eat fish that often or what if you don’t like fish at all? This is where supplements come in: fish oil capsules are readily available and easy to take (though not nearly as tasty as that salmon filet). A recent systemic review of 17 randomized controlled trials was conducted to find out if they actually do help (3). Specifically, the researchers sought to discover whether fish-oil supplements helped to lower blood pressure, a major factor in reducing the risk of heart attacks and strokes.

The studies involved more than 1,500 adults with an average age of 50, approximately half with high blood pressure (140/85 mmHg or greater) and the rest whose blood pressure was normal. The dosages varied but most of the participants took fish-oil capsules a few times a day and all took the supplements for a minimum of eight weeks. Among those with high blood pressure, some were newly diagnosed and not taking any blood pressure lowering medications; others had been taking medication but stopped prior to participating in the study; and some continued to take their usual medications.

What the research tells us

The results showed that among those with high blood pressure, taking fish oil supplements lowered both systolic and diastolic blood pressure by a small amount (average decreases of 2.56 mmHg and 1.47 mmHg for systolic and diastolic blood pressure respectively). There was no change in blood pressure among those with normal blood pressure.

Fish-oil supplements are not recommended as an alternate therapy for people who have been prescribed blood pressure-lowering medications. However, eating fatty fish or taking fish oil supplements may be an additional strategy for helping to lower blood pressure and maintaining heart health.

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Author Details


  1. Marik PE, Varon J. Omega-3 dietary supplements and the risk of cardiovascular events: a systematic review. Clin Cardio. 2009; 32:365-372.
  2. Kris-Etherton PM, Harris WS, Appel LJ. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002; 106:2747-2757.
  3. Campbell F, Dickinson HO, Critchley JA, et al. A systematic review of fish-oil supplements for the prevention and treatment of hypertension. Eur J Prev Cardiol. 2013; 20:107-120.

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