Omega-3 fatty acids

Does plant omega-3 (ALA) protect the heart?

Updated 9 Nov 2026

Short answer

Possibly a little. A 2020 Cochrane review of 5 trials with 19,327 people found that more ALA may slightly reduce cardiovascular events and probably slightly reduces arrhythmia. It made little or no difference to deaths.[1] Studies that observe people link more ALA in the diet with about a 10% lower risk of cardiovascular disease.[2]

What trials found

The 2020 Cochrane review included only randomized trials that lasted at least 12 months.[1] For ALA it found 5 trials with 19,327 people. Compared with less ALA, more ALA:[1]

  • made little or no difference to deaths from any cause (risk ratio 1.01, moderate certainty)[1]
  • made little or no difference to deaths from heart and blood vessel disease (risk ratio 0.96)[1]
  • may slightly reduce cardiovascular events (risk ratio 0.95, low certainty), about 1 event fewer for every 500 people[1]
  • probably slightly reduces arrhythmia, an irregular heartbeat (risk ratio 0.73, 2 trials with 4,912 people), about 1 case fewer for every 91 people[1]

The effect on stroke was unclear.[1]

A 2022 review describes three trials of diets high in ALA: AlphaOmega, PREDIMED and the Lyon Diet Heart Study. All three showed benefits on heart outcomes, but AlphaOmega, the one designed to test ALA itself, showed only a trend.[2]

What observational studies found

A 2012 review of 27 studies with 251,049 people compared the top third of ALA intake or blood level with the bottom third. The top third had a 14% lower risk of cardiovascular disease.[3] Results differed a lot between studies. The link was clear in studies of ALA in the diet, but not statistically significant in studies that measured ALA in blood or fat tissue.[3] The authors asked for large randomized trials to test ALA.[3]

A 2022 review summed up the observational studies as about 10% lower risk of all cardiovascular disease and 20% lower risk of fatal coronary heart disease with more ALA.[2]

Why it may work

In trials described by the 2022 review, ALA lowered total and LDL cholesterol, triglycerides and blood pressure. Some studies also found less inflammation.[2] The Cochrane review, which counted only trials of at least 12 months, found little or no effect of ALA on blood fats and blood pressure.[1]

The body turns less than 15% of ALA into EPA and DHA.[4] Extra ALA raises EPA in the blood but changes DHA very little.[5] To raise EPA and DHA in practice, they have to come from food or from supplements such as fish oil.[4]

Foods used in the research

The main food sources of ALA in this research are walnuts and flaxseed.[2] One tablespoon of flaxseed oil has 7.26 g of ALA. The US adequate intake for men is 1.6 g a day.[4]

One trial gave 110 people with peripheral artery disease foods with 30 g of milled flaxseed a day, or placebo, for 6 months. Systolic blood pressure was about 10 mmHg lower and diastolic about 7 mmHg lower with flaxseed.[6] Flaxseed also contains lignans and fiber, so this trial does not show which part caused the effect.[6]

What is still unknown

The Cochrane review found only 5 trials of ALA, and the certainty of its results was low to moderate.[1] Most research on omega-3 and cardiovascular health tested EPA and DHA, not ALA.[4]

Sources (6)

  1. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, et al. Cochrane Database Syst Rev, 2020. PMID 32114706
  2. Impact of α-Linolenic Acid, the Vegetable ω-3 Fatty Acid, on Cardiovascular Disease and Cognition. Sala-Vila A, Fleming J, Kris-Etherton P, Ros E Adv Nutr, 2022. PMID 35170723
  3. α-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis. Pan A, Chen M, Chowdhury R, Wu JH, Sun Q, Campos H, et al. Am J Clin Nutr, 2012. PMID 23076616
  4. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  5. alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Brenna JT, Salem N Jr, Sinclair AJ, Cunnane SC Prostaglandins Leukot Essent Fatty Acids, 2009. PMID 19269799
  6. Potent antihypertensive action of dietary flaxseed in hypertensive patients. Rodriguez-Leyva D, Weighell W, Edel AL, LaVallee R, Dibrov E, Pinneker R, et al. Hypertension, 2013. PMID 24126178

More about omega-3 fatty acids

What are omega-3 fatty acids?What is the difference between ALA, EPA and DHA?What are omega-3 fatty acids used for?Which foods are high in omega-3?Are omega-3 supplements safe?Does omega-3 lower blood pressure?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.