Fish oil and heart disease

Fish oil, with its omega-3 fats, is widely recommended as a supplement meant to reduce your risk of heart disease. It has become big business and many people wrongly believe that popping a fish oil capsule daily will protect their heart. It is true that we need omega-3s in our diet but the claim that fish oil can greatly reduce your risk of heart disease and all its complications is simply not supported by the science.

The most comprehensive review of evidence on the subject – a Cochrane review – found that taking omega-3 supplements (from any source) may ever so slightly reduce your risk of major cardiovascular events (heart attack or stroke) and dying from heart disease (Abdelhamid et al., 2020). However, these supplements do not reduce the risk of heart disease developing in the first place. The authors also noted that eating fish did not seem to have any effect.

Another set of studies found a concerning effect of fish oil supplements – they may actually increase the risk of atrial fibrillation (irregular heartbeat) by 25 per cent and if you take more than one gram daily, the risk may increase by up to 49 per cent (Gencer et al., 2021). Interestingly, plant-based omega-3s (ALA from flaxseed or flaxseed oil, chia seeds, hemp seed, walnuts or rapeseed oil) lower the risk (Abdelhamid et al., 2020).

Fish oil, just like any other “miracle cure” cannot make your heart healthy if your overall diet and lifestyle are lacking and thanks to the pollutants it contains, it might be even harmful. On the other hand, plant oils are healthy and may help to protect your heart, especially if you also have a wholesome vegan diet. Vegans and people whose diets are mainly plant-based have lower blood pressure and cholesterol levels than all other diet groups and a much lower risk of heart disease – 25-57 per cent (Bradbury et al., 2014; Le and Sabaté, 2014; Appleby and Key, 2016; Dinu et al., 2017; Benatar and Stewart, 2018; Kahleova et al., 2018; Korakas et al., 2018; Matsumoto et al., 2019).



Abdelhamid AS, Brown TJ, Brainard JS et al. 2020. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Systematic Reviews. 3(3):CD003177.

Appleby PN, Key TJ. 2016. The Long-Term Health of Vegetarians and Vegans. Proceedings of the Nutrition Society. 75 (3) 287-293.

Benatar JR and Stewart RAH. 2018. Cardiometabolic risk factors in vegans; A meta-analysis of observational studies. PLoS One. 13 (12) e0209086.

Bradbury KE, Crowe FL, Appleby PN et al. 2014. Serum concentrations of cholesterol, apolipoprotein A-I and apolipoprotein B in a total of 1694 meat-eaters, fish-eaters, vegetarians and vegans. European Journal of Clinical Nutrition. 68 (2) 178-183.

Dinu M, Abbate R, Gensini GF, Casini A, Sofi F. 2017. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Critical Reviews in Food Science and Nutrition. 57 (17) 3640-3649.

Gencer B, Djousse L, Al-Ramady OT et al. 2021. Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. Circulation. 144 (25) 1981-1990.

Kahleova H, Tura A, Hill M et al. 2018. A Plant-Based Dietary Intervention Improves Beta-Cell Function and Insulin Resistance in Overweight Adults: A 16-Week Randomized Clinical Trial. Nutrients. 10 (2) 189.

Korakas E, Dimitriadis G, Raptis A, Lambadiari V. 2018. Dietary Composition and Cardiovascular Risk: A Mediator or a Bystander? Nutrients. 10 (12) 1912.

Le LT, Sabaté J. 2014. Beyond meatless, the health effects of vegan diets: findings from the Adventist cohorts. Nutrients. 6 (6) 2131-2147.

Matsumoto S, Beeson WL, Shavlik DJ et al. 2019. Association between vegetarian diets and cardiovascular risk factors in non-Hispanic white participants of the Adventist Health Study-2. Journal of Nutrition Science. 8:e6.

How to change your diet

Going fish-free is not just a healthy choice, it’s also an ethical and sustainable one. If you’re used to meals based around fish and other animal products, the idea of a plant-based diet may be daunting but we’re here to help make it super easy!

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All about fish

Find all the above and more in Viva!’s resources on fish:

Delve deep into the science beyond health claims and fish in The Fish Report.

Find out more about fish, fish oil and omega-3s in the Fish-free for Life guide.

Or see the summary in this handy Fishing for Facts factsheet.

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