VoltraOmega-3 and fish oil: do you need a supplement?
If you're healthy, probably not. The American Heart Association doesn't recommend omega-3 supplements for people who aren't at high risk of heart disease [1][2], and in a trial of 25,871 people, 1 g a day for about five years didn't lower major heart events or cancer [3]. Saudi Arabia's health ministry, citing the same association, advises eating fish, especially oily fish such as salmon and mackerel, at least twice a week [5].
After a recent heart attack, taking omega-3 supplements is reasonable, in the association's words [2]; that's a decision for your doctor.
What the big studies found
- VITAL, 25,871 people: over a median of 5.3 years, 1 g a day didn't lower major cardiovascular events or cancer compared with a placebo [3].
- A Cochrane review of 86 trials: little or no effect on deaths from any cause, and a slight reduction in heart-disease deaths and events and in blood triglycerides, on moderate- and low-certainty evidence [4].
- The evidence of protection is stronger for people who already have coronary heart disease than for healthy people [1].
How much
There's no official daily amount of EPA and DHA in the US [1]. In Europe, dietary recommendations are 250 to 500 mg of EPA and DHA a day [6]. Supplements of up to 5 g a day of EPA and DHA combined raise no safety concerns for adults in Europe [6], and the US FDA considers up to 5 g a day safe as recommended [1].
The heart-rhythm risk at higher doses
Two large trials found that 4 g a day for several years slightly increased the risk of atrial fibrillation, an irregular heartbeat, in people with or at high risk of heart disease [1]. A meta-analysis found omega-3 supplements raised the risk of atrial fibrillation, more so in trials using more than 1 g a day [7], and the MSD Manual warns that very large doses may raise it too [8].
Who should ask first
- People on warfarin: fish oil may add to its blood-thinning effect, so ask your doctor first [8].
- Pregnancy and breastfeeding: advice differs. The MSD Manual's Arabic edition says pregnant and breastfeeding women shouldn't take omega-3 supplements made from fish [8], while the NIH fact sheet lists recommendations for extra DHA in pregnancy [1]. Ask your doctor.
In Voltra
Log fish meals and fish-oil capsules on the Eat tab, or ask the Coach to log them; fish oil carries a few calories, and Voltra counts them.
Frequently asked
Should I take omega-3 supplements?
Not if you're healthy and not at high risk of heart disease: the American Heart Association doesn't recommend them for you, and a large trial of 1 g a day found no drop in heart events. Eat fish twice a week.
How much omega-3 is too much?
Up to 5 g a day of EPA and DHA from supplements raises no safety concerns for adults, but doses above 1 g a day have been linked with a higher risk of atrial fibrillation.
Is it better to eat fish or take fish oil?
Saudi Arabia's health ministry advises eating fish, especially oily fish, at least twice a week.
Can I take fish oil with blood thinners?
Ask your doctor first: fish oil may add to warfarin's blood-thinning effect.
Sources
- NIH Office of Dietary Supplements (2025). Omega-3 fatty acids: fact sheet for health professionals (updated 22 August 2025). Recommended intakes, cardiovascular disease, safety.
- Siscovick DS, Barringer TA, Fretts AM, et al. (2017). Omega-3 polyunsaturated fatty acid (fish oil) supplementation and the prevention of clinical cardiovascular disease: a science advisory from the American Heart Association. Circulation 135(15):e867–e884. Primary prevention; clinical implications; conclusions.
- Manson JE, Cook NR, Lee IM, et al. (2019). Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med 380(1):23–32. Abstract. 25,871 people, 1 g a day.
- Abdelhamid AS, Brown TJ, Brainard JS, et al. (2020). Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 3:CD003177. Abstract. 86 trials, mixing primary and secondary prevention.
- وزارة الصحة، المملكة العربية السعودية. الأسماك. In Arabic. Recommended amount.
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2012). Scientific Opinion on the Tolerable Upper Intake Level of EPA, DHA and DPA. EFSA Journal 10(7):2815. Abstract.
- Gencer B, Djousse L, Al-Ramady OT, et al. (2021). Effect of long-term marine ω-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. Abstract.
- دليل MSD الإرشادي، إصدار المستخدم. زيت السمك. In Arabic. Side effects and interactions.
Sources checked on 30 September 2026.
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