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New research finds that fish oil supplements may increase heart disease and stroke risks in healthy people. Pranithan Chorruangsak/Getty Images
  • A study has found that fish oil supplements are linked to increased first-time CVD risk.
  • However, they were beneficial to those who already have CVD.
  • It appears that the risks of fish oil supplements outweigh the benefits in healthy people.
  • Experts advise against using fish oil supplements if you are currently healthy.
  • Eating a heart-healthy diet containing omega-3 sources like fatty fish may be best.

Fish oil derived from fatty fish like salmon, mackerel, and trout is often recommended for its anti-inflammatory effects, especially in people with cardiovascular disease (CVD), high blood pressure, abnormal lipids, and rheumatoid arthritis.

Fatty fish are a great source of two omega-3 fatty acids that the human body needs but cannot make for itself: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

However, while it might seem like a good idea for healthy people to also supplement with fish oil to help prevent disease, the results of a large, long-term study published on May 21, 2024, in the journal BMJ Medicine, indicate that this may not be the case.

The researchers found that using fish oil on a regular basis might actually increase the risk for healthy people to go on and develop first-time heart disease and stroke.

Regular use did, however, help slow the progression of existing CVD. It also helped reduce their risk of death.

The researchers included 415,737 people from the UK Biobank study.

Over half (55%) of the participants were women, and their ages ranged from 40 to 69.

The information collected about the individuals included their use of fish oil supplements and their dietary intake of oily and non-oily fish.

People’s health was tracked until either their death or the end of the study in March 2021.

About a third of people said they used fish oil supplements on a regular basis, with the majority of them being older, white, and female.

Among those who had no known CVD at the start of the study, regular usage of fish oil supplements was linked with a 13% increased risk of developing atrial fibrillation and a 5% greater risk of having a stroke.

However, those regular users of fish oil who had CVD at the beginning of the study saw a 15% lower risk of going from atrial fibrillation to a heart attack and a 9% lower risk of progressing from heart failure to death.

Dr. Michael O. McKinney, primary physician at Healthy Outlook in Jacksonville, Florida, explained that the omega-3 fatty acids found in fish oil supplements have been widely studied and found to have both anti-inflammatory and lipid-lowering effects.

“In individuals with established CVD, these properties can stabilize atherosclerotic plaques, lower levels of serum triglycerides, and improve endothelial function, thereby reducing cardiovascular adverse events,” he said.

McKinney noted, however, that the situation is not quite so straightforward when people are in good health.

“Their potential merits at high doses of omega-3s could enhance the risk of bleeding by their anticoagulant effects outweighing benefits in individuals lacking significant cardiovascular disease risks,” he stated.

Taking fish oil supplements when you are healthy could also result in fatty acid imbalances, perhaps inadvertently increasing a person’s risk for heart disease, according to McKinney.

Dr. Sarah Bonza, a board certified family physician and founder of Bonza Health in Columbus, Ohio, said another factor to consider is that some research has suggested that fish oil might increase healthy people’s risk for atrial fibrillation, a heart rhythm disturbance linked with greater stroke risk.

“However, for people with preexisting poor cardiovascular health, omega-3s indeed have anti-inflammatory and plaque-stabilizing effects,” she added, “which help in slowing the progression of cardiovascular disease and in reducing the chances of death from heart-related events.

“So, these advantages may be more than the hazards in patients with weakened cardiovascular systems,” said Bonza.

“If you are healthy and you seek to use fish oil capsules for preventing heart disease, it might be better to think over your decision,” said Bonza.

She further stated that the American Heart Association does not advocate taking omega-3 supplements if you are at low risk for CVD because the effects are “far more enhanced” in those with the disease.

Instead, Bonza suggests eating a heart-healthy diet with plenty of natural omega-3 sources, such as fish.

In her opinion, this will be more beneficial to your health.

“On the other hand, personal health condition factors differ, so it is important to talk to a healthcare provider first before choosing to modify supplement consumption​,” she added. “Talk to your doctor first to be safe.”

Bonza said she would recommend supplementing with flaxseed oil or chia seeds instead of fish oil due to their high alpha-linolenic acid (ALA) content. This is a plant-based omega-3 fatty acid, she explained.

She suggests augmenting your diet with this type of fatty acid because it might have anti-inflammatory properties that can benefit your cardiovascular health, but it is not associated with the risk of atrial fibrillation.

“Also, the diet that contains omega-3s in the form of nuts, soy products, and fortified food will provide the same benefits without high-dose supplements,” she added.

McKinney additionally suggests supplementing with other heart-supporting supplements, such as Coenzyme Q10 (CoQ10), and fiber supplements, such as psyllium husk.

“In addition, everyone has to consult their healthcare providers so that individual patients adjust their choices of supplementation corresponding to their health problems and peculiarities,” he concluded.

A new study has found that fish oil supplementation was associated with an increased risk of developing heart disease and stroke in healthy people.

However, people with existing CVD experienced protective effects against further progression of their disease.

This was an observational study. It does not prove causation.

Experts say the difference in how fish oil affects people’s risk might be due to the fact that in healthy people, the risks associated with fish oil supplementation — such as bleeding, fatty acid imbalance, or atrial fibrillation — might outweigh any potential benefits.

For healthy people, it may be best to get omega-3 fatty acids from foods like fatty fish.

Flaxseed oil, chia seeds, foods fortified with omega-3 fatty acids, CoQ10, and psyllium husk may be safer supplements for cardiovascular health.