Fish oil supplements don’t improve heart health, and they might even hurt you

Omega-3 capsules have long been touted to benefit our cardiovascular health. Science says not.

Omega-3 capsules have long been touted to benefit our cardiovascular health. Science says not. Photo: Getty

Fish oil supplements are pretty things to look at, like glistening golden jewels. Beyond that, there is growing opinion that they probably don’t make life better, certainly not your heart health.

Nor do they offer protection against cancer.

However, as a benefit for your heart, fish oil (specifically omega-3) from eating oily fish two to three times a week is a different matter entirely.

If a piece of salmon is a little too hard on your pocket, try canned sardines or anchovies. See the Heart Foundation’s advice here.

But wait … what?

Haven’t we been told for years that fish oil supplements are good for the brain and heart? Haven’t we?

Yes, we have: mostly by the people selling them.

But the scientific evidence has been mixed. And recent studies have become increasingly skeptical.

The shift began about five years ago with a number of large-scale analyses of randomised controlled clinical trials that found omega 3 fatty acid supplements didn’t meaningfully prevent premature death or impact heart health.

None of this is conclusive yet. It’s more than an argument is going on among scientists.

If you find this confusing, your doctors do as well.

What are omega 3 fatty acids?

Small amounts of omega-3 fats are essential for good health: they are responsible for numerous cellular functions, including cell membrane fluidity, and structural maintenance.

They also regulate the nervous system, blood pressure, hematic clotting, glucose tolerance, and inflammatory processes, which may be useful in all inflammatory conditions.

Omega-3 fats can be found in the food we eat.

The main types of omega 3 fatty acids are:

  • Alphalinolenic acid (ALA),normally found in fats from plant foods, such as nuts and seeds. Walnuts and rapeseed are rich sources.
  • Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), collectively called long chain omega 3 fats, are naturally found in fatty fish, such as salmon and fish oils including cod liver oil.

 The doctor’s dilemma

In 2021, Dr Alyson Kelley-Hedgepeth, a cardiologist, wrote a piece for Harvard Medical School’s publishing arm. She laid out the problem:

“My patients commonly ask me whether they should try one supplement or another … The results of studies looking at omega-3 supplements have been inconsistent, and have left both physicians and patients wondering what to do.”

Her piece is worth reading, because she discusses two major studies that give conflicting advice.

While she has largely advised that omega-3 be obtained through diet, she has continued to prescribe a particular brand of fish oils sold under the brand name Vascepa that is high in eicosapentaenoic acid (EPA).

She made this decision based on results of what’s known as the REDUCE-IT trial published in 2019.

The US Federal Drug Administration in 2020 approved the use of Vascepa to reduce the risk of cardiovascular events in certain patients with, or at high risk of, CVD.

But then the 2020 STRENGTH trial was published. This found that doses of the omega-3 fatty acids EPA and DHA were no more effective than a corn syrup placebo.

Worse: “An abnormal heart rhythm, known as atrial fibrillation, occurred more frequently in (study) participants taking the medication, much like other previous studies evaluating similar medications.”

The doctor’s decision

Dr Kelley-HedgepethI continues to recommend “a pure EPA supplement, or one that contains more EPA than DHA”.

But she also advises her patients to “eat a heart-healthy diet, get regular exercise, and pursue other lifestyle changes that have proven benefits for cardiovascular health.”

In the meantime, she writes, “my colleagues and I wait for more definitive data on the utility of omega-3 fish oil, and who might benefit the most”.

A month later

A month after Dr Kelley-Hedgepeth published her piece, something of a bombshell went off.

The European Society of Cardiology published a new analysis which found that omega-3 fatty acid supplements were associated with an increased likelihood of developing atrial fibrillation (AFib) in people with a high risk of, or existing, heart disease. (Read: high triglyceride levels.)

Previous clinical trials had suggested this might be the case.

Study author Dr Salvatore Carbone, of Virginia Commonwealth University said:

“Our study suggests that fish oil supplements are associated with a significantly greater risk of atrial fibrillation in patients at elevated cardiovascular risk.”

He said the risk for atrial fibrillation should be considered when such agents are prescribed or purchased over the counter. This was especially important “in individuals susceptible to developing the heart rhythm disorder”.

Most pills are of poor quality anyway

In a new study, University of Texas researchers looked at the amount of active compounds EPA and DHA in 255 fish oil supplements.

Only 24 of the supplements (around one in ten) contained a daily dose of 2 grams or more EPA+DHA. This is the level recommended for lowering cholesterol.

The researchers suggest that stricter regulation of the supplements industry “could help address these shonky practices”.

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