Are Omega-3 Supplements Just Fishy Business?

Based on the hype, you’d be forgiven for believing that fish-oils known as omega-3s are a panacea, but what does the science actually say?

Rob Lefort

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In Fitness And In Health

6 min readAug 7, 2022

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Before the 1970s, hardly anyone had ever heard of omega-3 fatty acids. Fast forward fifty years and the omega-3 supplementation business has grown into a multibillion dollar industry, with over 100,000 tons of fish oil get consumed every year.

For years, omega-3 fatty acids, taken in capsule form as supplements, have been considered as the Holy Grail of health and regarded as having near-miraculous effects on weight loss, cardio-vascular protection and cognitive function. With over ten percent of Americans taking a capsule of fish oil daily, omega-3s are one of the most profitable supplements in the world.

How the heck did that happen?

What exactly are Omega-3s?

The three main omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

EPA and DHA are fish oils found in cold-water fish such as salmon, mackerel, halibut, sardines, tuna, and herring. ALA is found in flaxseeds, flaxseed oil, canola (rapeseed) oil, soybeans, soybean oil, pumpkin seeds, pumpkin seed oil, purslane, perilla seed oil, walnuts, and walnut oil.

ALA is an essential fatty acid, meaning that your body can’t make it, so you must get it from the foods you consume. Your body can convert some ALA into EPA and then to DHA, but only in tiny amounts. Therefore, getting EPA and DHA from foods (and dietary supplements) is the only practical way to increase levels of these omega-3 fatty acids in your body.

An Eskimo fish tale

The common myth about the curative virtues of fish-oils originated in the early 1970s, when a team of Danish researchers stationed in Greenland found that a local Inuit community had remarkably low levels of diabetes and heart disease. The absence of coronary artery disease is most unusual in a native population whose diet is mainly meat-based, with very little intake of fruits and vegetables, violating all principles of heart-healthy nutrition. This paradox was attributed to all the seal and whale blubber — in other words, fish-oils— and the rest is history. At the time, it seemed a very attractive proposition. The problem is, it turned out not to be true.

The fact is that researchers accepted at face value this notion that coronary atherosclerosis is almost unknown among the Eskimo, a concept that has since been disproven. Going back over a thousand years, we have frozen Eskimo mummies with atherosclerosis. The totality of evidence from actual clinical investigations, autopsies, and imaging techniques is that they have the same plague of coronary artery disease that non Eskimo populations have, and actually have twice the fatal stroke rate and don’t live long — which is hardly surprising considering the harshness of their environment.

Ironically, Eskimos have such poor health that the Westernization of their diets actually lowered their rates of ischemic heart disease. As Dr. Michael Greger from Nutritionfacts.org puts it:

“You know your diet is bad when the arrival of Twinkies improves your health” — Dr. M. Greger

The science on fatty-acids is getting weird

Thanks to controversial recommendations from the American Heart Association — that individuals at high risk for heart disease ask their physicians about fish oil supplementation — the market for fish-oil supplements continues to grow at an astronomical rate.

The growth of the science supporting fish oil’s properties has been far less impressive.

The early papers that sparked the initial enthusiasm were merely observational, meaning that they could establish only correlation, not causation. When the randomized control trials — the gold standard for research studies— eventually trickled in, the results were mixed at best.

Although no study is likely on its own to prove causality, randomization reduces bias and provides a rigorous tool to examine cause-effect relationships between an intervention and outcome. Randomized control trials are hard to run with food studies as participants know what’s on their plate and you can’t easily replace a serving of sardines with a placebo version. But with supplements and pills, that’s not an issue.

Thousands of studies after the observational Eskimo findings, things haven’t gotten all that much clearer: We are still nowhere close to a firm grasp of what fish-oils can do and what it cannot.

Most researchers acknowledge fish oil has some modest benefits in certain cases. Omega-3 has been shown to lower levels of a LDL cholesterol associated with heart failure. But findings are a far cry from the game-changing promise of the early studies. Scientists still debate which omega-3 DHA or EPA compound provides the most benefits. Maybe the benefit comes from pairing the two. Maybe neither does anything unless it’s consumed with other parts of the actual fish. Or perhaps the reason trial participants were healthier had more to do with the fact that if you’re eating fish, you’re probably not also eating a beef burger or fried chicken. Today, we are none the wiser.

What to make of it

It is likely that a definite answer on the effects of omega-3 fatty acids on the body will never be clearly established, as nutrition related studies are extremely difficult to carry out. It is nearly impossible to isolate reactions from a single piece of the smorgasbord that is our daily food intake.

One can wonder why researchers have continued to parrot the fish-oil myth? Publications still referring to the original Danish study as proof that Eskimos have a low prevalence of heart disease represent either misinterpretation of the original findings or an example of confirmation bias — which is when people cherry pick or slant information to confirm their preconceived idea.

Nutritionists should fall back on common sense and recommend eating a more varied and balanced diet consisting mainly of home cooked foods and wholegrain products. The key to staying as healthy as possible is paying attention to eating a diverse diet — omega-3 included — and we should consider that in most cases food supplements are unnecessary and should be regarded as expensive placebos.

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