What Are The Benefits Of Omega-3s? Here’s The Latest Science

The possible benefits of omega-3 fatty acids have been studied for several health conditions, ranging from those affecting the brain like ADHD and Alzheimer’s, to dry eye disease, to arthritis. Though some have touted omega-3s in their various forms as the answer to these conditions, much of that research has had conflicting results.

What are omega-3 fatty acids?

Before we answer that question, let’s first go over what omega-3s actually are – after all, we hear the name a lot, but rarely an explanation as to what it means.

Omega-3s are a group of polyunsaturated fatty acids. Fatty acid refers to the carboxyl group at the end of the molecules (-COOH) that gives them their acidity, and polyunsaturated means they have a backbone made up of carbon atoms, many of which are linked by double bonds. 

These kinds of fatty acids are important to bodily functions, such as in the building of cell membranes and hormone production. However, the only way that we can get them is through our diet.

There are three main types of omega-3s that we can get from our food or dietary supplements: both EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are found in seafood, and ALA (alpha-linolenic acid) is in things like plant oils and nuts. It’s the former two that are most often the focus of research. 

For example, a number of studies have indicated that intake of foods or supplements containing EPA and/or DHA could contribute to a lower risk of cognitive decline, including in cases of dementia and Alzheimer’s disease. However, that’s not across the board; others suggest that supplements in particular have no effect on risk, nor on slowing cognitive decline when it’s already happening.

There have also been several studies investigating the impact of omega-3 dietary supplements on eye health, such as for age-related macular degeneration; a large National Institutes of Health-sponsored study concluded that they neither prevented nor affected the disease.

Other studies looking at dry eye disease sound slightly more positive on the face of it, with one finding that dietary intake of omega-3s appeared to be associated with decreased presence of the condition in women. However, it’s not quite so clear cut for dietary supplements, with one recent study finding them no better than a placebo and the American Academy of Opthalmology stating that “fish oil supplements do not appear to benefit patients with dry eye.”

The evidence is inconclusive, and it’s been a similar story for some of the largest studies investigating the impact of omega-3s on another two of our major organs – the heart and the lungs. But what does the latest research in those areas have to say?

Heart health

Recent studies focusing on the effects of omega-3s on heart health have had a mixed bag of results to say the least, both in cases where they’re taken in by eating seafood or via dietary supplements.

A 2018 science advisory from the American Heart Association, which reviewed research on omega-3 intake through seafood and risk of cardiovascular disease, concluded that “1 to 2 seafood meals per week be included to reduce the risk of congestive heart failure, coronary heart disease, ischemic stroke, and sudden cardiac death, especially when seafood replaces the intake of less healthy foods.”

However, another review conducted in 2020 didn’t go quite so far as to apply that advice to everybody. Analyzing data from four cohort studies, covering over 191,000 people from 58 countries, the study agreed that two servings of fish per week, especially oily, resulted in a lower risk of heart disease – but only for people who either already had heart disease or were at high risk of it. They found the same couldn’t be applied to general populations.

That’s not to say you should stop eating fish though; it’s a major component of the Mediterranean diet, which has many science-backed benefits. Seafood also isn’t the only way to get omega-3s, so what’s the case for dietary supplements like fish and algal oils? 

The picture appears even less clear when it comes to the health benefits of popping an omega-3 pill, particularly when it comes to the prevention of heart disease in the general population – this body of research is very limited. Even in cases where existing disease (or high risk of it) is involved, recent studies can’t seem to agree; some say omega-3 supplements help, whilst others say they don’t do much – if anything – at all.


Lung health

The news might be slightly more positive when it comes to omega-3s keeping our lungs in check, according to the results of some recent research – although there are still plenty of “maybes” involved. 

A study of over 300 people, for example, found that omega-3s could help to slow the progression of pulmonary fibrosis, a disease involving scarring of the lungs. 

“We found that higher levels of omega-3 fatty acids in the blood, which reflects several weeks of dietary intake, were linked to better lung function and longer survival,” said researcher Dr John Kim in a statement. “Our findings suggest omega-3 fatty acids might be a targetable risk factor in pulmonary fibrosis.”

Kim cautioned, however, that clinical trials will be needed to figure out if the findings can translate to routine therapeutic use of dietary changes or supplements, and what their underlying mechanisms could be.

When it comes to the prevention of lung disease in the first place, another large study in healthy people found that higher blood levels of omega-3s could be associated with both a reduced rate of lung function decline, and with better lung function in general. The researchers think this could be down to omega-3s having anti-inflammatory properties.  

“This large population-based study suggests that nutrients with anti-inflammatory properties may help to maintain lung health,” said Dr James P. Kiley, PhD, director of the National Heart, Lung, and Blood Institute’s division of lung diseases, in a statement. “More research is needed, since these findings raise interesting questions for future prospective studies about the link between omega-3 fatty acids and lung function.”

Should I be getting more omega-3s?

It’s up to you whether you decide to up your omega-3 intake, but it’s always best to consult a healthcare professional, particularly for people taking medicine that affects blood clotting, or those allergic to fish or shellfish.

If neither of those apply, they should also be able to help you if you’re curious about supplements. There are a lot of different products out there, some of them great, some of them not so great.

There are so many different supplements available that it can be tricky to know where to even begin.
Image credit: Elena Barbaros/Shutterstock.com

“In a typical [fish oil supplement] product, only one-third of the total oil content is actually [omega-3 fatty acids]. Patients would need to take > 10 capsules to achieve a therapeutic dose (up to 4 g/day) of mixed [omega-3 fatty acids],” according to one scientific review. A healthcare professional should point you towards a suitable product, if they think that will work best for you.

In other words, taking omega-3s in any form is a dish best served from a well-crafted, tried, and tested recipe. 

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current. 

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.   

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