The benefits of fish oil: Why you should pay attention to your omega-3 intake

Debates over the benefits of fish oil are never far from the headlines - here's our guide to the latest research

Mackerel fillets, with all the benefits of fish oil
(Image credit: Getty Images)

The benefits of fish oils have been at the top of the health news agenda for decades.

Found predominantly in oily fish such as mackerel, trout and salmon, the omega-3 fatty acids EPA and DHA in particular, have been linked to a range of health benefits including boosting heart and brain health.

The American Heart Association recommends that we should eat at least two portions of fish a week in order to get these health-giving omega-3 fatty acids. 

But what if you don’t like fish? Are there health benefits of fish oil supplements with omega 3? That’s where the picture becomes less clear. Below, we take a look at some of the latest research on the benefits of omega-3 fish oils containing EPA and DHA.

The benefits of fish oil for heart health

People from countries with diets rich in omega-3 foods including fish and seafood - such as Japan and Greenland - show a lower risk of heart disease than Western countries such as the US and the UK where less is typically eaten. What's more, the UK NHS acknowledges the beneficial effect of the long chain omega 3 fats (EPA and DHA) on maintaining a healthy heart.

But what about fish oil supplements? A series of recent studies have called into question their heart-protecting qualities, including a major review of randomised studies in 2018 which showed omega 3 supplements had little or no effect on the risks of experiencing heart disease, stroke or death.  

But the story doesn’t end there. In 2019, another large study was published showing that taking a high dose supplement of pure EPA could reduce heart attacks, strokes and cardiac deaths in a high-risk population by over 25%. So where does that leave us? Dr Alex Richardson, a passionate advocate of the benefits of fish oil for health, says: “There is solid scientific evidence that the omega 3 from fish oils - DHA and EPA, and especially EPA - is beneficial for a healthy heart. 

“The reason you get so many seemingly conflicting results with nutritional studies can be to do with the limitations of those studies - often reflecting budgets, practicalities or the ethics of trials on humans - but also because clinical trials vary so much in the populations studied - formulations and dosages used, outcome measures and compliance. 

“Whenever possible, it's always best to get nutrients from real food, rather than supplements. But for those who can't or won't eat fish and seafood at least twice a week or more, supplements can help to increase blood and tissue levels of these omega 3. International scientific experts recommend at least 500mg/day of EPA and DHA for general heart health in the general population.”

Fish oil supplements

(Image credit: Getty Images)

The benefits of fish oil for women – pregnancy and breastfeeding

The NHS recommends pregnant and breastfeeding women eat at least one portion of oily fish a week as omega 3 fatty acids EPA and DHA help a baby’s nervous system to develop. (Although note they set an upper limit of two portions of oily fish and recommend certain fish to avoid.) But what if you don’t eat fish?

Dr Richardson says: “In 2018, a systematic review of randomised clinical trials showed that supplementation with omega-3 EPA and DHA during pregnancy reduces premature births and low birth weight. Prematurity and low birth weight raise the risk of physical and mental health disorders across a child’s life so pregnant women (and those of child bearing age) would do well to ensure they eat at least two portions of fish a week - one of which should be oily - or take an omega 3 supplement containing EPA and DHA omega-3s.”

If choosing a supplement, she advises looking for one that provides at least 250-300mg DHA and to ensure it states it is safe for use in pregnancy. “Some supplements, such as cod liver oil, can contain high doses of vitamin A and D which can be harmful in excess."

The benefits of fish oil for depression

A large and much publicised review of randomised trials by the University of East Anglia in 2019 found that omega-3 supplements offer little or no benefit for depression. However, Dr Richardson believes omega 3 supplements containing EPA in particular, can be beneficial. 

“The University of East Anglia review includes only trials lasting at least 6 months – most of which were not studies of depression or anxiety, but large trials of completely different conditions. 

"Other systematic reviews show that the effect of EPA-rich supplements in people with clinically diagnosed depression is usually between one and two times as big as the effect of antidepressants – and may enhance the effects of these medications. 

"By contrast, DHA-rich formulations, or studies in non-clinical populations, show little or no benefits. 

“Since 2006 the American Psychiatric Association has recommended at least 1g per day of EPA/DHA for depression and other mood disorders. And in 2019, a new consensus review of the latest research from leading international researchers and psychiatrists set out detailed clinical guidelines, recommending 1-2g per day of EPA (ignoring DHA) for patients with clinical depression."

However, she stresses: “Omega-3s are NOT a substitute for medication. In fact, they seem to work in synergy with antidepressant medications.” Do always seek the advice of your doctor before supplementing though.

The benefits of fish oil for skin and hair

Could omega-3 have benefits for our skin and hair? Perhaps. Studies into the benefits of omega-3 for skin are limited and mixed, but there is some evidence that they may be beneficial for skin conditions such as eczema and psoriasis - although further research is needed.  

There is also some evidence of the benefits of fish oil for hair - in reducing hair loss and promoting growth. But again, further research is needed.

The benefits of fish oil supplements

The evidence on the benefits of omega-3 supplements is constantly changing and evolving and is hotly debated, so always discuss with your doctor before taking any supplements especially if you suffer from any health conditions or are on any medication.