Most healthy adults do not need to take Omega-3 supplements and can get as much of the fatty acids as they need from their diet, an expert has revealed.

The popularity of such products has soared with proven health benefits including maintaining blood pressure, heart function and healthy blood fat levels. 

The body cannot make these essential fatty acids naturally, meaning we have to get them from our diet or from supplements.

But most people can achieve the advised intake through eating oily fish regularly, registered nutritionist Emma Bardwell has told the Daily Mail.

'If you're regularly eating oily fish and following a varied diet, you probably don't need a daily Omega-3 supplement,' she said. 

'But if you never eat fish, rarely eat it, or are vegan, an Omega-3 supplement containing EPA and DHA is worth considering. 

'That's particularly relevant during pregnancy and breastfeeding, because DHA plays an important role in a baby's brain and eye development.' 

DHA (docosahexaenoic acid) is a key member of Omega-3 involved in brain function - or a placebo - and research conducted earlier this year found that its levels in fluid around the brain increased by around 17 per cent after six months of use.

Ms Bardwell added that DHA becomes 'particularly important' when a mother is pregnant or breastfeeding, and advised taking two portions of oily fish per week. 

'DHA makes up the structure of the brain and retina, and a mother's intake contributes to her baby's neurological and visual development,' she continued.

'Evidence also suggests that increasing long-chain Omega-3 intake during pregnancy can reduce the risk of preterm birth, particularly in women with low baseline intake.'

Omega-3 can also be pivotal during perimenopause and menopause, according to Ms Bardwell, because it helps to lower triglycerides, a common type of fat found in a person's blood and body.   

She said: 'As oestrogen levels decline, women's cardiovascular risk tends to increase. EPA and DHA can lower triglycerides, although the doses used therapeutically are considerably higher than those in ordinary supplements. 

'There's also interest in Omega-3s for mood, cognition and joint health, but the research isn't conclusive. We certainly don't have convincing evidence that Omega-3 supplements treat hot flushes or prevent dementia.'

'Omega-3 is just one piece of the puzzle,' she adds. 'Fibre, adequate protein, resistance training, sleep and overall dietary quality all matter enormously for healthy ageing.'

But more Omega-3 does not necessarily mean the user will see more benefits.  

Trials have found that some high-dose supplements can cause an increased risk of atrial fibrillation - a common heart rhythm disorder which can cause beats to become chaotic and out of sync. 

Omega-3 can also interact with medicines, according to the nutritionist, meaning large doses are not always necessarily harmless. 

'UK guidance suggests around 450mg of combined EPA and DHA daily,' Ms Bardwell continued. 'Although many clinical trials use closer to 1,000mg. 

'That higher dose isn't necessarily more beneficial for everyone. I'd always recommend checking the amount of EPA and DHA on the label rather than simply looking at the total fish oil content.'  

Diets rich in Omega-3 fatty acids, such as the Mediterranean diet, have long been linked to health benefits for the heart, brain and other organs.

For those who do take a supplement, Mel Lawson, founder of omega-3 brand Bare Biology, says the biggest pitfall is on the front of the bottle.

'One of the biggest misconceptions is that if a fish oil bottle says '1,000mg', you're getting 1,000mg of omega-3,' says Mel. 'Often, that figure refers to the total weight of the fish oil, not the actual amount of omega-3 it contains. The actual amounts of EPA and DHA are what matter.'

This is partly due to the fact that the body cannot make these essential fatty acids, meaning we have to get them from our diet.

Some studies have found that those with higher blood levels of Omega-3 fatty acids have better cognitive function. Others, however, suggest that giving people who already have dementia Omega-3 supplements will not boost their mental capacity.  

The latest study - published in the journal eBioMedicine - followed 365 adults, aged 55 to 80-years-old who rarely ate fish and were considered at risk for Alzheimer's.

Around half of participants carried the risk APOE4 gene - the strongest genetic risk factor for the disease.

Participants were randomly selected to receive either daily fish oil supplements - containing 2,000mg of DHA. 

Researchers, from the USC Center for Personalised Brain Health, found that DHA levels in fluid around the brain increased by around 17 per cent after six months, confirming the essential nutrient reached its intended target.

Two years later, participants underwent a number of memory and cognition tests and brain scans to see if their brain had shrunk since the beginning of the study.

Results showed there was no difference in cognitive performance between those who took a daily supplement and those given a dummy pill.

Brain scans also showed the supplements failed to protect against brain shrinkage, particularly of the hippocampus - the brain area responsible for memory.

The researchers concluded that while the supplements can reach the brain, Omega-3s may work better as a part of a Mediterranean-style diet, rather than a standalone supplement.