Omega-3 can do everything from beating depression to boosting your brainpower and whittling your waist

WITH so much conflicting advice on the health benefits of different foodstuffs, it is tempting to pull up the duvet and let the goji berries, white tea and hemp seeds fly over our heads.

But it's hard to ignore the heat around omega-3 fatty acids, which seem to add an impressive new achievement to their CV every day.

These wonder acids are found in oily fish, eggs, milk and cheese as well as the wilder shores of flax seeds, walnuts and soya beans.

The most useful active ingredients are the long-chain fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

Experts say that, for adults, EPA is the crucial one, so make sure any tablets you buy have a high percentage. Some are as low as 30 per cent. Don't bother with omega-6 supplements. We eat enough of this already.

And if the thought of easing depression, reducing your risk of heart disease and boosting your brainpower is not attractive enough, remember that omega-3 plumps up the skin and may help the body burn fat.

Dr Nicholas Perricone, the influential American dermatologist, is adamant that eating plenty of essential fatty acids banishes wrinkles and nourishes the complexion.

He regularly puts patients on what he calls "the three-day face lift diet", packed with oily fish, nuts, lean meat and other omega-3 rich foods.

The improbably young-looking 46-year-old Elle Macpherson, left, even swears by them to help tone her stomach and waist. And who doesn't want a bit of whatever she's having? n

Omega-3 may be able to replace traditional drugs in the treatment of depression. Researchers from the University of Illinois have found that EPA has impressive results for patients with mental health issues, including schizophrenia.

They also found that people with omega-3 in their diets had much lower rates of depression than those who were deficient in essential fatty acids. Pregnant women are also less likely to suffer from post-natal depression.

Forth Valley Psychotherapy Services have had great success in the use of omega-3 in the treatment of medium to severe depression, and recommend taking a supplement with the highest possible percentage of EPA.

A recent study on rats has shown that taking omega-3 can make the breast cancer drug tamoxifen more effective. A combination of the drug and the fatty acids reduced the genes that produce tumour growth and the spread of cancerous cells. According to one of the researchers: "If a tumour was being treated with tamoxifen, the addition of an omega-3 fatty acid diet seemed to make the tumour, at least at the molecular level, more benign and less aggressive and responsive to tamoxifen."

There are now further studies on how taking omega-3 fatty acids can affect women's risk of developing breast cancer, which now affects one in eight of the female population.

Heart experts recommend omega-3 fatty acids for everyone, not just those who have, or who are at risk of, cardiovascular disease. For once, scientists agree that long chain fatty acids are beneficial to heart health, which means manufacturers can mention this on their packaging and advertising.

The fatty acids decrease the risk of arrhythmias, abnormal heartbeats that can lead to sudden death. They also decrease the level of triglyceride, a type of fat, in the blood and slow the growth rate of fat deposits in the artery walls. Omega-3 even slightly lowers blood pressure. EPA, in particular, seems to lower cholesterol levels.

One of omega-3's main claims to fame is that it helps the brain, which is 60 per cent fatty acids.

Sales of supplements for children soared after a six-month study in Durham seemed to show 40 per cent of underachieving children who took regular supplements saw an improvement in their school work.

Dyspraxia, dyslexia, ADHD and dementia are just some of the conditions it appears to help. Other children improve their concentration, handwriting and spelling. At the other end of life, DHA appears to delay, or even prevent, memory loss associated with Alzheimer's.

There is very strong evidence that the anti-inflammatory properties of fish oils ease tenderness in people suffering from rheumatoid arthritis and osteoarthritis.

It seems omega-3 stimulates the formation of anti-inflammatory compounds, eicosanoids, which soothes pain and reduces stiffness. The oils also seem to reduce age-related macular degeneration, a major cause of sight deterioration in the over-50s.

This article was first published in Scotland On Sunday, 17 April, 2011