There is strong evidence that omega-3 fatty acids from fish oil can lower cholesterol, help stave off Alzheimer's disease and make us smarter. High time, then, that we all switch over to the good oil.
There is barely a health-giving property that hasn't been ascribed to omega-3 fatty acids. They lower cholesterol, reduce the risk of heart disease, act as anti-inflammatories, make kids behave themselves and hold depression and dementia at bay. They even, a recent study found, make you sexier. About the only thing they don't do, it seems, is make you lose weight. Fish oil is no snake oil.
The investigation of the substance does, however, have a satisfyingly eccentric beginning in the form of one Hugh MacDonald Sinclair, the Oxford don who, in 1956, published a letter in the British medical journal the Lancet, asserting a difference between "good" and "bad" fats. Although some of his findings were a little off the wall, his letter generated heated correspondence in the journal's pages for a year afterwards.
It was his 1976 expedition to Greenland, however, that was the first link in the chain to omega-3. Puzzled by the lack of heart disease among the Inuit people, whose diet was extremely high in fat, Sinclair decided upon his return to the UK to put himself on an Inuit diet. He took no half-measures - he imported a whole seal, via the Danish Embassy, and for three months augmented that with fish and shellfish only: the Atkins Diet of the sea.
Dr Frank Ryan, author of The Eskimo Diet, points out that "this is a good deal less balanced than the real diet of the Eskimos"- but the results were dramatic. Sinclair's blood fats changed to the same low triglyceride levels he'd found among the Inuit, and he started to bleed alarmingly - Inuit are prone to nosebleeds.
Andre McLean, a former student of Sinclair, wrote later, "I remember having dinner with Hugh at Magdalen high table, an excellent meal, but Hugh ate his piece of grilled seal. He enjoyed his diet, he said, but when he pruned his roses his boots filled up with blood, because his clotting factors had been somewhat disturbed by the diet, and each scratch bled."
"This suggested," Ryan explains, "that not only did a fishy diet improve blood fats, it also reduced the risk of forming a blood clot - a major factor in heart attacks." Ryan co-authored The Eskimo Diet in 1990 with colleague Dr Reg Saynor, after Saynor - then running a lipid lab in Sheffield - saw Sinclair interviewed on television and decided to try it for himself. More sensibly, he stuck to cod-liver oil and, after a week, his high triglycerides had dropped to normal levels.
Fish oil is now one of the highest-selling supplements - uncontroversially recommended for good heart health by conventional and complementary medical practitioners alike. "Little did we realise," Ryan writes in his new follow-up book The Brain Food Diet, "that what we knew then, revolutionary as it seemed, was merely the tip of the iceberg."
Saynor turned 80 earlier this year, looking barely a day over 60 - a fact he credits to his 30-year fish habit.
The new research frontier for the benefits of omega-3 is the brain. The fatty acids are vital in its early development and, it now seems, in slowing its decline - but they also boost the day-to-day health of your mental faculties. And our diet doesn't contain nearly enough of them.
Professor William Harris is such an advocate, he shows off pictures of his car's "omega 3" vanity plates. "As you can see, I'm a fan," says the director of nutrition and metabolic diseases research at the South Dakota Health Research Foundation. His "omega-3 index" measures the percentage present in red blood cell membranes. If six percent of the membrane is omega-3, the omega-3 index is 6. Harris and his team have established that, for good cardiovascular health, 8 and up is the "beneficial" range. And what's good for your heart is good for your brain. Most westerners fall well below that - extrapolating from diet surveys, researchers here have determined that the average New Zealander's omega-3 index is 3.4.
The good news is that raising it is easy - improvements are usually noted, as Sinclair and Saynor can testify, within weeks of changing diet or taking fish oil supplements.
Ryan says that, since writing The Eskimo Diet with Saynor, he'd lost track a little of omega-3 research, and it wasn't until March of this year, when he was asked to check out the health claims being made about a new supplement, that he immersed himself in it again.
By telephone from his Sheffield home, he says that "within a week, I was utterly astonished at what I was discovering". This company, he says, had no particular bent towards reducing dementia or cognitive decline, but that is exactly what Ryan began to find.
An early brain-health barrier was broken in 2000 when it was discovered that, though breastfed babies had performed better in cognitive tests than those who were bottle-fed, "if you added cod-liver oil to the bottle-fed babies, essentially there was no difference. Which is utterly amazing, when you think about it."
And the benefits lasted at least into early childhood. A Norwegian study of 590 pregnant women found that the half who were given cod-liver supplements had larger babies with better brain maturation at birth. IQ tests conducted when the children were four years old found that those with cod-liver-oil mums scored significantly higher.
It's worth noting here that the fat that women store on their hips and bum is not actually evil - it's rich in omega-3, for nourishing children in utero. Less desirable fats are stored round the waist, which is why some researchers believe men are attracted to women blessed with hourglass figures: their high omega-3-ratio suggests - somewhat subliminally - that they're more likely to have intelligent offspring. Omega-3: sexy.
Ryan, who takes omega-3 for his arthritis, turned his attention to ageing, and, late last year, discovered a huge nine-year study, done in Framingham, USA, that had produced amazing results. It followed 899 elderly people who embarked on the study with no signs of dementia. By the end of the nine years, 99 of them had developed dementia, and of those, 71 developed Alzheimer's - what you'd expect, statistically, from a group that size.
But what they found when they looked into diet was extraordinary: what's called a dose-effect relationship between omega-3 intake and reduced risk of dementia. "In other words, the more people took, the better the effect." In the top quartile of that group in terms of omega-3 intake, Ryan goes on, there was a 50 percent reduction in dementia and a 40 percent reduction in Alzheimer's. "And those in the highest percentile were still not actually taking that much - it was the equivalent of a teaspoon of cod-liver oil a day - so we don't know whether you might have an even bigger reduction if you took even more."
The results were so exceptional that a large-scale, ongoing study into prevention of Alzheimer's, specifically, is under way.
Looking further into the much more widespread common-or-garden "cognitive decline", Ryan found even more good news. Cognitive decline is unlike dementia or Alzheimer's, which display specific patterns of brain disease; it's what many people will have experienced with elderly parents: "People get older and they become forgetful and lose control over things. Their hygiene falls, basically their life falls to pieces. Their families can't look after them, they go into old folks' homes and all the rest of it." A recent Dutch study took a group at highest risk of cognitive decline - men aged between 70 and 89 - and again found a dose-effect relationship between omega-3 intake and reduced risk.
The results were possibly even better than those of the Framingham study. An overall reduction of about 50 percent was found in the group, but in the top quartile, there was no cognitive decline at all. This is something we used to accept as a normal part of ageing, Ryan says, but now we know it isn't.
"There can be no denying these effects," Ryan insists. "These have been really high quality studies ... These are as good as you can get."
Late last year, an article in New Scientist declared: "No nutrient has garnered as much supporting evidence for promoting mental health as long-chain omega-3 fatty acids." How does it work? Sixty percent of your brain is fat and studies have shown, the report continued, that most of that fat goes into making the membranes that envelop nerve cells. "Studies have shown that [omega-3s] make the membrane much more fluid and flexible, rendering the cell more receptive to incoming signals."
The implications spread right across the field of mental health - New Scientist cited preliminary studies that have had "encouraging results for schizophrenia, borderline personality disorder, dyslexia, autism, attention deficit hyperactivity disorder, obsessive compulsive disorder and dyspraxia, among others".
The authors cautioned that these studies were still in their early days. However, they were enough for the American Psychiatric Association to recommend this year that all patients being treated for depression or bipolar disorder have omega-3 supplements added to their regular treatment programme.
Dr Natalie Sinn, of the University of South Australia, has been studying the relationship between omega-3 and the symptoms of ADHD. Last year, the results of her double-blind trial were published. Taking 100 children with ADHD, Sinn gave half of them a fish oil supplement and the other half a placebo. After just 15 weeks, the children on the supplements were shown to have "improved attention, improved hypoactivity and improved impulsivity". Parents and teachers reported better behaviour. The kids on the placebos were then put onto the supplements and, 15 weeks later, they showed the same improvements as the first group.
Last year, Sinn turned her results into an educational roadshow. Afterwards, she says, someone crunched the numbers, "and told me that fish oil supplement sales had gone up by $1 million!"
Although her preliminary results have been encouraging, Sinn is continuing her study of exactly how this mechanism works. Numerous studies have also been done on "normal" kids whose scores go up when they take fish oil. "We think it's an attention thing," she explains. What this doesn't mean, she's quick to point out, is that disorders like ADHD are caused by an omega-3 deficiency.
Never forget, she says, that although these huge studies are impressive, at the heart of the matter are individual lives. When the mother of Stephen, a 10-year-old boy with ADHD, saw Sinn interviewed about her study on Australian TV, she put him onto fish-oil supplements without telling him what she was doing. His results were extraordinary, his mum reported, for a young boy who'd written her a heart-breaking, almost illegible letter that said, "I'm sorry I'm so stupid." His improvement was in line with the findings of Sinn's study - better behaviour, a happier child, better test results. The two women were interviewed for another Australian news story and at the end, Sinn says, Stephen's mum "pulled two crumpled bits of paper out of her pocket". They were "before" and "after" handwriting samples - his writing is nearly perfect now.
"This is so simple," says Ryan. "It's such a simple message. Unlike all these messages where this is bad for you or that's bad for you, fried food's bad for you - cooked food's bad for you is the latest one, which is nonsense - this is it. This is the real McCoy."
The Brain Food Diet: www.swiftpublishers.com
The Omega-3 Centre: www.omega-3centre.com