Omega-3 fatty acids are good for your brain and, it seems, for the heart too, writes Claire O'Connell
WHEN YOUR mother told you to eat up your fish to help keep you smart, she had a point: the omega-3 fatty acids in coldwater fish are brain builders. But to convince you to polish off your salmon she could also have mentioned that fish oils are a key to a healthy heart.
It's a link that has exercised Swedish pathologist Prof Tom Saldeen since he attended a scientific meeting in 1980, and heard from a Danish colleague that Greenland Eskimos seldom suffer from cardiovascular disease.
"His hypothesis at that time was that it was due to the diet - the Eskimo diet is known to be very fat-rich and his hypothesis was that it was the good fats they had, the omega-3 fats," says Saldeen, professor emeritus at Uppsala University.
"I returned home to Sweden and we started to find out if omega-3 fatty acids might have anything to do with Swedish heart disease," he explains. "And what we found in Sweden was that people with cardiovascular disease have low levels of omega-3 fatty acids in their body or blood, compared to healthy people and people with other causes of disease."
Further studies on animals and humans highlighted a link between low omega-3s and sudden cardiac death, which piqued Saldeen's interest further. And his studies on sudden cardiac death showed that the best type of fish oil supplement was a "stable" one.
"When you produce a fish oil, to get it clean you have to remove a lot of toxic substances such as mercury and dioxins, and during this process you also lose other important things, especially the antioxidants," he explains.
"So we looked at fish oils where they have been carefully produced by restoring the original antioxidants like vitamin E. And the stable fish oil works much better in preventing sudden cardiac death in animals."
In human trials, the stable fish oils also slashed levels of warning-sign fats called triglycerides in the blood, and had a profound effect on cholesterol profiles, says Saldeen.
"It transforms the cholesterol - there are two types of 'bad' cholesterol: one which is a bigger particle and is not very dense, called LDL-A and then LDL-B, which is the bad one, a small, dense particle which can penetrate into the vascular wall and produce atherosclerosis [ a build up of plaque in the arteries]," explains Saldeen. "With fish oil you have a dominance of the LDL-A particle."
So how do the omega-3 fats work their magic? It's down both to their shape and to the types of hormone our bodies can build from them, explains Saldeen.
"There are two major mechanisms behind the effects of omega-3 fatty acids. One is a structural change because the EPA and the DHA [ the main beneficial omega-3 fats] are not straight - they look like a number '6' whereas saturated fats look like a number '1'," he says.
Having the curly '6'-shaped omega fats rather than the straight '1'-shaped saturated fats in the membranes that surround our cells makes those membranes more flexible and better able to function, he explains.
Meanwhile, the omega-3 fatty acids also provide the basic raw materials for our bodies to build beneficial hormones and anti-inflammatory agents, he adds.
And while coldwater fish like salmon, mackerel, trout, sardines and fresh tuna provide the lion's share of EPA and DHA in our diet, Saldeen believes that what we get from the dinner plate is not enough.
His research has been used to promote brands of stable fish oil, including Eskimo-3 and Eskimo Kids, produced by Uppsala-based pharmaceutical company Cardinova. He is currently working with Cardinova as a consultant, although he says he had no economic ties with them at the time of doing the research.
"We developed a method of measuring the omega status in the body, with just one drop of blood from the finger," says Saldeen, describing how a particular index of omega-3 correlates with a reduced risk of sudden cardiac death.
"But we have seen exceptionally few people who can reach that index without having a supplement. You can increase the level by a certain amount by increasing the intake of fish of course. But I have lots of patients who have been having these tests for several years, and I have found that an ordinary person usually gets to this index by taking 5 millilitres every morning of stable fish oil. I do it myself, as do my friends and colleagues."
However, despite the benefits to heart health, the potential blood-thinning effects of EPA supplements have raised concerns in the past over bleeding problems for patients who are already taking blood thinners such as warfarin or aspirin. But Saldeen believes that if the fish oil is of the natural and stable variety, this should not be a problem.
So how can a consumer know which fish oil supplement to choose from the banks of brands that sit on chemist, healthfood shop and even supermarket shelves? It's difficult, agrees Saldeen, but the best way to identify a natural, stable fish oil is to put it to the taste test.
"The best way is to taste the oil. It should have no bad taste because that indicates that it is rancid," he says. "With a liquid there's no problem, and if you have a capsule you can bite it to taste it."
Prof Tom Saldeen will give a talk entitled Omega-3 and your heart. . . perfect partners for a healthy life! this Saturday, September 6th at 5pm, and again on Sunday at noon at the Rude Health exhibition in the RDS.
• Prof Saldeen's talks in Dublin are sponsored by Galway-based PPC Ltd, which distributes Cardinova fish oil products in Ireland.
Tickets to Rude Health cost €10 (50 per cent discount vouchers available in IAHS stores in August). For more information visit www.rudehealth.ie