Research has already suggested on several occasions that eating fatty fish and supplementing with fish oil can reduce the risk of having a heart-attack.
But according to studies published in Circulation (2004;110:368-73) and Prostaglandins, Leukotrienes, and Essential Fatty Acids (2004;71:153-9), evidence points to the possibility that these fats might also prevent dangerous abnormalities in heart rhythm.
In the first of the new studies, 65 people with arrhythmia were randomly assigned to receive either three grams of fish oil (providing one gram of omega-3 fatty acids) per day or placebo for six months. Blood tests were then performed and heart rhythms were assessed during the six-month trial and for six months after stopping the supplements.
Compared to the beginning of the study, people receiving fish oil had significantly fewer and less severe arrhythmias. People taking fish oil had 46.9 per cent, 67.8 per cent, 71.8 per cent, and 100 per cent fewer occurrences of the four types of arrhythmia monitored in the study, namely atrial premature complexes, ventricular premature complexes, couplets and triplets.
Six months after the patients stopped taking the fish oil, these improvements were reversed and all measurements were similar to those from the beginning of the study. People receiving placebo experienced no significant changes in arrhythmia frequency during the study.
The second study involved 4,815 people over the age of 65 years, who were monitored for a potentially serious type of arrhythmia known as atrial fibrillation. They were followed for 12 years through annual physical exams and electrocardiographs to assess heart rhythms, and through reviewing records from all hospital visits.
Frequent fish eaters were found to have a lower risk of developing atrial fibrillation than people who were not. Compared to those who ate fish less than once a month, patients who ate fish once to three times a month were 24 per cent less likely to suffer atrial fibrillation, patients who ate it one to four times per week were 30 per cent less likely to suffer, and eating fish five or more times a week reduced the risk by 35 per cent.
The researchers therefore concluded that in elderly people, eating fatty fish reduced the risk of atrial fibrillation, and in people with existing arrhythmias, supplementing with fish oil reduced the number and severity of episodes of arrhythmia.
This research is another boost for the health giving properties of fatty acids, which earlier this week were awarded a qualified health claim by the US Food and Drug Administration. This means that conventional foods in the US will now be able to display a qualified health claim - previously restricted to supplements - for omega-3 fatty acids.
The FDA said that foods containing eiscosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) omega-3 fatty acids can carry a claim stating that they may help to reduce the risk of coronary heart disease (CHD).
"Coronary heart disease is a significant health problem that causes 500,000 deaths annually in the US," said Dr. Lester Crawford, acting FDA commissioner. "This health claim should help consumers to improve their health by identifying foods that contain these important compounds."
In 2000, the FDA announced a similar qualified health claim for dietary supplements containing omega-3 fatty acids.
The FDA recommends that consumers not exceed more than a total of 3 grams per day of EPA and DHA omega-3 fatty acids, with no more than 2 grams per day from a dietary supplement.
Of all the functional food ingredients available, the future looks most promising for omega-3 polyunsaturated fatty acids (PUFAs), particularly in the US, according to recent research by consultancy firm Frost & Sullivan. The research commented that while the more mature European omega-3 PUFA market was likely to stabilise at an annual growth rate of eight percent, some key market participants in the US are experiencing growth rates of over 20 percent.
Kathy Brownlie, an industry analyst from Frost & Sullivan, explained omega-3 has such growth potential because of the health benefits it is regularly purported to bring.
"Increased media coverage and product availability have helped differentiate omega-3 and omega-6 PUFAs from saturated fats, promoting omega-3 PUFAs as 'good fats', which are an essential part of the diet," she said. "Most industry experts agree that more omega-3 PUFAs need to be incorporated into our diets."
Scientific evidence is growing to substantiate the role of omega-3 PUFAs not only for protecting heart health but also prevention of cancer and other diseases.
The ingredient has moreover seen support from low-carb diets such as Atkins, which promotes omega-3 fatty acids as part of their eating plans.