Science - November 29, 2011

Omega-3 helps diabetes patients who had heart attack

Text:
Astrid Smit

Diabetes patients who had suffered from a heart attack can benefit from omega-3 fatty acids. These food substances lower the risk of getting acute arrhythmia (irregular heart rhythm), researchers in Human Nutrition conclude in the Diabetes Care magazine this week.

Omega-3 fats are found in fish and vegetable oils such as those in soya beans and linseeds. Their workings have been extensively tested in the last ten years in the Alpha Omega Trial. They are said to have a positive effect on heart and cardiovascular diseases, so goes the thinking. But this study, published last year in The New England Journal of Medicine, could not confirm this claim. Test persons who consumed margarine with good fatty acids for more than three years were not better off than test persons given margarine without these fatty acids. But a very thorough analysis has now shown that a subgroup did benefit from these fats: diabetes patients who had suffered a heart attack in the past; they number more than 150,000 in the Netherlands.

Heart failure
Diabetics given margarine with good fatty acids had seven times less chances of getting acute arrhythmia than those given margarine without extra omega-3 fatty acids. In addition, the risk of getting a heart failure also went down for these patients, who were also less frequently hospitalized for the placing of an implantable defibrillator. This is a device which monitors the heartbeat and takes action when irregular heart rhythm is detected.
The omega-3 fatty acids, however, do not lower the risk of getting a heart attack. 'Apparently, they are good for transmitting electrical signals in the heart, resulting in less chances of acute arrhythmia, but omega-3 fats have not shown any verifiable effects on atherosclerosis in the arteries, the major cause of fatal heart attacks,' says Professor Daan Kromhout of Public Health Research in Wageningen UR and research leader in the Alpha Omega Trial.
Too early
The numbers involved in this study were small: only 1014 diabetes patients, of whom 56 had serious heart problems. It is therefore too early to draw definite conclusions, says Kromhout. 'A separate trial which solely looks at diabetics who have had heart attacks in the past is needed to make sure that the effect is present.'