But a Dutch study revealed that giving patients with a history of heart disease margarine enriched with omega-3 oils appears to make no difference in preventing a repeat attack.
The 40 month study of more than 4800 patients comes as a disappointment for Unilever, the food giant that developed the margarines involved.
All of the men and women involved were aged between 60 and 80 and had suffered a heart attack around four years previously. Besides a variety of margarines, all of them also took standard drugs to combat heart attacks.
On Sunday German researchers told the conference that patients with chronic heart failure given injections of their own bone marrow stem cells have better heart function and live longer.
The beneficial effects of the cell therapy were seen within three months and continued for five years, according to findings from one of the biggest studies to date on using stem cell therapy to treat heart conditions.