Replacing foods high in saturated fats with polyunsaturated fats has long been recommended for a healthier heart, but researchers from the University of Kuopio in Finland say that few studies have provided scientific support for this advice.
Some metabolic studies show that polyunsaturated fats lower levels of low-density lipoprotein cholesterol in the blood while saturated fat increases LDL cholesterol.
David E. Laaksonen and colleagues assessed the dietary intake of linoleic acid (a liquid polyunsaturated fatty acid abundant in plant oils like flaxseed and linseed) and total polyunsaturated fatty acid intake with cardiovascular and overall rates of death in 1,551 middle-aged men living in eastern Finland.
They used food records and blood tests for glucose and serum cholesterol levels to compile the data, and tracked heart disease deaths over 15 years.
"Middle-aged men with proportions of serum linoleic acid, omega-6 fatty acids, and especially PUFA in the upper third were up to three times less likely to die of cardiovascular disease than men with proportions in the lower third," write the researchers in the 24 January issue of Archives of Internal Medicine (165, pp193-199).
Dietary intake of linoleic acid and total PUFAs as assessed with a four-day food record was also inversely associated with heart disease deaths but total fat intake was not.
The study lends further support to the trend of formulating with omega-3 and omega-6 ingredients.
"Dietary fat quality thus seems more important than fat quantity in the reduction of cardiovascular disease mortality in middle-aged men," conclude the researchers.
"Carrying out recommendations to replace saturated fat with polyunsaturated fat in the primary prevention of cardiovascular disease may substantially decrease heart disease death and to a lesser degree overall mortality," they add.
Heart disease kills more people around the world than any other disease, according to the World Health Organisation.
A Liverpool University professor recently recommended that cutting cholesterol levels by 10 per cent would save 25,000 lives in the UK every year.
Lifestyle changes are already responsible for a significant drop in mortality rates in the industrialised world over the last two decades, Professor Simon Capewell said, although coronary heart disease still kills 100,000 British people every year.