Current evidence does not support guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.

The effects of different kinds of fats and food oils on health may have been exaggerated, researchers warned last night.

The latest analysis casts doubt on advice to avoid the saturated fats found in dairy foods.

And it casts further doubt on the benefits of oils extracted from plants, finding some limited evidence for the benefits of fish oils.

Researchers at Cambridge University, UK, set out to compare saturated fats with the polyunsaturated fats, such as omega 3 and omega 6, found in plant oils and fish.

Their analysis of more than 72 pieces of research involving studying the diets of more than 600,000 people concluded there was no link between total levels of saturated fat in the diet and risk of heart disease.

There was even evidence that one dairy fat, margaric acid, was linked to a reduced risk of heart disease.

Reporting in the Annals of Internal Medicine, the researchers say there is "weak" evidence linking animal fats to increased risk of heart disease.

There was also "some" evidence that the two omega-3 oils found in fish, eicosapentaenoic and docosahexaenoic acids, are linked to reduce heart disease risk.

Researcher Dr Rajiv Chowdhury said: "In 2008, more than 17 million people died from a cardiovascular cause globally. With so many affected by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence."

Professor Jeremy Pearson, associate medical director of the British Heart Foundation, called for "large-scale" clinical studies to come to give conclusive answers to the link between fat in the diet and heart disease.

He said: "This analysis of existing data suggests there isn't enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease.

"Alongside taking any necessary medication, the best way to stay heart healthy is to stop smoking, stay active, and ensure our whole diet is healthy – and this means considering not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables."

Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk. Annals of Internal Medicine 18 March 2014