Eating margarine increases the risk of death and heart disease but there is no such link with butter and eggs, according to a new study.

Scientists said research showed that trans fats – industrially produced from plant oils and found in products from margarine to snack foods – had no health benefits and raised the risk of death by any cause by a third.

But saturated fats, found in animal products including milk and meat, were not linked to increased risk of death, heart disease, stroke or Type 2 diabetes.

Government guidelines advise people cut down on saturated fats to avoid heart disease but the research, published in the British Medical Journal, is the latest in a series of studies which question the notion saturated fat is bad for heart health.

Lead researcher Russell de Souza, an assistant professor in the Department of Clinical Epidemiology and Biostatistics at McMaster University in Canada, said: “For years everyone has been advised to cut out fats. Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear.

“That said, we aren’t advocating an increase of the allowance for saturated fats in dietary guidelines, as we don’t see evidence that higher limits would be specifically beneficial to health.”

The researchers analysed the results of 50 observational studies into links between the two types of fats and adult health and found no association between higher saturated fat consumption and a greater likelihood of stroke, heart disease and death.

But nor did they find evidence that diets high in saturated fat reduced the heart disease risk.

Trans fats, by contrast, were associated with a 34 per cent rise in death from any cause, 28 per cent increase in death from coronary heart disease and an overall 21 per cent hike in the risk of developing heart disease.

Cardiovascular disease causes more than a quarter of all deaths in the UK, while current prevention guidelines advise men should eat no more than 30g of saturated fat a day, while the maximum for women should be 20g.

De Souza added: “If we tell people to eat less saturated or trans fats, we need to offer a better choice. Unfortunately, in our review we were not able to find as much evidence as we would have liked for a best replacement choice, but ours and other studies suggest replacing foods high in these fats, such as high-fat or processed meats and doughnuts, with vegetable oils, nuts, and whole grains.”