A high fat diet, although linked to heart disease, does not increase the risk of a stroke, research suggests.

Researchers from Harvard School of Public Health monitored the diets of almost 44,000 healthy middle-aged men for 14 years.

Although 725 men had a stroke during the period of the study, the researchers found no link to dietary intake of any type of fat.

The research is published in the British Medical Journal.

The researchers also found no significant link between stroke and consumption of foods that are rich in both fat and cholesterol, such as red meat, nuts and eggs.

Lead researcher Dr Ka He said: 'Our study indicates that dietary fat may not be a strong predictor of stroke in men. Clearly, more research is needed.'

Previous research has suggested that a diet high in saturated fats is likely to lead to thickening of the arteries, which increases the risk of heart disease.

Complex disease

However, the researchers say that this thickening - known as atherosclerosis - is not a direct cause of a substantial proportion of a common type of stroke called an ischaemic stroke.

This occurs when blood flow to a particular part of the brain is cut off by a blockage - such as a clot - inside a blood vessel, may be caused by a variety of factors.

But they say the link between dietary fat intake and the risk of haemorrhagic stroke - another common form of the condition caused by bleeding in the brain - is far from clear.

Professor John Reid, head of the Cardiovascular Research School at Glasgow University, a link between fat intake and stroke could not be ruled out, but he said research into the area had proved to be inconclusive.

He told BBC News Online: 'Stroke disease can be caused by several different factors. Some are common to heart disease, but others are not, so maybe it is not so easy to isolate obvious causes.'

Prof Reid said some risk factors were common to both conditions. For instance, smoking increases the risk of heart disease and stroke.

However, high blood pressure and high alcohol consumption were much more closely linked to a heightened risk of stroke than of heart disease.

Jerry Doyle, of the Stroke Association said: 'We should be very cautious indeed about these results as the link between fat intake and cardiovascular disease is well proven and this paper does not alter the logic of the basic public health message telling people to avoid saturated fats.

'Basically, if you eat a diet of saturated fats and take in a lot of cholesterol, then you are definitely at increased risk of coronary heart disease.

'The possibility of it also applying to stroke has not been excluded and indeed the heart protection study has shown that lowering cholesterol when people have already had a stroke, certainly ischaemic strokes, helps protect against further strokes.'