It's a widely held belief that high cholesterol poses significant hazards to our health, and that trimming the level of this fat in the bloodstream can only help to ensure that life goes on. Food companies have been particularly keen to feed this notion and offer us an ever-expanding range of spreads, milks, yogurts and cheeses which promise to curb cholesterol levels.

Very recently, I read a survey from a leading food manufacturer which revealed that many of us are simply not paying enough attention to our cholesterol levels, and might be putting the health of our hearts at risk. The subtext of the piece of PR seems to be that those who take a laissez-faire approach to cholesterol have a death wish.

At first sight, the concept that quelling cholesterol levels has health-enhancing benefits does appear to be supported in science. Several studies show, for instance, that the statin type of cholesterol-reducing medications are effective in preventing heart attacks and strokes in individuals who have a history of cardiovascular problems. Crucially, such disease prevention - called 'secondary prevention' by the medical profession - seems to have overall life-extending benefits.

However, other evidence suggests that cholesterol reduction is not the panacea it is made out to be. Cholesterol is an essential building block in all of the body's cells and several important hormones. Lowering cholesterol levels seems to have the capacity to upset certain functions, including mood and behaviour: one study published in the British Medical Journal found that cholesterol reduction was associated with a 28 per cent increased risk of death due to suicide, violence or accident. There is also some evidence that it increases the risk of haemorrhagic stroke (one of the two main forms of stroke).

There is considerable doubt about whether the benefits of cholesterol reduction extend to individuals who are essentially healthy. Reducing cholesterol levels in such people - referred to as 'primary prevention' - tends not to bring the level of benefit seen in those who have a track record of heart disease and stroke.

Plus, there is always the possibility that any reduction in risk of cardiovascular disease may be outweighed by an increase in risk of other conditions.

The most comprehensive study assessing the effects of low-fat and cholesterol-reducing diets was published in the BMJ in 2001. This research - the results of 27 studies pooled together - revealed that changes to the amount and type of fat in the diet reduced the risk of death due to heart attack and stroke by just 9 per cent. Tellingly, overall risk of death (total mortality) remained unchanged.

And while the oft-prescribed statin drugs are known to offer benefits in terms of cardiovascular health, primary-prevention studies have failed to show that they reduce total mortality either. The evidence suggests that, for healthy individuals, cutting cholesterol does a fat lot of good.