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 seem to have been particularly keen to feed this notion, and offer us an ever-expanding range of spreads, milks, yoghurts and even cheeses which promise to curb cholesterol levels. Very recently, I read a survey from a leading manufacturer of such foods which revealed that many of us are simply not paying enough attention to our cholesterol levels, and might therefore 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 an attitude to die for.
At first sight, the concept that quelling cholesterol levels has health-enhancing and life-extending benefits does appear to be supported in science. Several studies show, for instance, that the statin-type of cholesterol-reducing medications are really quite effective in preventing heart attacks and strokes in individuals who already have a history of such cardiovascular problems. Crucially, this type of disease prevention – referred to as ‘secondary prevention’ by the medical profession – seems to have overall benefits in terms of extending lives too.
However, other evidence suggests that cholesterol reduction is not the panacea it is often made out to be. Cholesterol is an essential building block in all of the body’s cells and several important hormones too. Lowering levels of cholesterol in the body 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 reduction in cholesterol levels increases the risk of haemorrhagic stroke (the less common of the two main forms of stroke).
While cholesterol reduction seems to have broad benefits for those with a history of cardiovascular disease, there is considerable doubt about whether these benefits extend to individuals who are essentially healthy. Reducing cholesterol levels in such individuals – 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 on health was published in the British Medical Journal in 2001. This research, in which the results of 27 individuals studies were 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 overall. Tellingly, however, overall risk of death (total mortality) remained unchanged. And while the much-touted and oft-prescribed statin drugs are known to offer benefits in terms of cardiovascular health, primary prevention studies have so-far failed to show that they reduce total mortality either. Some would have us believe that cholesterol is a curse than needs to be banished from the body. However, the evidence suggests that, for essentially healthy individuals, cutting cholesterol does a fat lot of good.