When was the last time you ate an egg without feeling guilty about a soaring cholesterol count? Since the Sixties, when doctors first hypothesized that lowering blood cholesterol levels would prevent heart attacks and strokes, everyone in the Western world has become obsessed with the cholesterol content of every last morsel they put in their mouths. Even McDonald's has recently got in on the act, boasting the low fat content of their hamburgers in advertisements placed in medical journals like the Lancet. But recent evidence now shows that the neither cholesterol lowering drugs nor the recommended diet does anything to prevent heart disease and may even do harm.Epidemiologist Dr James McCormick, Dean of the School of Physics in Trinity College, and President of the Irish College of General Practitioners, along with fellow Trinity professor Petr Skrabanek have co-authored a book entitled Follies and Fallacies in Medicine (Tarragon Press, Glasgow). Although we do not agree with everything in the book, notably an utter dismissal of all forms of alternative medicine, they raise many interesting points about how the "science" of modern medicine is built upon faulty premises. In the following, which is adapted from their book, they lay the cholesterol myth to rest.

Since the Second World War coronary heart disease has become a much more important part of the lives of both doctors and lay people. Epidemiologists have expressed their interest by examining factors which are associated with an increased probability of developing coronary heart disease, so called risk factors. Risk factors, better called risk markers to emphasize that they are associated with an altered probability of developing disease rather than necessarily being causally related, have been described in numerous prospective and case control studies. At the moment some three hundred risk factors for coronary heart disease have been described and the list continues to grow. At the moment it includes: cigarette smoking, high cholesterol, high blood pressure, obesity, diabetes, low levels of high density lipoproteins, selenium, thiazide diuretics, not drinking, not exercising, not having siestas, not eating fish (especially mackerel), living in Scotland, speaking English as a mother tongue, having a high level of phobic anxiety, being scrupulous about keeping appointments, not taking cod liver oil, and snoring. The important associations include being male, a family history of the disease and perhaps most important of all, because it is alterable being poor in the rich world.

Because risk factors are associated with an altered probability of developing disease, it was assumed that an alteration in risk factors would reduce death and morbidity. This led to the believe that identifying risk factors in healthy populations would be a good thing to do. This has turned out to be a dangerous delusion. Dangerous because altering risk factors does little good and may do harm.

The best evidence about the effects of altering risk markers comes from controlled trials. In these trials, the risk status of half the population under study is altered by some intervention, while the other half continues as before; both populations are followed through time to see whether or not they develop disease. Almost all the studies to date have been concerned with middle aged men in whom the risk of coronary disease is reasonably high. Such studies are still difficult and expensive because large numbers of subjects need to be recruited and followed for many years.