Sunday, November 20, 2005



THE DANGEROUS SCARE ABOUT CHOLESTEROL

"If you eat too much cholesterol, or saturated fat, your blood cholesterol will rise to dangerous levels. Excess cholesterol will then seep through your artery walls causing thickenings (plaques), which will eventually block blood flow in vital arteries, resulting in heart attacks and strokes.... Scientific hypotheses don't get much simpler than this: the cholesterol, or diet-heart, hypothesis, which has broken free from the ivory towers of academia to impact with massive force on society. It has driven a widespread change in the type of food we are told to eat, and consequently the food that lines the supermarket shelves. Many people view bacon and eggs as a dangerous killer, butter is shunned, and a multi-billion pound industry has sprung up providing 'healthy' low-fat alternatives.

However, all is not what it seems. The cholesterol hypothesis can be likened to a cathedral built on a bog. Rather than admit they made a horrible mistake and let it sink, the builders decided to try and keep the cathedral afloat at all costs. Each time a crack appeared, a new buttress was built. Then further buttresses were built to support the original buttresses. Although direct contradictions to the cholesterol hypothesis repeatedly appear, nobody dares to say 'okay, this isn't working, time to build again from scratch'. That decision has become just too painful, especially now that massive industries, Nobel prizes, and glittering scientific careers, have grown on the back of the cholesterol hypothesis. The statin market alone is worth more than 20 billion pounds each year.

In reality, cracks in the hypothesis appeared right from the very start. The first of these was the stark observation that cholesterol in the diet has no effect on cholesterol levels in the bloodstream: 'There's no connection whatsoever between cholesterol in food and cholesterol in blood. And we've known that all along. Cholesterol in the diet doesn't matter at all unless you happen to be a chicken or a rabbit.' Ancel Keys PhD, professor emeritus at the University of Minnesota 1997.

A bit of a blow to a cholesterol hypothesis, you might think, to find that dietary cholesterol has no effect on blood cholesterol levels. However, as everyone was by then fully convinced that something rich and 'fatty' in the diet was the primary cause of heart disease, nobody was willing to let go.

So the hypothesis quietly altered, from cholesterol in the diet to saturated fat in the diet - or a bit of both. As if cholesterol and saturated fat are similar things. In reality, this could hardly be further from the truth. Saturated fat and cholesterol have completely different functions in the body, and they have very different chemical structures....

It is true that Ancel Keys appeared to have proven the link between saturated fat consumption and heart disease, but when it came to the major interventional trials, confirmation proved elusive. The MR-FIT trial in the USA was the most determined effort to prove the case. This was a massive study in which over 350,000 men at high risk of heart disease were recruited. In one set of participants, cholesterol consumption was cut by 42 percent, saturated fat consumption by 28 percent and total calories by 21 percent. This should have made a noticeable dent in heart disease rates.

But nothing happened. The originators of the MR-FIT trials refer to the results as 'disappointing', and say in their conclusions: 'The overall results do not show a beneficial effect on Coronary Heart Disease or total mortality from this multifactor intervention.'

In fact, no clinical trial on reducing saturated fat intake has ever shown a reduction in heart disease. Some have shown the exact opposite: 'As multiple interventions against risk factors for coronary heart disease in middle aged men at only moderate risk seem to have failed to reduce both morbidity and mortality such interventions become increasingly difficult to justify. This runs counter to the recommendations of many national and international advisory bodies which must now take the recent findings from Finland into consideration. Not to do so may be ethically unacceptable.' Professor Michael Oliver, British Medical Journal 1991

This quote followed a disturbing trial involving Finnish businessmen. In a 10-year follow-up to the original five-year trial, it was found that those men who continued to follow a low saturated fat diet were twice as likely to die of heart disease as those who didn't.

It is not as if this was one negative to set against a whole series of positive trials. In 1998, the Danish doctor Uffe Ravnskov looked at a broader selection of trials: 'The crucial test is the controlled, randomised trial. Eight such trials using diet as the only treatment has been performed but neither the number of fatal or non-fatal heart attacks was reduced.' As Ravnskov makes clear, no trial has ever demonstrated benefits from reducing dietary saturated fat.

Much more here

No comments: