Heart disease is the leading cause of death in the developed world. Although this disease employs more doctors than any other branch of medicine, recent discoveries show some fundamental flaws in our understanding of it — particularly the basic view, held by all of medicine, that fatty foods and high cholesterol are the main culprits.
The established view of coronary heart disease (CHD) rests on three propositions: 1) CHD is mainly the result of a high-fat diet; 2) high fat intakes lead to cholesterol in the blood, which sticks to arterial walls, causing heart disease;
3) cholesterol-reducing drugs (statins) save lives.
These three foundation stones of the heart-disease 'industry' comprise an informal, but mutually reinforcing, alliance of cardiologists, food manufacturers and drug companies. However, more and more doctors believe that the whole edifice is, if not yet crumbling, then certainly built on unsafe ground, for there's growing evidence that all three propositions are, quite simply, wrong.
The received wisdom is that 'saturated fats' - mainly from animals-are the major culprits in CHD. The origin of the theory goes back to the 1950s, when US nutritionist Ancel Keys did an international comparison of food intake and disease. Focusing on only six countries, he found that the ones with the highest per capita fat consumption had the highest rates of CHD (Lancet, 1957; i: 959).
From these limited data, medicine developed the whole saturated fat cholesterol atherosclerosis CHD hypothesis. But the data were incomplete. We now know that if Keys had included data from 22 countries (also available at the time), the fat-CHD connection would have disappeared.
Later alerted to the error, Keys tried to retract his earlier conclusions, but to no avail. His theory had already taken root within medicine as well as the food industry, where the low-fat revolution was already in full swing, promoting cheap, low-fat, processed foods as the new 'healthy' way to prevent heart disease.
High Fat vs Low Fat
One piece of evidence often used to support the fat-cholesterol-CHD connection is the Framingham Heart Study (from a small town in Massachusetts where the health records of its 6000 population have been collated every five years for the last half-century). However, the small-print data are often neglected for, although a link between total blood cholesterol and risk of CHD has been found, there is no connection between fat intake and cholesterol-in fact, quite the reverse. As Framingham study director Dr William Castelli observed, ". . . the more saturated fat and cholesterol one ate, the lower the person's blood cholesterol" (Arch Intern Med, 1992; 152: 1371-2).
That revelation has recently been buttressed by a little-known clinical study that has further blown a hole in the conventional theory. Doctors at Duke University compared the effects of two strict diets on 120 overweight people with high blood-cholesterol levels. For six months, 60 of them followed a low-fat/low-cholesterol diet, the rest followed a low-carbohydrate diet that allowed "unlimited amounts of animal foods . . . and eggs", plus a few selected low-carb vegetables.
On analysis, the researchers found that the low-carb dieters chose to eat so much meat that, on average, they consumed a staggering average of 68 per cent of their daily energy intake from fat. And yet, after six months, their blood triglycerides (fats) were actually lower than before and, even more surprising, lower than those on the low-fat diet. What's more, although their cholesterol levels were higher, it was mainly the 'good' HDL cholesterol that increased, with only insignificant rises in the disease-related, 'bad' LDL cholesterol. The high-fat dieters also managed to lose twice as much weight as the low-fat dieters (12.9 vs 6.7 per cent, respectively) (Ann Intern Med, 2004; 140: 769-77).