Saturated fat and coronary heart disease

Part 5: Margarines increase cardiac risk

It is quite clear from both epidemiological studies and over half a century of clinical trials that saturated fats — particularly the traditional animal fats and tropical oils are not at all hazardous to our health.

With animal fats denigrated and with the backing of the medical world, the vegetable oil and food processing industries, the main beneficiaries of any research that found fault with competing traditional foods, began promoting cheap-to-produce vegetable margarines and cooking oils. These could now be sold at prices which rivalled the price of butter and animal fats.

In 1983 a multi-year British study, the WHO European Collaborative Trial in the Multifactorial Prevention of Coronary Heart Disease (CHD), involving 18,210 men aged between 40 and 59, showed clearly that eating these was ill-advised.[1] Men who switched to 'healthy' margarines and vegetable oils had twice the death rate of those on an 'unhealthy' saturated fat diet, even though the men on the saturated fat diet also continued to smoke. Despite this, the authors perversely reported that "There was no clear effect on hard CHD end-points (coronary deaths and myocardial infarction) or on all-causes mortality."

They continued: "However, there was a 36% reduction in the rate at which intervention subjects reported ill with other CHD (principally angina) during the study, and at the end fewer intervention men gave positive responses to a self-administered questionnaire on angina and chest pain." So was there some benefit? Apparently not; the authors say: "These apparent benefits were not substantiated by electrocardiographic evidence, suggesting that participation in a heart disease prevention campaign may bias reporting of symptoms." Ultimately, they ignored their own findings and presented a politically correct conclusion, saying: "The implication for public health policy in the U.K. is that a preventive programme such as we evaluated in this trial is probably effective. . . ."

Scientists at the Wynn Institute for Metabolic Research, London, UK, compared the fatty-acid composition of artery blockages. What they found was a high proportion of both omega-3 and omega-6 polyunsaturated fatty acids; what they did not find was saturated fatty acids. They suggested that "current trends favouring increased intake of polyunsaturated fatty acids should be reconsidered."[2]

Ten years later two further studies published simultaneously in the American Journal of Clinical Nutrition reinforced the findings that saturated fats actually protected against heart disease. The first found that a so-called 'healthy' carbohydrate-based diet increased the rate at which older women's arteries degenerated and that increasing intakes of saturated fat actually slowed down the progress of their atherosclerosis.[3] The second study found what its authors called a 'paradox' when they showed that

"a high-fat, high-saturated fat diet is associated with diminished coronary artery disease progression in women with the metabolic syndrome, a condition that is epidemic in the United States."[4]


1. Rose G, Tunstall-Pedoe HD, Heller RF. UK heart disease prevention project: incidence and mortality results. Lancet 1983; 1: 1062-6.
2. Felton CV, Crook D, Davies MJ, Oliver MF. Dietary polyunsaturated fatty acids and composition of human aortic plaques. Lancet 1994; 344: 1195-6.
3. Mozaffarian D, Rimm EB, Herrington DM. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr 2004; 80: 1175-84.
4. Knopp RH, Retzlaff BM. Saturated fat prevents coronary artery disease? An American paradox. Am J Clin Nutr 2004; 80: 1102-3.

Part 1: Keys | Part 2: Early studies | Part 3: Supportive studies? | Part 4: Other evidence | Part 5: Margarines | Part 6: Conclusion

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Last updated: December 9, 2011