Saturated fat and coronary heart disease

Part 4: Other evidence

If heart disease really did result from eating saturated fats — as we are told — it would be reasonable to expect to find more heart disease in the nineteenth century when the fats we ate were all from animal sources; and we could have expected a decrease in heart disease with the introduction of vegetable-based margarines and consequential reduction in intakes of butter and other animal fats in the early twentieth century. The reverse is true.

Results of some early studies of fats and coronary thrombosis suggested that individual saturated fatty acids were likely to cause blood platelets to clump together and form clots (thromboses). But these studies were conducted in glass dishes, a method now known to give entirely wrong results.

For example, an in vitro (in glass) study from 1962 reported that the saturated fatty acid, stearic acid, found widely in animal fats, considerably shortened the time needed for a clot to form whereas unsaturated fatty acids had almost no such effect.[1] In the model used, other saturated fatty acids commonly found in animal fats also increased clot formation. But contradictory results from other studies meant that results taken together were inconclusive.

In 1996 a study looked at this whole vexed question by testing individual saturated fatty acids in real, live people.[2] It showed the exact opposite of what had been observed in the laboratory studies: the saturated fats suspected of increasing the risk of a blood clot actually reduced the risk of clotting.

Another worry about saturated fats, that they might contribute to heart disease by adversely affecting blood cholesterol sub-fractions (HDL and LDL), has also been shown to be unwarranted. A study, presented at the Canadian Institute of Food Science and Technology's conference in June 2001 by Margaret French, of Canada's Department of Agricultural, Food and Nutritional Science, found that 112g (4 ounces) of beef eaten twice daily raised neither total nor LDL cholesterol any more than diets that were primarily of chicken, beans and pulses.[3]

French also noted that saturated fats had benefits such as lowering stress hormone levels and improving blood flow by reducing peripheral vascular resistance.


1. Connor W. The acceleration of thrombus formation by certain fatty acids. J Clin Invest 1962: 41: 1199-205.
2. Tholstrup T, Andreasen K, Sanstrom B. Acute effect of high-fat meals rich in either stearic or myristic acid on hemostatic factors in healthy young men. Am J Clin Nutr 1996; 64: 168-76.
3. For further details, contact or see:

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