Saturated fat and cardiovascular disease
Most medical, scientific, heart-health, governmental, and professional authorities agree that saturated fat is a risk factor for cardiovascular disease, including the World Health Organization, the Food and Nutrition Board of the National Academy of Medicine, the Academy of Nutrition and Dietetics, the Dietitians of Canada, the Association of UK Dietitians, the American Heart Association, the British Heart Foundation, the Heart and Stroke Foundation of Canada, the World Heart Federation, the British National Health Service, the United States Food and Drug Administration, and the European Food Safety Authority. All of these organizations recommend restricting consumption of saturated fats to reduce that risk.
There is moderate quality evidence that reducing the proportion of saturated fat in the diet, and replacing it with unsaturated fats or carbohydrates over a period of at least two years, leads to a reduction in the risk of cardiovascular disease.
History
Cholesterol and cardiovascular disease
The initial connection between arteriosclerosis and dietary cholesterol is attributed to the Russian pathologist Nikolay Anichkov, prior to World War I.Dutch physician Cornelis de Langen noted the correlation between nutritional cholesterol intake and incidence of gallstones in Javanese people in 1916. de Langen showed that the traditional Javanese diet, poor in cholesterol and other lipids, was associated with a low level of blood cholesterol and low incidence of cardiovascular disease, while the prevalence of CVD in Europeans living in Java on a Western diet was higher. Since de Langen published his results only in Dutch, his work remained unknown to most of the international scientific community until the 1940s and 1950s.
Saturated fat and cardiovascular disease
The hypothesis that saturated fat has a detrimental effect on human health gained prominence in the 1950s as a result of the work of Ancel Keys, a US nutritional scientist. At that time in the USA, the incidence of heart disease was rapidly increasing, for reasons that were not clear. Keys postulated a correlation between circulating cholesterol levels and cardiovascular disease, and initiated a study of Minnesota businessmen.Keys presented his diet-lipid-heart disease hypothesis at a 1955 expert meeting of the World Health Organization in Geneva. In response to criticism at the conference, he set out to conduct the years-long Seven Countries Study. Ancel Keys joined the nutrition committee of the American Heart Association and successfully promulgated his idea such that in 1961, with the result that the AHA became the first group anywhere in the world to advise cutting back on saturated fat to prevent heart disease. This historic recommendation was reported on the cover of Time Magazine in that same year.
Systematic reviews
Summary table of data
| Systematic reviews and meta-analyses of both prospective cohort data and randomised controlled trials. | Relationship between cardiovascular disease and saturated fatty acids |
| Zhu et al., 2019 | A meta-analysis of cohort studies found no association between dietary saturated fat intake and risk of cardiovascular diseases. Higher intake of trans fatty acids was associated with greater risk of cardiovascular diseases. |
| American Heart Association: Presidential Advisory on Dietary Fats and Cardiovascular Disease | "Randomized controlled trials that lowered intake of dietary saturated fat and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by about 30%, similar to the reduction achieved by statin treatment." All-cause mortality was not reduced across the 4 trials selected. |
| Hamley, 2017 | This review found no effect of saturated fats, when replaced by vegetable oils rich in polyunsaturated fatty acids, on total mortality or cardiovascular mortality. "Available evidence from adequately controlled randomised controlled trials suggest replacing SFA with mostly n-6 PUFA is unlikely to reduce CHD events, CHD mortality or total mortality. The suggestion of benefits reported in earlier meta-analyses is due to the inclusion of inadequately controlled trials. These findings have implications for current dietary recommendations." |
Review details
A 2017 systematic review focusing on adequately controlled randomized controlled trials concluded that replacing saturated fats with mostly n-6 polyunsaturated fats is unlikely to reduce coronary heart disease events, CHD mortality or total mortality. The 2017 review showed that inadequately controlled trials that were included in earlier meta-analyses explain the prior results.A 2017 systematic review by the American Heart Association recommended that decreasing saturated fat intake and increasing consumption of monounsaturated fats and polyunsaturated fats could lower risk of cardiovascular disease by about 30%.