Saturated fat and cardiovascular disease controversy

Most medical, scientific, heart-health, governmental, and professional authorities agree that saturated fat is a significant 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. Most medical, scientific, heart-health, governmental, and professional authorities agree that saturated fat is a significant 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. However, some meta-analyses of clinical trials and cohort studies have provided evidence against the recommendation for reduced intake of saturated fat, including one critique by scientists and one by a trade association. 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 (CVD), 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. 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 (the first prospective study of CVD). 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 (AHA) 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 (and dietary cholesterol) to prevent heart disease. This historic recommendation was reported on the cover of Time Magazine in that same year. 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 (CHD) events, CHD mortality or total mortality. The 2017 review showed that inadequately controlled trials (e.g., failing to control for other lifestyle factors) 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%. A 2015 systematic review also found no association between saturated fat consumption and risk of heart disease, stroke, diabetes, or death. A 2015 systematic review of randomized control trials by the Cochrane Library found that reducing saturated fat intake resulted in a 17% reduction in cardiovascular events, and that replacing saturated fats with cis unsaturated fats in particular is beneficial. It concluded: 'Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats.'