Ancel Keys and the Effect of Saturated Fats on Our Health

Ancel Keys

Ancel Keys (1904-2004)

On January 26, 1904, American nutritionist and epidemiologist Ancel Keys was born. Keys studied the influence of diet on health. In particular, he hypothesized that saturated fat in the diet is unhealthy and should be avoided. He also was the first to identify the role of saturated fats in causing heart disease.

Early Years

Ancel Keys was born in Colorado Springs in 1904 to Benjamin Pious Keys (1883-1961) and Carolyn Emma Chaney (1885-1960), the sister of US-american stage and film actor Lon Chaney. In 1906 they moved to San Francisco before the 1906 San Francisco earthquake struck, after which the family relocated to Berkeley where he grew up. After finishing his secondary education, Ancel Keys was admitted to the University of California at Berkeley in 1922 to study chemistry, but took time off to work as an oiler aboard the S.S. President Wilson (1st) travelling to China. Keys later graduated in 1925 with a B.A. in economics and political science and in 1928 with an M.Sc. in zoology. He continued his studies at Scripps Institution of Oceanography  in La Jolla on a fellowship and earned his Ph.D. in oceanography and biology from UC Berkeley in 1930. With another fellowship, Ancel Keys traveled to Kopenhagen studying under August Krogh at the Zoophysiological Laboratory. Upon his return to the United States, Keys taught at Harvard and later returned to Cambridge where he earned a second Ph.D. in physiology in 1936.

Research on Sports Physiology

When Keys returned to the United States in 1933, he began researching sports physiology at the Fatigue Laboratory at Harvard. His first project was a study of the effects of life at altitude on blood oxygenation, as he believed this could be of practical benefit to copper miners in Chile. He travelled with a small group of people to the Chilean Andes and gradually acclimatized them to an altitude of 22,000 feet.

The Starvation Experiment

In 1939, he was asked by the United States Department of War to develop and test a food ration for paratroopers. At that time, he was head of the Laboratory of Physiological Hygiene at the University of Minnesota, where he also conducted his studies on human nutrition, which were to extend over the next decades. With millions of people suffering from food insecurity during the Second World War, Keys began a research project called the Minnesota Starvation Experiment. He researched 32 people, focusing on the physical and mental effects of starvation on the volunteers for six months, and then studied the physical and mental effects of different refeeding protocols on them for three months. The men involved were fed only on root vegetables, brown bread and simple starchy foods for three months, were subjected to semi-starvation, targeted malnutrition, while they had to walk an average of 22 miles (35 km) per week. In the course of the experiment, most participants lost about 25% of their weight and many suffered from anemia, fatigue, apathy, extreme weakness, irritability, neurological deficits and edema of the lower extremities. Even though the war finished before the results of the studies could be published, Keys completed a publication of his two-volume 1385-page Biology of Human Starvation, which still today in the beginning of the 21st century is regarded as decisive.

Research on Saturated Fats

In the meantime, Keys’ interest in diet and cardio-vascular disease (CVD) was triggered and Keys began to postulate a correlation between cholesterol levels and CVD and initiated a study of Minnesota businessmen. In 1951 Keys and his family took a sabbatical to Oxford. In this context, an Italian colleague claimed that heart disease would not occur in Italy, to which Keys initially reacted sceptically and set up a laboratory in Naples with his wife Margaret. Here he soon verified the low incidence of heart disease among Neapolitans and found that they had very low serum cholesterol levels. Keys hypothesized that a Mediterranean-style diet low in animal fat protected against heart disease. Keys and his wife then travelled to several European and African countries to measure the cholesterol levels of the population: Gradually, a pattern emerged suggesting that a diet rich in saturated fats increases serum cholesterol levels, which Keys regarded as a major cause of coronary heart disease. The results of what later became known as the Seven Countries Study appeared to show that serum cholesterol was strongly related to coronary heart disease mortality both at the population and at the individual level. Then, in the 1950s representatives of the American Heart Association appeared on television to inform people that a diet which included large amounts of butter, lard, eggs, and beef would lead to coronary heart disease.

A Critical View

However, the results of the study are viewed very critically. Although he had collected data from 22 countries, he limited his publication to seven of these countries. If all countries are included in the comparison, there is no positive correlation between the proportion of animal fats in the diet and the incidence of heart disease. The raw data of the study, which were kept under lock and key for a long time, even suggest an exact reverse correlation. The study is therefore now regarded as a large-scale fraud.[6] The increased incidence of heart disease in the 20th century in the western world is today mainly explained by other factors, such as increased sugar consumption.

Further Achievements

From further studies Ancel Keys concluded that saturated fats as found in milk and meat have adverse effects, while unsaturated fats found in vegetable oils had beneficial effects. Keys developed the Keys equation, which predicts the effect of saturated and polyunsaturated fatty acids in the diet on serum cholesterol levels. Keys found that saturated fats increase total and LDL cholesterol twice as much as polyunsaturated fats lower them.  In an article published in 1972, Keys coined the term body mass index (BMI) after the corresponding calculations had already been carried out by Adolphe Quetelet around 1832; Keys, however, assumed that the index should be applied to entire populations as a statistical means. Ancel Keys died on November 20, 2004, two months before his 101st birthday.

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