Ancel Keys was a US scientist, who mainly worked and lived in Minnesota and managed to become a 100 years old (respect!). He reached early international fame by doing the Minnesota Starvation Study to aid the populations on the globe hit by famine after WW II. Later on, he did the Seven Countries Study, for which study he however had data from 20 nations/populations, but only used the seven, which seemed to support his hypothesis.
From Wikipedia: After observing in southern Italy the highest concentration of centenarians in the world, Keys hypothesized that a Mediterranean-style diet low in animal fat protected against heart disease and that a diet high in animal fats led to 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. As a result, in 1956 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. This resulted in the American government (George McGovern) recommending that people adopt a low-fat diet in order to prevent heart disease.
Keys had concluded that saturated fats as found in milk and meat have adverse effects, while unsaturated fats found in vegetable oils had beneficial effects. This message was obscured for a 20-year period starting around 1985, when all dietary fats were considered unhealthy. This was driven largely by the hypothesis that all dietary fats cause obesity and cancer.
Already in 2014 a meta-analysis examined the cardiovascular guidelines, that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats. The meta-analysis concluded that those guidelines were not "clearly" supported by the evidence. The meta-analysis was challenged and debated in many letters to the editor of Annals of Internal Medicine and elsewhere.
Old data- New conclusions
A team of Researchers, led by Chris Ramsden has reopened archived data sets investigating the relationships between linoic oils, lower cholesterol levels and heart risk. The results clearly fly in the face of current theories and asks whether "incomplete" publication has contributed to overestimation of benefits.
Saturated or unsaturated? That is the question.
The standard diet-heart hypothesis states that, for the sake of our heart, we should replace saturated fats with unsaturated fats, such as vegetable oils rich in linoleic acid. Linoleic acid "should" lower cholesterol levels and this should prevent buildup of plaque on artery walls.
This, therefore, prevents heart-related health issues and extends life. At least, that is the commonly held belief. Reopening of the data sets collected almost half a century ago, however severely casts doubts on this standard interpretation.
The current diet-heart theory
Initially, randomized controlled trials demonstrated a reduction in blood cholesterol when saturated fats were replaced by linoleic acid. Next, observational evidence showed that elevated cholesterol levels are linked to coronary heart disease events.
These two findings infer that increased intake of linoleic acid will reduce cholesterol and thus reduce heart risks. However, no randomized controlled trials have ever directly demonstrated that replacing saturated fats with linoleic acid reduces cardiac mortality.
The researchers, led by Christopher Ramsden from the National Institutes of Health and University of North Carolina, cracked the vaults of a study that directly measured this theory. The study, called the Minnesota Coronary Experiment (MCE), was conducted 45 years ago.
The study, conducted from 1968 to 1973, included 9,423 participants between the ages of 20 and 97, making it the largest trial of its kind. All participants were also residents of state mental hospitals and a nursing home in which all meals were prepared for them, making it one of the most rigorously detailed studies.
Many nutritional studies have the drawback of relying on self-reported consumption based on food questionnaires. Oftentimes people simply cannot remember what or how much they ate on any given day. Here, the meals of every person were carefully logged. On the average, each patient was followed for about 15 months (!). Participants were randomly assigned to one of two groups, receiving either:
A then-standard diet containing 18.5 percent saturated fat from animal fats such as milk, cheese, beef and shortening, and 5 percent unsaturated fat, based on total calories.
A diet in which 50 percent of the saturated fats were replaced with vegetable oil (a mainstay in today\rquote s processed foods) and corn oil margarine (total 9 percent saturated fat and 13 percent unsaturated fat)
After analyzing the data, Ramsden and his team found that vegetable oils lowered total cholesterol levels by an average of 14 percent after one year. However, this lower cholesterol did NOT result in improved health and longevity, which is the conventional belief.
Instead, the research showed that the lower the cholesterol, the higher the risk of dying. For every 30 point drop in total cholesterol there was a 22 percent increased chance of death. In the 65 and older category, those who received vegetable oil experienced roughly 15 percent more deaths compared to seniors in the saturated fat group.
Vegetable Oil Nearly Doubled Rates of Heart Attack
The vegetable oil also did not result in fewer cases of atherosclerosis or heart attacks.On the contrary, autopsies revealed both groups had similar levels of arterial plaque, but 41 percent of the vegetable oil group showed signs of at least one heart attack compared to just 22 percent of those in the saturated fat group. According to the authors:
Available evidence from randomized controlled trials shows that replacement of saturated fat in the diet with linoleic acid [vegetable oil] effectively lowers serum cholesterol but does not support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes.
Findings from the Minnesota Coronary Experiment add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.
Surely, there will be more "debunking" going on in future years on what is "good" for society. Folks like me, who passed the 65 years mark, however cannot wait for that to happen though and have to take our fate in our own hands and protect ourselves against faulty science. Anyway- the study publication in the BMJ can be found below under downloads and it is also no surprise that Ancel Keys was co-investigator of the orginal Minnesota Coronary Experiment- without being mentioned as one!
The slide on the right is from a 1,5 minute YouTube video, where the results from a study by the World Health Organization is provided by Dr. Malcolm Kendrick, indicating strongly that there is absolutely no positive correlation between cardiac deathrates and cholesterol levels. QED The video itself you find below..