Minnesota Coronary Experiment

The Minnesota Coronary Experiment is a study that is a striking example of how important scientific findings were withheld, and how this serious act helped determine dietary advice, and the entire public health narrative, for decades to this day.

The Minnesota Coronary Experiment was conducted between 1968 and 1973, promoted as one of the most thorough tests of diet-heart-hypothesis/diet-heart-hypothesis.

This hypothesis, created by the father of fat phobia Ancel Keys, claims that saturated fat in the diet increases cholesterol levels, which in turn leads to heart disease.

This study was led by Dr. Ivan Frantz and financed by US National Institutes of Health (NIH).

The aim was to investigate whether replacing saturated fat with polyunsaturated fat (specifically linoleic acid from vegetable oils) could reduce the risk of heart disease.

The study participants were patients in nursing homes and psychiatric institutions, which gave the researchers completely controlled conditions to study the effects of diet.

Participants were randomly divided into two groups:

The control group, who ate a typical old-fashioned American diet, which tended to be high in saturated fat from meat, butter, and tallow.

The intervention group received a diet rich in polyunsaturated fat from corn oil, instead of saturated fat.

The following major discoveries were kept secret for 40 years (!)

Although the study was specifically designed to confirm The diet-heart hypothesis, the results were unexpected. The intervention group that ate polyunsaturated fats actually experienced a reduction in serum cholesterol. However, the problem was this:

No reduction in mortality: Despite the cholesterol reduction, there was no corresponding reduction in deaths caused by heart disease, or total mortality.

Increased mortality: Patients who had greatest reduction in cholesterol on the contrary, had a increased risk of death, which should have raised questions about the safety and effectiveness of such dietary changes even then.

Despite the study; we were massively warned against saturated fat, and the phrase "Hot fat down a cold drain pipe" began to circulate.

The slogan was and is often used as a metaphor to explain how saturated fats, such as those from butter, tallow, or animal fat, behave in the blood vessels, compared to a pipeline. It has been used to create a mental image of saturated fats “hardening” in the blood vessels in the same way that grease can harden and block a drain pipe when hot grease meets cold water. Generations have been brainwashed with this scaremongering.

However, these findings challenged the prevailing belief in the 1970s that cholesterol and saturated fat were the main causes of heart disease, so the findings were hidden in a basement.

Why was it hidden?

The results were not published at the time, probably because they contradicted the dominant beliefs about cholesterol and saturated fat. This is actually considered a kind of scientific fraud, because the custom is to publish all findings – even when they say the opposite of our hypothesis.

The diet-heart hypothesis had gained wide acceptance ever since Ancel Keys invented it, and had already influenced public health guidelines, food industry practices, medical advice, and government investments and policy guidance.

So why this corruption, as one must call it?

• Confirmation bias: The researchers may of course have had difficulty accepting results that contradicted established beliefs. After all, results have to be published, so it is unlikely that they came up with this on their own.
  
• Industrial influence: The study was conducted at a time when vegetable oil producers had become very interested in promoting polyunsaturated fats as a healthy alternative. Throughout the century, the United States invested heavily in promoting production and use, and subsidies were loose.
  
• Career concerns: Publishing findings that undermined the prevailing narrative/story agreed upon, and the desirable narrative based on Ancel Key's hypothesis, could have jeopardized the researchers' reputations and careers, and was strictly speaking career suicide. To argue against this, and believe that one would be able to obtain grants for new studies – and thus a continued career – was and is unlikely.

Rediscovery and reanalysis

In 2016, discovered Dr. Christopher E. Ramsden, a researcher at the US National Institutes of Health, the missing data from MCE and published a reanalysis in The BMJRamsden specializes in investigating forgotten or mistranslated dietary studies.

The reanalysis confirmed the original findings and reignited the debate over the validity of the diet-heart hypothesis. The study showed that while dietary changes could lower cholesterol, they did not reduce the risk of death—and could actually increase it. This directly challenged decades of dietary recommendations.

Importance

The reanalysis of MCE has significant implications for nutritional science and public health:

1. Criticism of the lipid hypothesis: The findings suggest that the relationship between dietary fat, cholesterol and heart disease is far more complex than previously thought.
2. The role of polyunsaturated fats: Although promoted as heart-healthy, excessive use of linoleic acid-rich vegetable oils may be less beneficial – or potentially harmful – than thought.
3. Skepticism about dietary recommendations: The story raises questions about how public health recommendations are shaped, and what role industry and bias play in the scientific process.

A broader context

MCE is not the only example of hidden or underreported studies that challenge the diet-heart hypothesis.

Sydney Diet Heart Study, conducted in the 1960s and reanalyzed in 2013, found similar results: Replacing saturated fat with polyunsaturated fat lowered cholesterol but increased mortality.

Taken together, these findings demonstrate the need for a more nuanced understanding of fat, cholesterol, and heart health – and a reassessment of decades of dietary advice.

SOURCES

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