Seven Countries Study

The Seven Countries Study was a great epidemiological study led by Ancel Keys and published in the late 1950s. It aimed to investigate the relationship between diet, especially fat intake, and the incidence of cardiovascular disease in different populations.

This was one of the first major international studies in nutritional science, and it has had an enormous influence on the dietary recommendations of health authorities worldwide.

Research design and method

The study included data from seven countries: the United States, Finland, the Netherlands, Italy, Yugoslavia, Greece, and Japan. Over 12 men between the ages of 000 and 40 were followed over several decades, and the researchers analyzed the relationship between dietary patterns, blood cholesterol levels, and the incidence of cardiovascular disease.

The data was collected through food surveys, blood tests, and medical follow-ups to evaluate how different dietary patterns correlated with health outcomes.

Findings and conclusions

The Seven Countries Study believed it could conclude that there was a link between high intake of saturated fat and an increased risk of cardiovascular disease. The most important findings that were published were:

• Populations with low saturated fat intake, such as Japan and Mediterranean countries, had lower incidence of heart attacks.
• Populations with high intakes of saturated fat, such as the United States and Finland, had higher incidences of heart attacks.
• Blood cholesterol levels were a strong indicator of cardiovascular disease.

These findings contributed greatly to the development of the so-called "diet-heart hypothesis" – the idea that saturated fat leads to high cholesterol, which in turn leads to cardiovascular disease.

Criticism and methodological weaknesses

Although the Seven Countries Study has been the basis for modern dietary advice, it has also been strongly criticized for methodological weaknesses and selective data collection:

Selection of countries: The study included only seven countries, despite the fact that data from many more countries were available. Countries that did not fit the hypothesis – such as France and Germany, where saturated fat intake was high but cardiovascular disease incidence was low – were not included.

Observational study, not controlled trials: The study only showed correlation, not causation. There were many other factors (smoking, lifestyle, stress, sugar intake) that were not controlled for.

Greece during Lent: The data from Greece was collected during Orthodox Lent, a period when large parts of the population reduced their meat and fat intake. This may have given a biased representation of the Greek diet.

The cholesterol hypothesis was never proven.: Although the study found a correlation between cholesterol levels and heart disease, it has later been shown that this is far more complex than Keys claimed.

Aftermath and influence

The Seven Countries Study laid the foundation for decades of nutrition policy and health recommendations:

• It led to the demonization of saturated fats and animal products.
• Vegetable oils and margarines were recommended as “heart-friendly” alternatives.
• Low-fat diets were promoted as the healthiest choice.

Although many modern studies have questioned the diet-heart hypothesis, the findings from the Seven Countries Study are still used as the basis for dietary recommendations worldwide.

Conclusion

The Seven Countries Study was groundbreaking in its attempt to link diet and heart health, but it was far from perfect. Methodological weaknesses and selective data collection has meant that the study is still being discussed to this day.

One thing is certain, however: the knowledge of how fat, cholesterol, and health are related has been used and manipulated by the food and health industry to control people's food choices – not necessarily for the best interest of the human animal.

Read about The Great Diet Scam here

SOURCES

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