SPOTLIGHT: In their zeal to fight heart disease, medical authorities have treated the public like guinea pigs.

BIG PICTURE: In the 1950s, the idea that fat in our food raises the amount of cholesterol in our blood, which in turn leads to heart disease, was “an obscure theory.” The website of the American Heart Association (AHA) tells us:

The link between dietary fat and cholesterol was made for the first time in 1956 by Dr. Ancel Keys. The American Heart Association quickly takes the lead in helping Americans change unhealthy, high-fat eating habits.

By January 1961, it had issued a “general statement” about diet, heart attacks, and stroke that gave the green light to unsaturated fats such as margarine and corn oil, while advising that coconut oil, whole milk, cream, butter, cheese, meat, and chocolate were bad for your heart. That same month, a Time magazine cover story described Keys as drinking reduced-fat milk and eating unbuttered toast. He urged Americans to consume lean meat and fewer eggs.

But here’s the problem. Scientific findings can’t be considered valid until they have been replicated. Other scientists must follow the same steps and arrive at similar results. Until research has been successfully replicated, we don’t know if it’s accurate. The editor-in-chief of a leading medical journal has recently acknowledged that half the scientific literature “may simply be untrue.” One of the reasons for this wretched state of affairs, he says, is that too much research involves “small sample sizes.”

In the 1950s, Keys’ work suffered from precisely this problem. A 1957 paper discussed cholesterol readings in 951 men from 21 different populations. The average size of each group, therefore, was a mere 45 individuals. On this basis, Keys made sweeping statements about vastly different communities around the world.

The AHA should have taken steps to properly replicate his findings. It should also have emphasized that Keys’ research focused on middle-aged men, since that’s who was at highest risk of heart disease. No one had investigated whether substituting industrially refined margarine for natural butter was healthy for rapidly growing children, young mothers, or the elderly.

To this day, it’s difficult to tell where the influence of Keys stops and where the AHA begins. Historical accounts document his talent for cultivating friends in high places as well as his brilliance – but they also reveal his single-mindedness, his arrogance, and his hostility toward alternative points-of-view.

TOP TAKEAWAY: The American Heart Association didn’t bother to replicate pivotal research before it told the public to change its behaviour. Nor did it care that advice formulated for one group was being cavalierly applied to the population at large. The result was an uncontrolled public health experiment.

LINKS:

The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet Nina Teicholz

• my other commentary on this book: When government makes you fat
• About that French Paradox

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