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What Research Says About Saturated Fat

The hottest potato in dietary discussions is probably about saturated fat. There is almost fundamentalist fervor when opponents and advocates of saturated fat clash in various blogs, health magazines and news programs.

When as an outside observer you read these heated discussions, you wonder if World War Three is imminent, triggered by saturated fat. For that reason let’s step back and take a nuanced look at what the research has shown — and what it hasn’t shown.

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Can Saturated Fat Cause Heart Disease?

The American physician Ancel Keys was the first to seriously promote the hypothesis that saturated fat may cause cardiovascular disease. His study from 1953 has rightly been criticized, however, because it omitted important data that otherwise would have weakened the connections.1

But the idea that saturated fat was an important cause of cardiovascular disease took root and has dominated dietary advice for half a century. The connection between high blood lipids (cholesterol) and heart disease has been shown in many subsequent studies. But the link between saturated fat and blood lipids is actually not as strong as previously maintained.1

Fact Box

Common sources of different types of fat:

Saturated fat: dairy products

Monounsaturated fat: olive oil, canola oil, almonds and avocados

Polyunsaturated fat: fatty fish, seeds and walnuts

A study from 2006 with almost 50,000 women showed no difference in the risk for heart disease between those who ate low quantities of saturated fat and those who ate like the population in general.

Follow-up studies have not shown clear, damaging effects from saturated fat either, possibly with the exception of some added risk for stroke.

Nor have the studies shown that saturated fat protects against heart disease. So it is positively incorrect to turn these results to say that “saturated fat is beneficial,” which sometimes happens. The fact that something is not damaging does not mean of course that it is automatically healthy.1,2

Polyunsaturated Fat Has Been Shown to Be Beneficial

On the other hand, it has been shown that polyunsaturated fat in fish is beneficial. Studies with a total of 13,600 participants have shown that the risk of cardiovascular disease is reduced by 19% if saturated fat is replaced with polyunsaturated fat.1

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In contrast to what has been asserted in dietary recommendations for decades, the research today shows that the risk with saturated fat is not as great as was previously thought. The effects of reducing saturated fat are instead about what we replace them with.

If we replace it with mono- and polyunsaturated fat from fish and vegetables, we can probably get positive health effects. But if we replace it with fast carbohydrates it is more doubtful whether it will have any effect.1,3

Take Studies and Self-Proclaimed Experts with a Pinch of Salt

Just because your neighbor has “perfect test results” from a certain diet doesn’t mean that the same diet will give you better health. You should be very careful about generalizing based on individual cases.

At the same time the opposite applies: It’s hard to say what the best diet is for you as an individual, based on median test results from thousands of research subjects.

You simply have to make your own assessments – based on the knowledge available but also your own experience and situation – and see what suits you.

What sources of information affect your eating habits?


1. Måns Rosén. [In Swedish: Sanningen om mat och hälsa: vad säger forskningen?]

2. Nordic nutrition recommendations

3. Statens beredning för medicinsk utvärdering. [In Swedish: Mat vid diabetes]

More to come

We are about to launch the full English version of the Swedish medical university initiative, PriusHealth, providing daily thought-provoking questions to unlock how you relate to yourself, to others, the larger us, as the way to improve your health.

Available both as an open website and a full guided program, it will be launched summer 2017. If you would like us to keep you informed of its launch and thereby get free access to more content, then click here.

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