Does Saturated Fat Cause Heart Disease?

Posted on November 27th 2017 (almost 2 years)

Recent studies challenge the idea that saturated fat is to blame

Heart disease – a catch-all phrase for a variety of conditions that affect the heart’s structure and function – is the leading cause of death in the United States and responsible for a third of all deaths worldwide. For nearly a century much of the blame for the prevalence of heart disease lay with saturated fat, a type of fat commonly found in meats, such as beef, pork, and lamb, and in whole fat dairy products, such as cheese, butter, or cream. But recent scientific studies have challenged that idea, raising the question: Does saturated fat cause heart disease?

Data from observational studies cloud the issue

Much of the confusion surrounding the saturated fat/heart disease debate stems from the types of studies from which the conclusions were drawn. Although the findings of a large meta-analysis published in the journal Annals of Internal Medicine indicated that there was no evidence to support the notion that consumption of saturated fat increased the risk of heart disease, the studies on which their conclusions were based were primarily observational. These types of studies can show an association, but not causation. It’s important, then, to look at findings from studies that get more to the heart of the problem – specifically, randomized controlled trials, or RCTs.

A role for inflammation

At first glance, however, the data from RCTs seem to be inconsistent. But when we consider one unifying characteristic exhibited by the subjects of these studies – inflammation – it becomes obvious that there’s more to this debate. High systemic inflammation underlies processes fundamental to nearly all diseases of aging and even cancer, which is a disease of aging. This elephant in the room can’t be ignored when answering the question about diet and heart disease.

Refined sugar intake matters, too

A diet high in saturated fat sets us up for a litany of ills related to fat metabolism. But it’s only in the setting of a diet high in refined sugar that these bad things happen. In particular, when we eat saturated fat, our large, buoyant LDL increases – step number one. By itself (the randomized controlled trials seem to suggest) this first step is not enough. Only when we convert that large buoyant LDL into small, dense LDL – step number two, most likely due to consuming refined sugars and, in doing so, increasing our systemic inflammation. Then we have a problem. Saturated fat might be the smoking gun, but refined sugar is surely the trigger.

Complicating factors and a place for moderation

To say that dietary intake of refined sugar is to blame for heart disease is tempting. But the reality is that the way our bodies respond to food is also complicated by our genetics, microbiome, and lifestyle factors. Until scientists learn more about the role these different factors play, moderating saturated fat consumption and boosting polyunsaturated and monounsaturated fat consumption seems prudent.

In this episode, Rhonda digs deeper into the links between diet and heart disease and suggests ways to reduce individual risk.


Interested in learning more about your raw genetic data you got from a provider like 23andMe? The genes mentioned in this podcast can be found in the report at foundmyfitness.com/genetics.

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