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Is butter back? That depends on your viewpoint.

It’s no longer considered obviously unhealthy to eat butter. But the question of butter’s impact on major health outcomes is still an open one, and one that this meta-analysis of nine studies and over 636,000 adults tried to answer.

Study under review: Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality


The diet-heart hypothesis originally put forth[1] by Dr. Ancel Keys in the late 1950s proposes that dietary saturated fat raises blood cholesterol levels and therefore increases the risk of cardiovascular disease. Despite some researchers arguing that there were significant flaws in the data Keys used to support his claims, the hypothesis persisted and the nation was soon on an anti-saturated fat kick still observable in today’s dietary guidelines for Americans.

However, a 2010 meta-analysis[2] of 21 studies and nearly 350,000 people stirred the pot when researchers concluded that saturated fat consumption was not associated with cardiovascular disease, heart disease, or stroke. Then, in 2014, another, larger review and meta-analysis was published that appeared to undo the previous 60-some years of belief around saturated fat. After reviewing 32 observational studies with over 500,000 participants, this study showed that consumption of saturated fat was not significantly related to heart disease. This article spurred media headlines in Time Magazine and The New York Times suggesting that butter was healthy and everyone can indulge once again – guilt free.

People listened. Consumption of butter is the highest it has been since the 1960s. But with so many types of saturated fat, many of which have different physiological effects, how can researchers be certain that the findings regarding a type of nutrient (saturated fat) apply to butter?

Even the type of food from which the fat is obtained may influence its health effects. Butter and other forms of dairy fat are a great example of this. In ERD #9, we discussed how the milk-fat globule membrane may modulate the effect that dairy fat has on blood lipids. In short, dairy fat that contains the milk-fat globule membrane, such as cheese and non-homogenized cream, appears to have a neutral or beneficial impact on cardiovascular disease risk factors, whereas dairy fat without it, such as butter, is more often shown to have a detrimental impact.

Numerous observational studies have documented disparate[3] effects of dairy fat on cardiovascular[4] disease[5] and type 2[6] diabetes[7]. Accordingly, the current study sought to evaluate the long-term association between butter consumption and major health endpoints, including all-cause mortality, cardiovascular disease, and type 2 diabetes.

With emerging research questioning the link between saturated fat consumption and cardiovascular disease, many people have begun to once again enjoy their butter. However, questions remain about its health impact. The current meta-analysis sought to determine the relationship of butter consumption with all-cause mortality, cardiovascular disease, and type 2 diabetes.

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