For the past decades, butter has been implicated as a significant cause of heart disease.
However, studies provide mixed results and whether butter truly increases the risk of chronic disease is hotly debated.
A recent meta-analysis examined how eating butter affects heart disease, type 2 diabetes and mortality risk. Here is a detailed summary of the findings.
Butter is a dairy product made from cream. It is almost pure milk fat, which mainly consists of saturated fatty acids.
The role of butter in health and disease is uncertain and hotly debated. Several studies show that a high intake of saturated fat is linked with a poor blood lipid profile, which is a risk factor for heart disease.
Additionally, one controlled trial showed that a high intake of saturated palm oil, rich in palmitic acid, caused greater gains in belly fat and liver fat, compared to polyunsaturated fat (1).
However, the largest and most recent meta-analyses of observational studies suggest that reducing saturated fat itself has neutral effects on health, whereas replacing it with certain unsaturated fats may have benefits (2).
Additionally, growing evidence suggests that not all saturated fats are the same and demonizing saturated fats as a whole is an oversimplification.
Nevertheless, official dietary guidelines continue to recommend lower intakes of all saturated fat and higher intakes of non-hydrogenated unsaturated fat (3).
Studies suggest that butter is different from other sources of dairy fat. Specifically, the fat in butter is not enclosed in a milk fat globule membrane (MFGM).
Whether these effects translate into an elevated risk of hard endpoints, such as heart attacks, remains unclear.
This meta-analysis examined the association between butter intake and heart disease, diabetes and all-cause mortality or death.
This was a systematic review and meta-analysis of prospective observational studies and randomized controlled trials examining the association of butter consumption with heart disease, diabetes and mortality.
The researchers searched scientific databases for all relevant studies that fulfilled the exclusion criteria. When conducting the analysis, they followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines.
A total of 9 publications were selected, including a total of 636,151 participants. No randomized controlled trials with hard endpoints were found.
Bottom Line: This was a systematic review and meta-analysis of prospective observational studies investigating the association of butter with the risk of heart disease, diabetes and death.
Finding 1: Butter Was Weakly Linked With All-Cause Death
Two large observational studies assessing the links between butter consumption and all-cause mortality (death) were included in the meta-analysis. These studies included a total of 379,763 participants.
The analysis showed that the risk of death increased by 1% for each tablespoon (14 grams) of butter consumed daily.
Bottom Line: The researchers discovered that for each tablespoon of butter eaten, the risk of death from any cause increased by 1%.
Finding 2: Butter Reduced the Risk of Diabetes
The analysis included four studies examining the links between butter consumption and type 2 diabetes. They included a total of 201,628 participants.
Pooling the findings from these studies, the researchers discovered that a higher intake of butter was linked with a modest decrease in the risk of developing type 2 diabetes.
Specifically, the risk of type 2 diabetes decreased by 4% for each tablespoon (14 grams) eaten daily.
Bottom Line: The study showed that each tablespoon of butter eaten daily reduced the risk of type 2 diabetes by 4%.
Finding 3: Butter Was Not Linked With Heart Disease
Five of the included studies investigated the association of butter with heart disease.
When their results were combined, butter intake was not significantly linked with heart disease, including stroke and coronary heart disease.
Bottom Line: The meta-analysis showed that butter was not significantly associated with the risk of developing heart disease.
The main limitation of this meta-analysis was the observational design of the included studies. Observational studies cannot demonstrate causality.
Since high butter consumption is generally associated with unhealthy dietary patterns and lifestyle habits, the study might have overestimated the association of butter with mortality, and/or underestimated its links with type 2 diabetes.
Summary and Real-Life Application
This analysis suggests that butter is neutral when it comes to the risk of developing heart disease.
Additionally, it was associated with a lower risk of type 2 diabetes, but a slightly elevated risk of overall mortality. Since these findings were based on observational studies, they should be taken with a grain of salt.
It should be noted that the elevated mortality risk associated with butter is relatively small compared to many other foods, such as refined grains and sugar.
In conclusion, it seems there is no compelling reason to avoid butter. Moderate amounts should be fine. However, if you eat lots of it, it may be wise to replace some of it with oils that have proven health benefits, such as olive oil.