Butter, Plant Based Oils And Risk Of Mortality

A number of popular fad diets consider butter a healthy source of fat and place no limitations on its consumption. Followers of these diets are even known to put butter in their coffee instead of milk. As a nutrition researcher, seeing this is both fascinating and sad. It is fascinating for me to see how far these fad diets deviate from what the research literature has taught us in the last several decades. It is sad because I know these people are hurting their health.  

Decades of convincing research has shown that butter and other saturated fats have a negative impact on LDL cholesterol and inflammation. This can increase risk of cardiovascular disease and even cancer. A recent study was published in JAMA Internal Medicine that looked at the long-term risk of death for those that consume a lot of butter compared to those that choose plant-based oils more frequently.

The Study 

Harvard University conducted this study with a combined cohort including The Nurses’ Health Study, The Nurses’ Health Study II and The Health Professional Follow-up Study (Reference 1). The Study included over 221,000 subjects who were followed for up to 33 years. The results were compelling:

-Subjects consuming the most butter had a 15% higher risk of dying from any cause when compared to subjects who consumed the least.

-Subjects consuming the most plant-based oils had a 16% lower risk of dying from any cause when compared to subjects who consumed the least. 

-Substituting 10 grams of butter each day with plant oils reduced mortality by 17%. 

Conclusions And Recommendations

So, why is butter harmful? It is high in saturated fat. This has a negative impact on LDL cholesterol and can increase risk of heart disease and stroke. Saturated fat also increases inflammation, which is an important pathway to cancer. There is also evidence that saturated fat increases hormonal activity, which can have a negative influence on hormone sensitive cancers like breast and prostate cancer.

Why are plant oils beneficial? For the opposite reasons. They decrease LDL cholesterol and inflammation.

The take home message is pretty simple: Strictly limit butter.  Use plant oils such as olive oil and canola oil instead. If a meal or food calls for butter, you can instead use a plant based oil spread like Olivio or Smart Balance. These taste a lot like butter and are way healthier for you.

References

1) Zhang Y, et al. Butter and plant based oils intake and mortality. JAMA Intern Medicine doi:10.1001/jamainternmed.2025.0205