• Posted March 7, 2025

Butter Is A Deadly Delight, Study Says

It’s a cook’s maxim that everything’s better with butter.

Except your health, a new study suggests.

People who eat loads of butter have a higher risk of premature death, while those who use mostly plant-based oils like canola or olive oil have a lower-than-average risk, researchers found.

What’s more, swapping butter out for plant-based oils like canola or olive oil causes a person's risk of premature death to drop dramatically, researchers reported in JAMA Internal Medicine.

Substituting 10 grams of butter a day -- less than a tablespoon -- with plant-based oils could lower by 17% a person’s risk of death from any reason and from cancer specifically, results show.

"What's surprising is the magnitude of the association that we found — we saw a 17% lower risk of death when we modeled swapping butter with plant-based oils in daily diet. That is a pretty huge effect on health," lead investigator Yu Zhang, a research assistant at Brigham and Women's Hospital in Boston, said in a news release.

The findings are based on diet and health data from more than 220,000 people followed for more than three decades as part of three long-term studies of health professionals. Every four years, participants answered questions about their diets.

Total butter intake included butter and margarine blends, spreadable butter and butter used for baking and frying at home.

Intake of plant-based oils was estimated based on people’s use of them in frying, sautéing, baking and dressing salads.

Results show that people who ate the most butter had a 15% higher risk of dying compared to those who ate the least.

In contrast, those who ate the most plant-based oils had a 16% lower risk of death than those who ate the least.

Further analysis showed that swapping even a small amount of butter each day for plant-based oils could lower risk of death.

"People might want to consider that a simple dietary swap -- replacing butter with soybean or olive oil -- can lead to significant long-term health benefits," senior researcher Dr. Daniel Wang, an assistant professor of nutrition at Brigham and Women's Hospital, said in a news release.

"From a public health perspective, this is a substantial number of deaths from cancer or from other chronic diseases that could be prevented,” he said.

Butter and plant-based oils contain different types of fatty acids, and those fatty acids act differently upon the body, researchers said in background notes.

Butter is rich in saturated fatty acids, which have been linked to higher cholesterol and hardening of the arteries. These types of fats also are associated with inflammation and altered hormone activity, which can increase cancer risk.

On the other hand, plant-based oils have more unsaturated fatty acids, which can lower cholesterol, help maintain cell and brain health, fight inflammation, and even help a person absorb certain vitamins.

It’s also likely, according to an accompanying editorial, that a person who’s a butter fiend makes many other diet decisions that undermine their health.

“Butter is often associated with unhealthier dietary patterns, while plant-based oils are more commonly linked to healthier patterns, such as the Mediterranean diet and plant-based diets,” an editorial co-written by Dr. Young-Moon Mark Park, an assistant professor of epidemiology with the University of Arkansas for Medical Sciences, said. “These diets are rich in nutrient-dense foods and healthy fats, which work synergistically to reduce the risks of chronic disease and premature death.”

The study was published March 6. Researchers are also presenting these findings at an American Heart Association meeting that concludes Sunday in New Orleans. 

More information

The Cleveland Clinic has more on the health benefits of unsaturated fats.

SOURCES: Mass General Brigham, news release, March 6, 2025; JAMA Internal Medicine, March 6, 2025