Skipping Butter May Lower Mortality Risk by 17%

Seed oils have been at the center of controversy for some time now. Some social media influencers have been on a rampage to disparage seed oils—including canola oil, peanut oil, corn oil, soybean oil and safflower oil—claiming that they cause inflammation. 

Previous studies have suggested those seed oil fears are way overblown. Still, some cautious cooks and consumers are reaching for fats made with animal products, like butter or beef tallow, rather than opting for neutral oils. To clear up some of the seed oil controversy—and find out more about how eating butter can affect your health—researchers at Brigham and Women’s Hospital and Harvard Medical School dug into the data.

The research team conducted a large investigation on the mortality rates of people who eat more butter compared to those who eat more plant-based oils, including seed oils. They published their findings today in JAMA Internal Medicine. Here’s what they found. 

How Was This Study Conducted?

Researchers drew from three long-term U.S. studies: the Nurses’ Health Study (NHS), which ran from 1990 to 2023; the Nurses’ Health Study II (NHS II), which ran from 1991 to 2023; and the Health Professionals Follow-up Study (HPFS), which ran from 1990 to 2023. 

There were more than 220,000 men and women chosen for the study at hand, which included 33 years of follow-up. The average ages at baseline were 56 (for NHS and HPFS) and 36 (for NHS II). All of the participants were free of cancer, cardiovascular disease, diabetes and neurodegenerative disease at baseline.

Typical demographic information was collected, including race and ethnicity, alcohol intake, smoking status, medical history, family history, body mass index and physical activity levels. Participants completed dietary assessments covering more than 130 food items when the study began, then every four years afterwards.

Researchers calculated average intakes of butter and plant-based oil based on the dietary assessments that participants filled out. Then the team sorted participants into four groups according to their intake of butter and plant-based oils. 

Butter intake included butter used in baking and frying, as well as butter added to food or bread. Plant-based oils included in the assessment were corn oil, safflower oil, canola oil, soybean oil and olive oil. All but olive oil are considered seed oils.

What Did This Study Find?

Researchers ran several statistical analyses, including adjusting for potential confounders. They also adjusted for white bread and glycemic load, since these could impact the results. 

The researchers were looking for associations between butter intake, oil intake and early death—or early mortality—from anything, as well as dying from cancer and CVD. Here are a few of their findings:

• Every 10 grams per day of total plant-based oil intake was associated with an 11% lower risk of dying from cancer and a 6% lower risk of dying from CVD.
• Every 10 grams per day of butter intake was associated with a 12% increased risk of dying from cancer. There was no statistically significant connection to CVD.
• Every 5 grams per day of olive oil was associated with a 4% lower risk of dying from cancer and a 3% lower risk of dying from CVD.
• Every 5 grams per day of canola oil and soybean oil was associated with 19% and 6% lower risk of dying from cancer, respectively.
• Replacing 10 grams per day of total butter intake with an equivalent amount of total plant-based oil was associated with an estimated 17% reduction in total mortality (dying from anything), a 17% reduction in dying from cancer and a 6% lower risk of dying from CVD.

In simpler terms: higher butter intake was associated with an increased risk of early death from anything and an increased risk of dying from cancer. 

Higher intakes of plant-based oils were associated with a lower risk of early death from anything and dying from cancer and CVD. These associations were consistent for olive oil, canola oil and soybean oil but not for corn oil and safflower oils. Researchers note that these last two oils were not used as often in this population, which may have influenced the results.

Substituting butter with an equal amount of plant-based oils was associated with a 17% lower risk of early death from anything and from cancer.

How Does This Apply to Real Life?

Interestingly, butter was related to a higher risk of dying from cancer but not from CVD. Researchers believe that the high saturated fat content in butter can trigger adipose (fat) tissue inflammation, a key pathological pathway in the development of various cancers. They add that studies have shown that the saturated fats we eat can alter hormonal activity, influencing hormone-sensitive cancers like breast and prostate cancer.

While this study only looked at butter and did not consider other types of dairy products, there is evidence that full-fat dairy and saturated fat in general, when eaten in moderation, may not have much impact—positive or negative—on heart disease risk.

While scientists disagree on the exact ratio of saturated fats to unsaturated fats in the ideal diet, this study suggests that you can reduce your risk of early death and dying from cancer by replacing your butter with oil. And according to the 2020-2025 U.S. Dietary Guidelines for Americans, replacing saturated fat with polyunsaturated fats like corn, canola, soybean or sunflower may help lower the risk of heart-related events and death related to cardiovascular disease. 

But this isn’t an all-or-nothing thing. You’ll see that we use butter in some of our recipes, like our Buttermilk Mashed Potatoes with White Pepper and Brownie Cookies. It’s important to remember that nutrition isn’t all about nutrients. You’re supposed to enjoy what you’re eating, too. 

Our recommendation: Eat mostly unsaturated fats, but feel free to sprinkle in some healthy foods higher in saturated fat, like whole-milk dairy, eggs, coconut oil and even butter, now and then. 

The Bottom Line

This study suggests that replacing butter with plant-based oils—including olive oil, canola oil and soybean oil—may reduce your risk of early death and dying from cancer. You may also reduce your risk of dying from cardiovascular disease (CVD) or, as other studies have suggested, developing CVD to begin with. 

We recommend eating mostly unsaturated plant oils, but you should include some saturated fat from foods like dairy, eggs, coconut oil and butter occasionally. After all, there’s room in a healthy eating pattern for anything in moderation, and that includes butter. Aim to eat a varied diet that includes whole grains, lean proteins, fruit, veggies, nuts, seeds, fish and dairy. And engage in health habits, like moving your body more often, managing your stressors, getting plenty of quality sleep and spending time with loved ones. It all works together to reduce your overall disease risk and help you live a high-quality life.