If you think everything is better with butter, you might want to think again. A new study suggests that people who eat lots of butter have an increased risk of premature death.
The study included about 221,000 adults who were typically in their midfifties and had no history of major health issues such as heart disease, diabetes, cancer, or neurodegenerative diseases like Alzheimer’s or multiple sclerosis.
Over a follow-up period of up to more than three decades, participants completed dietary questionnaires every four years that included information on their consumption of butter, safflower oil, soybean oil, corn oil, canola oil, and olive oil.
People who ate the most butter were 15 percent more likely to die of all causes during the study period.
But plant-based oils appeared to have the opposite effect. People who ate the most plant-based oils were 16 percent less likely to die during the study.
Researchers controlled for confounding factors including age, body mass index (BMI), physical activity, smoking and alcohol consumption, and history of high blood pressure or high cholesterol.
Fat Type Makes a Difference in Early Death Risk
The different impact of butter and plant-based oils on longevity is likely due to differences in the types of fats they contain, says Yikyung Park, ScD, a professor at the Washington University School of Medicine in St. Louis, who wasn’t involved in the new study.
“The fat in butter is mostly saturated fat, which is considered unhealthy because it increases bad cholesterol in the blood, which is linked to a higher risk of heart disease,” Dr. Park says.
“But plant oils mostly contain unsaturated fat, which is the healthy type,” Park says. “Unsaturated fats can improve your blood lipid profile and help fight inflammation in the body.”
Just 1 Daily Tablespoon of Butter Was Harmful
It didn’t take a lot of butter to increase the risk of premature death, the study found. People who consumed the highest amount of butter ate about 13 to 14 grams (g) daily, or about 1 tablespoon (tbsp). There are typically 8 tbsp in a stick of butter. People with the lowest butter consumption took in, at most, about 0.2 g daily.
The negative impact of butter on longevity appeared tied to how much butter people put on their bread, the study found. The amount of butter people used for baking and frying food didn’t make a meaningful difference in the risk of premature death.
Canola, Soybean, and Olive Oil Were Tied to Lower Early Death Risk
People who ate the highest amount of plant-based oils (tied to the biggest longevity boost) consumed about 5 teaspoons (tsp) per day. Low consumption was about 1 tsp per day.
Three types of oil did the most to reduce the risk of premature death: canola, soybean, and olive. Corn oil and safflower oil, two seed oils, didn’t appear to significantly affect longevity, the study found.
Each additional 10 g (about 2 tsp) a day of plant-based oils was associated with an 11 percent lower risk of premature death from cancer and a 6 percent lower risk of fatalities from heart disease, the study also found.
In contrast, each additional 10 g of butter a day was tied to 12 percent higher risk of premature death from cancer, but didn’t appear to alter the risk of heart disease fatalities.
A Healthy Diet for Longevity
The study wasn’t designed to prove whether or how eating more butter might cause early deaths or how consuming more plant oils might prevent premature fatalities.
One limitation of the study is that it relied on people to accurately recall and report on how much butter and oil they consumed, leaving room for human error. Another is that most study participants were white healthcare workers, so the findings may not be generalizable to other groups.
Finally, it’s possible that other eating habits influenced the connections between longevity, butter, and plant-based oils.
“The lower mortality with plant-based oils is most likely related to people using these as part of a healthier diet,” says Penny M. Kris-Etherton, PhD, RD, an emeritus professor of nutritional sciences at Pennsylvania State University in University Park who wasn’t involved in the new study. “They would have a higher diet quality, which decreases the risk of cardiovascular disease and cancer.”
The health benefits of adding plant-based oils to your diet depend a lot on how you do it, Dr. Kris-Etherton says.
For example, consuming salad dressings with plant-based oils or using these oils to roast vegetables or sauté lean proteins like poultry or seafood will likely help you achieve the longevity benefits seen in the study, Kris-Etherton says.
By contrast, eating lots of ultra-processed foods like potato chips or sweets like cakes and cookies that contain plant-based oils is less likely to provide the same longevity benefits, she says.
Moderation is also key, even when it comes to healthier plant-based oils, Park says. You should aim to get no more than 20 to 35 percent of your daily calories from fats, including plant-based oils, Park says.
“While plant-based oils are a healthier choice than butter, eating too much of any oil can increase your calorie intake and potentially lead to weight gain,” Park says. “So, it’s important to use them in moderation.”
