American Heart Association study links plant-based oils to lower risk of premature death

Replacing butter with plant-based oils may significantly reduce the risk of premature death from all causes, cancer, and cardiovascular disease, according to new research presented at the American Heart Association’s Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2025. The study, which analyzed more than 33 years of dietary data from over 200,000 adults in the U.S., was simultaneously published in JAMA Internal Medicine.

The study found that individuals who consumed the highest amounts of butter had a 15% higher risk of death from all causes compared to those with the lowest intake. Additionally, each additional 10 grams of butter consumed per day—just under one tablespoon—was associated with a 12% increased risk of death from cancer.

“Our study found that higher butter intake was associated with increased deaths from all causes and cancer,” said lead author Yu Zhang, M.B.B.S., a graduate student at the Harvard T.H. Chan School of Public Health and a research assistant at Brigham and Women’s Hospital in Boston. “Meanwhile, higher intake of plant-based oils was associated with lower deaths from all causes, cancer, and cardiovascular disease.”

The analysis revealed that participants with the highest intake of plant-based oils—including olive, canola, soybean, safflower, and corn oils—had a 16% lower risk of premature death. Furthermore, increasing daily plant oil intake by 10 grams was associated with an 11% reduction in cancer mortality risk among participants who increased their intake of plant-based oils; and a higher intake of plant-based oils was associated with a 6% reduction in the risk of death from cardiovascular disease.

In a separate analysis, researchers estimated that replacing 10 grams of butter per day with an equal amount of plant-based oil resulted in a 17% reduction in overall mortality risk and a 17% reduction in cancer mortality risk.

“The findings suggest that replacing butter with plant-based oils, especially olive, soybean, and canola oils, may have a significant association with reducing the risk of premature death,” Zhang stated.

The research was based on three long-term studies: the Nurses’ Health Study, Health Professionals Follow-Up Study, and Nurses’ Health Study II. Participants were free of major chronic diseases at the time of enrolment. The study population included 221,054 individuals, with follow-up spanning from the early 1990s to 2023.

Dietary intake was assessed every four years using validated food frequency questionnaires. Participants self-reported their consumption of butter and plant-based oils, including their use in cooking, baking, and as spreads. Mortality outcomes were tracked using the National Death Index from the US Centers for Disease Control and Prevention.

The study aligns with existing dietary recommendations that encourage replacing saturated fats—predominantly found in animal-based foods like butter—with unsaturated fats from plant-based sources. The American Heart Association advises limiting saturated fat intake to less than 6% of total daily calories, which equates to about 13 grams per day for a standard 2,000-calorie diet.

“I think that this study’s central finding really continues to support dietary guidance on limiting sources of saturated fat,” commented Maya Vadiveloo, Ph.D., R.D., FAHA, an American Heart Association volunteer and chair of the Association’s Lifestyle Nutrition Committee, who was not involved in the study. “Replacing sources of saturated fat with plant-based unsaturated fats, such as canola oil, olive oil, and other liquid plant-based oils, remains an effective strategy.”

While the findings provide strong evidence supporting dietary shifts toward plant-based oils, the study had some limitations. The sample population consisted primarily of white health professionals, which may limit its generalizability to more diverse demographic and socioeconomic groups. Additionally, dietary intake data was self-reported, meaning there is potential for recall bias.

Despite these limitations, researchers emphasize that dietary patterns, rather than individual food choices, are key to improving health outcomes. “People don’t just eat saturated fat—they eat food that contains saturated fat,” Vadiveloo added. “Building a diet rich in vegetables, fruits, whole grains, nuts, and legumes while minimizing sources of saturated fats like processed red meats and butter can be an effective approach.”