Research Highlights:
- According to an independent study analyzing 33 years of data for more than 200,000 adults in the U.S., people who consumed the highest amounts of butter had an increased risk of death from all causes and from cancer compared to those who consumed the lowest amounts of butter.
- Alternately, a higher intake of plant-based oils, especially olive, canola and soybean oils, was associated with a lower risk of premature death from all causes. The analysis also found that a higher intake of plant-based oils was associated with a lower risk of premature death from all causes, cancer and cardiovascular disease.
- Participants who replaced 10 gm (almost a tablespoon) of total butter intake each day with an equivalent amount of total plant-based oils had a 17% reduction in risk of death from all causes and a 17% reduction in risk of death from cancer.
- Note: The study featured in this news release is a research abstract presenting at the American Heart Association's Epidemiology, Prevention, Lifestyle and Metabolic Health Scientific Sessions 2025, and the full manuscript is simultaneously published in the American Medical Association's peer-reviewed journal JAMA Internal Medicine.
NEW ORLEANS, March 6, 2025 — Replacing approximately a tablespoon of the total butter intake each day with an equivalent amount of plant-based oils may reduce the estimated risk of premature death from any cause as well as from cancer, according to independent research presented at the American Heart Association's Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2025 and simultaneously published today in the peer-reviewed journal JAMA Internal Medicine. The meeting will be held in New Orleans, March 6-9, 2025, and offers the latest science on population-based health and wellness and implications for lifestyle.
The study analyzed more than 3 decades of data for more than 200,000 adults in the U.S. and suggests that "even a modest daily change from butter to plant-based oils may lead to significant long-term health benefits," the research authors noted. The findings also emphasize the importance of evaluating whole foods rather than isolated nutrients to provide a practical basis for dietary recommendations, the authors also noted.
"Our study found that higher butter intake was associated with increased deaths from all causes and cancer, while higher intake of plant-based oils was associated with lower deaths from all causes, cancer and cardiovascular disease," said lead study author Yu Zhang, M.B.B.S., a graduate student at Harvard T.H. Chan School of Public Health and a research assistant at Brigham and Women's Hospital, both in Boston.
Researchers analyzed health and dietary information from three large studies of adults who were free of major chronic diseases at enrollment. Participants' dietary intake was assessed every four years using validated, semi-quantitative food frequency questionnaires, and participants' deaths were tracked for up to 33 years using the CDC's National Death Index. Participants' consumption of butter, as well as their consumption of commonly used plant-based oils — safflower oil, soybean oil, corn oil, canola oil and olive oil — were examined.
The analysis found:
- Participants in the group with the highest daily butter intake had a 15% higher risk of all-cause death compared to those with the lowest butter intake. Each additional 10 grams per day of butter (just under one tablespoon) was associated with a 12% increased risk of death from cancer.
- Those with the highest daily intake of plant-based oils had a 16% lower total risk of premature death. Every additional 10 grams daily of plant-based oils was associated with an 11% reduction in the risk of death from cancer and a 6% reduction in the risk of death from cardiovascular disease.
- In a separate analysis, researchers estimate that replacing 10 grams a day of butter with an equal amount of plant-based oil was associated with a 17% reduction in all-cause death 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 in reducing the risk of premature death," Zhang said.
Study details, background and design:
- The three cohorts analyzed by the researchers were the Nurses' Health Study, the Health Professionals Follow-Up Study and the Nurses' Health Study II. Researchers selected 221,054 participants not diagnosed with any major chronic diseases (cardiovascular disease, diabetes, cancer, neurodegenerative diseases) at enrollment. Approximately 84% of participants self-identified as women and 16% self-identified as men; approximately 95% of total participants self-identified as non-Hispanic white adults.
- Baseline assessments began in 1990 for both the Nurses' Health Study and the Health Professionals Follow-Up Study and in 1991 for the Nurses' Health Study II. Follow-up for all participants spanned to 2023, for a total of up to 33 years of health data.
- Dietary intake information was collected every four years using validated semi-quantitative food frequency questionnaires.
- Participants' total butter intake was calculated by multiplying five grams per pat of butter by how frequently they reported consuming butter, based on their responses to three questionnaire items: butter as either butter or margarine blend, spreadable butter added to food and bread (excluding cooking), and butter used in baking and frying.
- Total plant-based oil intake was assessed for five types of oils: olive, corn, safflower, soybean and canola oil. The intake of subtypes of plant-based oils (corn, safflower, soybean, canola, olive) was estimated based on the reported oil brand and type of fat used for various cooking methods, including frying, sautéing, baking and as salad dressing. All food composition data for calculating oil intake was updated every four years.
- Information about participants' demographics, lifestyle behaviors and medical history was obtained through patient questionnaires every other year.
- The total 50,932 participant deaths were tracked using the National Death Index from the U.S. Centers for Disease Control and Prevention and supplemented by medical records.
A limitation of the analysis is that participants in the studies examined included health care professionals who were primarily white women, so the results may not apply to the U.S. population as a whole, to men or to people with diverse economic, racial or ethnic backgrounds. In addition, the dietary information including consumption of butter and plant-based oils was self-reported via patient questionnaires, which may have led to errors including recall bias when participants do not remember or misremember previous events.
Saturated fats occur naturally in many foods and most come from animal sources, including meat and dairy products, including beef, lamb, pork, poultry, beef tallow, butter and cheese, as well as from tropical fruits such as coconuts. The American Heart Association's dietary guidance recommends limiting saturated fat intake (to less than 6% of total calories consumed each day) and replacing it with polyunsaturated and monounsaturated fats. For an adult consuming about 2,000 calories a day, that measures out to no more than 120 calories, or 13 grams, of saturated fat, which is a little less than one tablespoon of butter per day. The Association's 2021 Dietary Guidance to Improve Cardiovascular Health emphasizes the importance of dietary patterns beyond individual foods or nutrients. Optimal patterns would be high in fruits and vegetables, whole grain foods, healthy sources of protein, such as fish and seafood, legumes and nuts, poultry and other lean meats, and liquid plant oils, and minimizing consuming processed foods, foods and beverages high in sugar, and foods high in salt.
"I think that this study's central finding really continues to support dietary guidance on limiting sources of saturated fat and, particularly, replacing those sources of saturated fat with plant-based sources of unsaturated fat, such as canola oil, olive oil and other liquid plant-based oils," said Maya Vadiveloo, Ph.D., R.D., FAHA, an American Heart Association volunteer and chair of the Association's Lifestyle Nutrition Committee, and she was not involved in Zhang et al.'s study. Vadiveloo is also an associate professor of nutrition and health sciences in the department of nutrition and food sciences at the University of Rhode Island.
"What we still consistently see in this analysis is that higher saturated fat intake, particularly when it replaces unsaturated fat intake or makes that ratio imbalanced, promotes the synthesis of less healthy cholesterol profiles, which can lead to atherosclerosis," she said. "Sometimes when we talk about saturated fat, like butter, we forget that people don't eat saturated fat, they eat food that contains saturated fat. So, in addition to making substitutions for plant-based oils, one way to reduce saturated fat intake is by building a dietary pattern focused on eating vegetables, fruits, whole grains, nuts and legumes, and only occasionally including sources of saturated fats like processed red meats."
Co-authors and their disclosures are listed in the abstract. Funding sources are noted in the simultaneous publication.
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