Butter, plant-based oils and death in US adults
What it found
In three large groups of US adults followed for up to 33 years, people who ate the most butter had a higher risk of dying than those who ate the least.
Those who ate the most plant-based oils had a lower risk.
What they found
Studies in people
Butter and total deaths
The highest butter intake was linked to a 15% higher risk of death from any cause compared to the lowest intake. This was after adjusting for other factors.
Plant oils and total deaths
The highest intake of total plant-based oils was linked to a 16% lower risk of death from any cause compared to the lowest intake. Canola, soybean, and olive oils each showed a link to lower total mortality.
Plant oils and cancer deaths
Every 10-g/d increase in plant-based oils was linked to an 11% lower risk of cancer death. Higher butter intake was linked to a 12% higher risk of cancer death.
Plant oils and heart deaths
Every 10-g/d increase in plant-based oils was linked to a 6% lower risk of death from cardiovascular disease.
Swapping butter for oils
Replacing 10 g/d of butter with the same amount of plant-based oils was linked to a 17% lower risk of death from any cause and a 17% lower risk of cancer death.
What the authors conclude
“Substituting butter with plant-based oils may confer substantial benefits for preventing premature deaths.”
Also in their conclusions
- They say higher intake of butter was associated with increased mortality, while higher plant-based oils intake was associated with lower mortality.
- They conclude that substituting butter with plant-based oils may confer substantial benefits for preventing premature deaths.
How it was done
The link between butter and plant-based oil intakes and death was unclear, with previous studies giving conflicting results. The authors say long-term dietary assessments were needed to clarify these links.
They followed 221 054 US adults from three large cohorts: the Nurses' Health Study, Nurses' Health Study II, and the Health Professionals Follow-up Study, from around 1990 to 2023. Everyone was free of cancer, heart disease, diabetes, or neurodegenerative disease at the start. Diet was checked with food questionnaires every 4 years.
What it can’t tell you
- We summarised it from the abstract only.
- This kind of study follows people over time and can show a link, but it cannot prove that butter or oils directly cause or prevent death.
- People who eat more butter may differ in other ways that affect health, and the study tried to adjust for these but cannot rule them out completely.
Who paid
- Funding
- Funded by NIDDK NIH HHS; NIA NIH HHS; NINR NIH HHS (from the PubMed record).
- Conflicts
- Conflict of Interest Disclosures: Dr Guasch-Ferré reported grants from the Novo Nordisk Foundation and the International Nut and Dried Fruit Council outside the submitted work. Dr Willett reported grants from the National Institutes of Health during the conduct of the study. Dr Stampfer reported grants from the National Institutes of Health during the conduct of the study. No other disclosures were reported.
- Authors work at
- Harvard T.H. Chan School of Public Health, Massachusetts; Brigham and Women's Hospital and Harvard Medical School, Massachusetts; Broad Institute of MIT and Harvard, Massachusetts
The paper
- Title
- Butter and Plant-Based Oils Intake and Mortality
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Zhang Y, Chadaideh KS, Li Y, et al (2025). Butter and Plant-Based Oils Intake and Mortality. JAMA internal medicine. doi:10.1001/jamainternmed.2025.0205Free full textPubMed 40048719DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error