Butter and Plant-Based Oils Intake and Mortality.

Zhang Y, Chadaideh KS, Li Y, Li Y, Gu X, Liu Y, Guasch-Ferré M, Rimm EB, Hu FB, Willett WC, Stampfer MJ, Wang DD

JAMA internal medicine · May 1, 2025

Importance: The relationship between butter and plant-based oil intakes and mortality remains unclear, with conflicting results from previous studies. Objective: To investigate associations of butter and plant-based oil intakes with risk of total and cause-specific mortality among US adults. Design, Setting, And Participants: This prospective population-based cohort study used data from 3 large cohorts: the Nurses' Health Study (1990-2023), the Nurses' Health Study II (1991-2023), and the Health Professionals Follow-up Study (1990-2023). Exposures: Primary exposures included intakes of butter (butter added at the table and from cooking) and plant-based oil (safflower, soybean, corn, canola, and olive oil). Diet was assessed by validated semiquantitative food frequency questionnaires every 4 years. Main Outcomes And Measures: Total mortality was the primary outcome, and mortality due to cancer and CVD were secondary outcomes. Results: During up to 33 years of follow-up among 221 054 adults, 50 932 deaths were documented, with 12 241 due to cancer and 11 240 due to CVD. After adjusting for potential confounders, the highest butter intake was associated with a 15% higher risk of total mortality compared to the lowest intake (hazard ratio [HR], 1.15; 95% CI, 1.08-1.22; P for trend < .001). In contrast, the highest intake of total plant-based oils compared to the lowest intake was associated with a 16% lower total mortality (HR, 0.84; 95% CI, 0.79-0.90; P for trend < .001). There was a statistically significant association between higher intakes of canola, soybean, and olive oils and lower total mortality, with HRs per 5-g/d increment of 0.85 (95% CI, 0.78-0.92), 0.94 (95% CI, 0.91-0.96), and 0.92 (95% CI, 0.91-0.94), respectively. Substituting 10-g/d intake of total butter with an equivalent amount of total plant-based oils was associated with an estimated 17% reduction in total mortality (HR, 0.83; 95% CI, 0.79-0.86; P < .001). Conclusions And Relevance: In this cohort study, higher intake of butter was associated with increased mortality, while higher plant-based oils intake was associated with lower mortality.

PMID: 40048719 · DOI: 10.1001/jamainternmed.2025.0205