A study published in JAMA Internal Medicine, which followed over 220,000 participants for more than three decades, found that higher butter consumption was linked to an increased risk of premature all-cause mortality. In contrast, greater intake of plant-based oils was associated with a 17% reduced risk of early death from any cause.

The study objective was to investigate the impact of butter (butter added at the table and from cooking) and plant-based (such as safflower, soybean, corn, canola, and olive) oil consumption on total and cause-specific mortality rates in US adults. Data for the study was obtained from three large long-term US studies: the Nurses' Health Study (1990–2023), the Nurses' Health Study II (1991–2023), and the Health Professionals Follow-up Study (1990–2023). Participants who were free of cancer, cardiovascular disease (CVD), diabetes, and neurodegenerative diseases at baseline were included in the present analysis. Participants were categorized into quartiles based on their butter or plant-based oil intake.

A total of 50 932 deaths occurred over 33 years of follow-up; 12,241 were due to cancer and 11,240 were due to CVD.

Results showed that the risk of total mortality increased by 15% among those with the highest butter intake vis a vis those with the lowest intake. The hazard ratio (HR) was 1.15. Conversely, participants with the highest intake of plant-based oils had 16% reduced risk of total mortality (HR 0.84).

Higher intakes of canola, soybean, and olive oils were significantly associated with lower total mortality. The hazard ratios (HRs) per 5 g/day increase were 0.85 for canola oil, 0.94 for soybean oil, and 0.92 for olive oil.

An increase of every 10 g per day in total plant-based oil consumption was linked to an 11% lower risk of dying from cancer (HR: 0.89) and a 6% lower risk of death due to CVD (HR: 0.94). In contrast, Every 10 grams per day of butter intake was associated with an increased risk of mortality due to cancer (HR: 1.12).

When 10 g/day of total butter intake was replaced with an equivalent amount of plant-based oils, total mortality declined by 17% (HR 0.83). A similar reduction was noted for cancer mortality (HR 0.83) along with a 6% lower risk of dying from CVD.

The study suggests that the choice of dietary fat may play a significant role in long-term health outcomes. Higher intake of butter was associated with a heightened risk of mortality, whereas greater consumption of plant-based oils was linked to lower mortality. Hence, clinicians should encourage their patients to incorporate healthier plant-based oils, which are rich in unsaturated fats, in place of butter rich in saturated fats, as part of a balanced diet to improve overall metabolic and cardiovascular health.

The findings of this study align with the American Heart Association’s Life’s Essential 8, a set of simple, actionable steps to adopt a healthier lifestyle and reduce the risk of disease. These include: Eat better (include whole foods, fruits and vegetables, seeds, nuts), be more active, quit tobacco, manage body weight, get adequate good quality sleep, control cholesterol, manage blood sugar and BP. Additionally, effectively manage stress.

Reference

1.   Zhang Y, et al. Butter and plant-based oils intake and mortality. JAMA Intern Med. 2025 Mar 6. doi: 10.1001/jamainternmed.2025.0205.