Replacing Butter With Plant Oils Tracked With Lower Death Rates

CATEGORY: EATING FOR HEART HEALTH

Swapping a small daily amount of butter for plant oils tracked with roughly 17% lower risk of dying during the study period, in a group of more than 220,000 adults followed for up to three decades. The oils were ordinary ones: olive, soybean, canola. People who ate the most butter had modestly higher death rates than those who ate the least, and the pattern ran the other way for plant oils.¹

Top Butter Eaters 15% Higher, Top Oil Eaters 16% Lower

People were compared by how much butter or plant oil they usually ate. The highest butter group ran about 15% higher total mortality, meaning death from any cause, than the lowest. The highest plant-oil group ran about 16% lower. Then the researchers modeled a swap: take a small daily amount of butter, roughly two teaspoons, and replace it with the same amount of plant oil. That swap was associated with about 17% lower total mortality and about 17% lower death from cancer.¹

221,054 Adults, Food Questionnaires Every Four Years

The finding pools three long-running American studies: the Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-up Study. Together they cover 221,054 adults tracked for as long as 33 years. Every four years participants filled in detailed food questionnaires. Deaths were identified through the National Death Index, with causes confirmed from medical records. There were 50,932 across the follow-up, including 12,241 from cancer and 11,240 from cardiovascular disease.¹ No one handed these people a fat to eat. The researchers watched what they already ate, which is why this shows an association and cannot prove that the fats themselves made the difference.¹ Because the question is who lived longer over decades, the length of follow-up and the repeated diet check-ins are the machinery of the result rather than background. Earlier studies had reached conflicting conclusions about butter, plant oil and death risk, which is what prompted this analysis.¹

Saturated Fat, LDL Cholesterol, and Where the Limits Sit

Butter is high in saturated fat, which tends to raise LDL cholesterol, the kind that builds up in artery walls. Plant oils are rich in unsaturated fats, generally linked to healthier cholesterol and lower inflammation. That difference is the leading explanation researchers offer, though one study cannot confirm a mechanism.¹ The observational caveat bites here. People who reach for plant oils may differ in other ways that affect health, and adjusting for many lifestyle factors is not the same as removing them. The links were also stronger for butter used as a spread or in cooking than for the smaller amounts that go into baking. A pooled analysis of nine long-running cohort studies found only a weak link between butter itself and dying: about 1% higher risk for each extra tablespoon a day.² Against that, the swap result puts most of the weight on what takes butter’s place.

Key Takeaways

• Over as long as 33 years, higher butter intake tracked with about 15% higher risk of death and higher plant-oil intake with about 16% lower risk; modeling a small daily swap of one for the other gave about 17% lower total and cancer mortality.
• The study watched what people ate rather than assigning it, so it shows associations and cannot establish cause.

References

1. Zhang Y, Chadaideh KS, Li Y, et al. Butter and Plant-Based Oils Intake and Mortality. JAMA Internal Medicine. 2025;185(5):549–560. link
2. Pimpin L, Wu JHY, Haskelberg H, et al. Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality. PLOS ONE. 2016;11(6):e0158118. link.