In kitchens around the world, few ingredients inspire as much loyalty—and controversy—as butter. Its rich flavor, comforting presence, and place in culinary history make it hard to resist. Yet, behind its golden glow lies an important and increasingly urgent question: how does butter stack up against plant-based oils when it comes to your long-term health?
A sweeping new study published in JAMA Internal Medicine offers compelling evidence that the fats we choose daily—whether for drizzling, spreading, or sautéing—could influence not just heart health, but our overall risk of early deathindex (2).
Let’s explore the findings and what they mean for your plate, your arteries, and your potential to live a longer, healthier life.
Fat Is Not Just Fat: The Nutritional Nuance
Nutritional science has come a long way from the era of blanket fat avoidance. We now understand that fats are a complex family, with some types essential for health and others associated with disease.
- Saturated fats, found abundantly in butter, have long been linked to increased LDL (bad) cholesterol and cardiovascular risk.
- Unsaturated fats, the stars of plant-based oils like olive and canola, help lower LDL cholesterol and reduce inflammation.
- Trans fats, often artificially produced, are so harmful they’ve been largely phased out in many countries.
This updated study moves beyond the traditional fat classifications. Instead, it zooms in on two real-world fat sources: butter and commonly used plant oils. These foods represent how most people actually consume fats—not in isolated chemical forms, but as complex culinary choices.
The Study: A 33-Year Look at Fats and Mortality
To investigate the long-term effects of butter and plant-based oil consumption, researchers drew data from three of the most extensive and respected ongoing studies:
- The Nurses’ Health Study
- The Nurses’ Health Study II
- The Health Professionals Follow-up Study
Altogether, this dataset included more than 221,000 U.S. adults, tracked over up to 33 years. Participants completed food frequency questionnaires every four years, allowing researchers to track patterns in dietary fat intake and correlate them with outcomes like total mortality, cancer, and cardiovascular deathsindex (2).
Key Findings: What the Numbers Reveal
1. Butter Consumption and Mortality Risk
Participants with the highest butter intake had a 15% increased risk of all-cause mortality compared to those who consumed the least. Interestingly, how the butter was used mattered:
- No association was found between mortality and butter used in cooking (like baking or frying).
- Adding butter directly to food or bread, however, was associated with a 4% increase in mortality for every additional 5g consumed dailyindex (2).
This distinction suggests that direct consumption of saturated fat-rich foods may have a more significant metabolic impact than small quantities incorporated into cooking.
2. Plant-Based Oils and Longevity
In contrast, people with the highest intake of plant-based oils saw a 16% reduction in total mortality. The benefits varied by oil type:
- Olive, canola, and soybean oils were linked with significantly lower risks of death.
- Corn and safflower oils, however, did not show meaningful associations. This may be due to low consumption levels in the study cohort or differences in nutrient contentindex (2).
3. Cause-Specific Mortality Insights
When broken down by specific causes of death:
- Butter intake was associated with an increased risk of cancer-related mortality, but not cardiovascular mortality.
- Plant-based oils were associated with lower risks of both cancer and cardiovascular disease, with a 6% reduction in cardiovascular mortality and an 11% reduction in cancer-related deaths per 10g daily increase in oil consumptionindex (2).
Understanding the Mechanisms
What might explain these divergent effects?
Butter’s Role in Cancer Risk
Butter’s high saturated fat content is known to promote inflammation within adipose (fat) tissue. Chronic inflammation, in turn, creates a fertile ground for cellular damage and cancer development. Saturated fats also influence hormone levels, potentially increasing the risk for hormone-sensitive cancers such as breast or prostate cancerindex (2).
Plant Oils and Protective Metabolites
On the flip side, plant oils—especially olive oil and canola oil—are rich in monounsaturated fats and polyphenols. These nutrients are linked to:
- Reduced oxidative stress
- Lower systemic inflammation
- Improved blood lipid profiles
- Enhanced insulin sensitivity
Together, these factors contribute to a biological environment that resists disease and supports longevity.
Small Swaps, Big Benefits
One of the study’s most empowering takeaways is that modest dietary changes can yield meaningful results.
A substitution analysis showed that replacing just 10g of butter per day with plant-based oils reduced:
- Total mortality by 17%
- Cancer-related mortality by 17%
- Cardiovascular mortality by 6% (though this was not statistically significant)index (2)
Put practically, this could be as simple as swapping out a few daily pats of butter with a tablespoon of olive oil on your vegetables, toast, or in salad dressings.
What About Cooking Oils?
Interestingly, the study found that using butter in cooking—especially baking or frying—did not have a significant association with mortality. Why?
It’s likely that cooking applications involve smaller quantities spread over large portions and mixed with other ingredients, diluting the effect. Nonetheless, frequent high-heat cooking with any oil, even plant-based, can lead to the production of oxidized lipids, which carry their own risks. Whenever possible, low-heat applications or raw uses (like dressings) are preferable for delicate oils like extra virgin olive oil.
The Type of Oil Matters
While the overarching trend favors plant oils, it’s worth digging into the differences among them:
- Olive oil: Rich in antioxidants and widely studied in Mediterranean populations, olive oil continues to show strong protective associations across all mortality categoriesindex (2).
- Canola oil: A good source of alpha-linolenic acid (an omega-3 fat), it has a favorable effect on blood cholesterol and inflammation.
- Soybean oil: Though sometimes criticized for its processing, it’s high in polyunsaturated fats and may lower LDL cholesterol and coronary heart disease riskindex (2).
- Corn and safflower oils: The study found no significant associations. These oils contain fewer omega-3s and may degrade under heat, potentially releasing harmful byproducts.
Reconciling Mixed Messages
Some readers might recall earlier studies that seemed to exonerate butter—or at least downplay its risks. So why does this research show a clearer signal?
A few reasons:
- Study scale and duration: With over 200,000 participants tracked over decades, this dataset is unusually robust.
- Adjustments for confounding factors: This study carefully adjusted for variables like smoking, physical activity, and overall diet quality.
- Direct comparisons and substitutions: Rather than examining fat types in isolation, the researchers analyzed real-life dietary choices and replacements, providing more actionable insights.
Making Informed Fat Choices for Longevity
The takeaway from this large and nuanced study is clear: our daily fat choices matter, and small, sustainable changes can have ripple effects on our health trajectory.
What to Limit:
- Regular use of butter as a spread or topping
- Large quantities of saturated fats from animal products
- Refined oils with low omega-3 content and unclear sourcing
What to Embrace:
- Extra virgin olive oil for raw applications and light cooking
- Canola and soybean oil in moderation, especially cold-pressed versions
- A variety of whole foods that contain natural unsaturated fats, like avocados, nuts, seeds, and fatty fish
Final Thoughts: A New Era of Nutritional Subtlety
In an age of oversimplified dietary advice—carbs good, carbs bad; fat good, fat bad—this study offers a refreshing, evidence-based perspective. Butter isn’t inherently evil, and olive oil isn’t a magic potion. But when the question becomes, “Which of these fats contributes more to your long-term well-being?” the answer is increasingly clear.
Butter may have its place in tradition and flavor. But when it comes to supporting a longer, healthier life, the smart bet lies in the quiet power of plant-based oils, used intentionally and mindfully.
A tablespoon here. A drizzle there. Over time, these gentle habits add up—protecting your heart, calming inflammation, and maybe even extending your stay in this beautiful, complex world.