Butter, LDL, and the Myth of Harmless Plaque

Why High Cholesterol Isn’t Just a Number—and What the Latest Science Says About Oils, Fats, and Your Risk of Death
By Dr. Terry Simpson, MD – The Culinary Medicine Doc

We’ve all heard the story: butter’s back, LDL doesn’t matter, and as long as you’re low-carb, your heart is safe.

But what if I told you that the science—real, peer-reviewed science—tells a different story?
In this post, I’ll walk you through three powerful studies that dismantle the myth of “harmless” LDL and show why swapping butter for plant-based oils could literally save your life.

1. LDL and ApoB: The True Origins of Arterial Plaque

Atherosclerosis—the buildup of plaque inside arteries—often starts silently. But over time, it becomes the leading cause of heart attacks, strokes, and cardiovascular disease.

A key study from the Journal of the American College of Cardiology found that the primary trigger for plaque formation is not “existing plaque” as some influencers claim—but rather, LDL cholesterol and ApoB-containing lipoproteins that penetrate the arterial wall and kick off the inflammatory cascade that builds plaque [1].

Once inside, these particles don’t just hang out—they lead to plaque progression and destabilization, which is what causes heart attacks. No LDL, no plaque. It’s that simple.

2. High LDL, Worse Plaque—Even on Keto

A 2025 study published in JACC: Advances examined people on carbohydrate-restricted diets—many of whom had very high LDL cholesterol levels [2].

While some hoped the data would vindicate high LDL in the context of keto, that’s not what happened. The study found that the higher the LDL, the worse the atherosclerotic plaque—regardless of dietary pattern.

Bottom line: High LDL is still atherogenic, even if you’re “metabolically healthy.” That six-pack doesn’t protect your arteries.

3. Butter Increases Mortality. Plant-Based Oils Reduce It.

Let’s talk fats. Specifically: butter.

In a major pooled analysis of three large U.S. cohorts—the Nurses’ Health Studies I & II and the Health Professionals Follow-up Study—researchers found that butter consumption was associated with increased total, cancer, and cardiovascular mortality [3].

But here’s the good news: Replacing butter with plant-based oils—like olive, soybean, and canola oil—reduced the risk of death.

The substitution analysis showed that replacing just 15 grams of butter (about 3 small pats) with 15 grams of plant-based oil (about 1 tablespoon) led to statistically significant reductions in mortality risk.

These plant oils are rich in polyunsaturated and monounsaturated fats, which have been shown in trials to:

• Lower LDL cholesterol [4]

• Reduce inflammation [5]

• Improve lipid profiles [6]

• Decrease overall mortality [7]

4. Butter, Cancer, and Inflammation

It gets worse for butter.

The same study found a strong association between butter intake and cancer mortality, especially hormone-sensitive cancers like breast and prostate [3].

Why? Saturated fat—found in high levels in butter—can increase inflammation in fat tissue and alter hormone activity, both of which are risk factors for these cancers [8,9].

And no, this wasn’t confounded by white bread or pastries—the researchers adjusted for those too.

5. Are All Plant-Based Oils the Same? Not Exactly.

Olive oil, canola oil, and soybean oil showed consistent protective effects. Corn and safflower oil? The data were weaker—possibly due to low use or degradation during cooking [3].

Some commercial corn oil is also more likely to be oxidized or partially hydrogenated, especially in older food systems [10]. So while vegetable oils generally fare better than saturated animal fats, quality and cooking method still matter.

Final Thoughts: What the Data Say

High LDL is not “just a number.” It’s a powerful driver of atherosclerosis and death.

Butter, despite its nostalgic appeal, increases risk of death. And plant-based oils? They reduce it—even in small amounts, even in real-world diets, and even over decades.

So next time someone tells you to throw out your olive oil for butter, ask them to show you the data. You now have three major studies that say otherwise.

TL;DR:

• LDL and ApoB cause plaque — not existing plaque.

• Higher LDL = worse plaque, even on keto.

• Butter increases mortality — especially from cancer and heart disease.

• Plant-based oils reduce mortality, especially olive, canola, and soybean oil.

• Replace 3 pats of butter with 1 tablespoon of plant oil to lower your risk.

References

1. Libby P et al. “Plaque Progression and Rupture in Atherosclerosis.” J Am Coll Cardiol. 2020. Link

2. Ebinger J et al. “Coronary Atherosclerosis in Individuals with Markedly Elevated LDL-C from Carbohydrate-Restricted Diets.” JACC: Advances. 2025. Link

3. Zhang S et al. “Butter and Plant-Based Oil Intake and Risk of Mortality.” JAMA Internal Medicine. 2024. Link

4. Mensink RP et al. “Effects of dietary fatty acids on serum lipids.” Am J Clin Nutr.

5. Mozaffarian D. “Omega-3 Fatty Acids and Cardiovascular Disease.” N Engl J Med.

6. Schwingshackl L et al. “PUFA and risk of CVD.” BMJ.

7. Hu FB et al. “Types of dietary fat and risk of CHD.” Am J Clin Nutr.

8. Rose DP. “Dietary fat and breast cancer.” Am J Clin Nutr.

9. Parikh M et al. “Saturated fat intake and inflammation.” J Nutr Biochem.

10. Choe E, Min DB. “Oxidative stability of oils and fats.” J Food Sci.

Want more unfiltered nutrition science?
Subscribe to FORK U — the podcast where we bust myths, decode headlines, and teach you how to use food as medicine. And follow me on TikTok & Instagram @drterrysimpson.