Does LDL Really Cause Heart Disease?

22 Oct 2026 · 1 min

Watch on YouTube

1:02

In this 70‑second YouTube short, Nick Norwitz challenges the common medical shorthand that “LDL is causal for cardiovascular disease.” He explains that while LDL cholesterol is indeed part of the causal chain leading to heart disease, causality does not automatically imply that LDL is the most important risk factor, that it alone can cause disease, or that it must be targeted for treatment. Norwitz uses a personal analogy—comparing a biological male’s equipment being a causal factor for sexually transmitted infections—to illustrate that a causal variable isn’t always something you should eliminate. He warns that conflating causality with importance can mislead clinicians and the public, and he points viewers to a longer article where he expands on how cholesterol science has become dogmatic. The key takeaway is that size (i.e., the magnitude of LDL’s effect) matters more than merely labeling it causal.

Chapters

If you understand what I say about LDL cholesterol in the next 70 seconds, you'll understand something about heart disease that many doctors still get wrong. We hear all the time that LDL is causal for cardiovascular disease, but what does that even mean? Causal means that something is involved in a causal chain, like dominoes. It does not mean it's the most important variable, nor that it's sufficient to cause disease on its own, nor that it needs to be treated. Here's an analogy. As a biological male, my equipment is a causal factor in me contracting sexually transmitted diseases, but does that mean I should remove the causal variable to reduce my risk? I certainly hope not. Just because something is causal doesn't mean eliminating or reducing it is always smart. I go into a lot more detail in my article on how cholesterol science became a religion, linked below— this is just foreplay— but here's the takeaway for this short: When we conflate causality and importance, we risk losing sight of the bigger picture, and when it comes to cardiovascular risk, size matters.