High cholesterol is not a myth. The link between LDL cholesterol and heart disease is one of the most thoroughly studied relationships in medicine, supported by evidence from more than 200 prospective studies, genetic analyses, and randomized trials involving over two million participants and documenting more than 150,000 cardiovascular events. That said, the skeptics raise some points worth understanding, because the full picture is more nuanced than “cholesterol bad.”
Where the “Myth” Idea Comes From
Skepticism about cholesterol’s role in heart disease has roots going back decades. Early experiments fed rabbits extreme amounts of dietary cholesterol and produced sky-high blood levels, which critics argued had no relevance to humans. Others suspected those experiments triggered an inflammatory response separate from the actual process of artery disease. When early cholesterol-lowering drug trials reported unusual upticks in accidental deaths and suicides among participants, doubts deepened further. Through the 1990s and 2000s, disputes between researchers and pharmaceutical companies over statin side effects kept the controversy alive.
More recently, a new generation of skeptics has pointed to inflammation, not cholesterol, as the “real” cause of heart disease. Others argue that standard cholesterol tests are too crude to capture actual risk. Both of these claims contain a grain of truth, but they don’t add up to cholesterol being irrelevant. They point to a more detailed picture, not a different one.
How LDL Actually Damages Arteries
LDL particles aren’t just floating harmlessly through your bloodstream. When they accumulate in artery walls, they get trapped and chemically modified through oxidation. These altered particles act like a chronic irritant to the immune system. They trigger the cells lining your arteries to send out distress signals, recruiting immune cells called monocytes to the scene. Those monocytes transform into macrophages, essentially cleanup cells that try to swallow the modified LDL.
Here’s where it goes wrong: the macrophages become engorged with oxidized LDL and shift into an inflammatory state, pumping out molecules that cause even more LDL to accumulate and become modified. It’s a self-reinforcing cycle. Over years and decades, this process builds up the fatty, inflamed plaques that narrow arteries and can rupture to cause heart attacks and strokes. So cholesterol and inflammation aren’t competing explanations. LDL particles are what starts the inflammatory cascade in the first place.
The Genetic Evidence Is Hard to Dismiss
The strongest proof that LDL cholesterol causes heart disease, rather than just traveling alongside it, comes from a technique called Mendelian randomization. This approach uses natural genetic variations that give some people lifelong lower or higher LDL levels. Because these genetic variants are assigned randomly at conception, they function like a natural experiment free from the confounding factors that plague observational studies.
Multiple analyses using this method have found a consistent, dose-dependent relationship: the more LDL your arteries are exposed to over your lifetime, the higher your risk of cardiovascular disease. People born with genetic variants that lower LDL through different biological pathways all show proportionally reduced heart disease risk. The relationship is log-linear, meaning each incremental reduction in lifetime LDL exposure produces a predictable decrease in risk. This pattern holds regardless of which specific gene is responsible for lowering LDL, which makes it very difficult to argue that cholesterol is merely a bystander.
What the Skeptics Get Partly Right
Standard cholesterol tests measure the amount of cholesterol carried inside LDL particles. But what actually matters more is the number of particles bumping into your artery walls. A protein called apolipoprotein B (apoB) sits on the surface of every one of these particles, making it a direct count of how many atherogenic particles you have in circulation. In large studies, apoB consistently outperforms LDL cholesterol as a predictor of heart attacks and strokes. In one major trial, achieved LDL cholesterol levels weren’t even predictive of future cardiovascular events once apoB levels were accounted for.
This matters in practical terms. Some people have lots of small, cholesterol-depleted LDL particles. Their standard LDL number looks reassuringly low, but their actual particle count (and risk) is high. Others have fewer, cholesterol-enriched particles. Their LDL number looks alarming, but their true risk is lower than the number suggests. Data from the Québec Cardiovascular Study found that the combination of small LDL particles and a high particle count produced a sixfold increase in heart disease risk, far more than either factor alone.
So the skeptics are onto something when they say a standard cholesterol panel can mislead. The solution isn’t to ignore cholesterol. It’s to measure it more precisely.
The Question of Very Low LDL
Another concern raised by cholesterol skeptics is that driving LDL too low could be dangerous. There is some data worth considering here. A long-term study following a nationally representative group for a median of 23 years found that people with naturally occurring LDL below 70 mg/dL had a 45% higher risk of dying from any cause compared to those in the 100 to 130 mg/dL range. The risk of stroke death was four times higher in the very low LDL group, driven largely by hemorrhagic stroke (bleeding in the brain rather than a clot).
Context matters, though. In that study, naturally very low LDL in the general population may reflect underlying illness, malnutrition, or genetic conditions rather than healthy lipid levels. People who start with elevated LDL and lower it through treatment show clear benefits. Current guidelines recommend getting LDL below 70 mg/dL for people with established heart disease, and below 55 mg/dL for those at very high risk (defined as people who’ve had multiple cardiovascular events or a combination of a major event plus additional risk factors like diabetes, smoking, or age over 65). These targets are based on trial data showing fewer heart attacks and strokes at those levels.
What This Means for You
If you’ve encountered claims that cholesterol is irrelevant to heart disease, the evidence says otherwise. LDL particles are a direct, causal driver of the arterial damage that leads to heart attacks and strokes. The relationship is dose-dependent and time-dependent: the higher your LDL and the longer it stays elevated, the more cumulative damage it does.
Where the conversation deserves more nuance is in how cholesterol is measured. A standard LDL number is useful but imperfect. If you want a sharper picture of your cardiovascular risk, asking about apoB testing gives you a more accurate count of the particles that actually matter. People with metabolic syndrome, insulin resistance, or high triglycerides are especially likely to have a mismatch between their LDL cholesterol reading and their true particle-driven risk.
The “cholesterol is a myth” narrative takes real gaps in how we measure and communicate cholesterol risk and stretches them into a wholesale rejection of decades of converging evidence. The science isn’t perfect, and individual risk is more complex than a single number on a lab report. But the core relationship between LDL and heart disease is as well-established as anything in cardiovascular medicine.