Researcher challenges cholesterol-focused heart disease prevention as too narrow

A medical researcher is pushing back against what he sees as an oversimplified approach to heart disease prevention—one that treats high LDL cholesterol as a near-universal threat and prescribes statins accordingly. His challenge rests partly on his own body. Seven years ago, after adopting a ketogenic diet to manage ulcerative colitis, his LDL cholesterol shot up to 15 millimoles per litre, roughly six times the upper limit doctors typically recommend. A cardiologist warned him he was at risk of a heart attack by age 30. He is now 30, has never taken a statin, and a cardiac scan found no plaque in his arteries.

The conventional wisdom is straightforward. LDL cholesterol—the particle that carries cholesterol through the bloodstream—accumulates in artery walls when levels run high, narrowing vessels and triggering heart attacks and strokes. Ireland records about 6,000 heart attacks, 7,500 strokes, and 9,000 deaths from cardiovascular disease annually. The European Atherosclerosis Society declared in 2017 that high LDL "unequivocally" causes cardiovascular disease. Doctors advise keeping total cholesterol under 5 millimoles per litre and LDL under 3. More than 200 million people worldwide take cholesterol-lowering drugs; in Ireland, approximately 520,000 are prescribed them.

Norwitz's argument is that this framework misses crucial context. He uses an analogy: oxygen is necessary for fire, but oxygen alone does not cause fire. High LDL can increase disease risk, he says, but not everyone with high LDL becomes ill. His concern is that doctors may be prescribing statins to people who are otherwise metabolically healthy—people with normal blood pressure, normal blood sugar, and low inflammation—when the drugs carry real side effects: muscle pain, weakness, elevated blood sugar, and increased diabetes risk. In his own case, when testing showed he was healthy except for his cholesterol score, he chose to watch and wait. He continued the ketogenic diet, took regular tests, and avoided medication. The seven-year cardiac scan vindicated that choice.

What matters more than LDL alone, Norwitz argues, is the full metabolic picture. Blood pressure, triglyceride levels, blood sugar, obesity, and insulin resistance all shape cardiovascular risk. A 2021 study of nearly 28,000 women found that the cardiovascular risk from insulin resistance exceeded the risk from high LDL cholesterol. Norwitz points to a recent US study of 55 people with metabolically unhealthy obesity, divided into three diet groups for six months: ketogenic, Mediterranean, and low-fat plant-based. The ketogenic diet lowered LDL as much as the plant-based diet but produced greater improvements in insulin resistance, fatty liver disease, and inflammation. His broader message is that health interventions do not operate in isolation. The same diet or drug may help one person and harm another, depending on their starting physiology.

Irish cardiologists do not entirely disagree, but they push back on the framing. Dr. Róisín Colleran, a consultant cardiologist at the Mater Private Network in Dublin, says cardiologists already consider "the interplay of different risk factors, including blood pressure, whether someone has diabetes, and if they are a smoker." They also examine particles beyond LDL—lipoprotein(a) and apolipoprotein B—which predict whether LDL will form plaque. Dr. Eamonn O'Shea, a Galway GP and cardiovascular clinical lead with the Irish College of GPs, describes the standard protocol: doctors assess diet, exercise, smoking, alcohol, medical history, family history, weight, blood pressure, kidney function, and diabetes status, then use risk-prediction tools to estimate future heart attack or stroke risk. If someone remains high-risk after three to six months of lifestyle changes, statin therapy is discussed. For the roughly 5 percent of the population with exceptionally high LDL—above 5 millimoles per litre—European guidelines recommend considering drugs even without other risk factors, because such levels can signal familial hypercholesterolaemia, a genetic condition that causes premature heart disease.

Colleran agrees that insulin resistance matters but does not endorse the ketogenic diet. She worries about increased saturated animal fat intake and the elimination of fibre-rich fruits, vegetables, and grains. She recommends the Mediterranean diet instead. Yet she supports Norwitz's core goal: encouraging patients to be active participants in their own care. Her advice is to know your numbers—get blood pressure, cholesterol, and blood sugar tested regularly—and if there is concern, address it through diet, exercise, weight management, smoking cessation, and sleep. Cardiovascular disease is 90 percent preventable, she says. The debate does not resolve into a clear winner. Instead, it points toward a shift in how doctors and patients might talk about heart health: less about a single number, more about the person behind it.