Rethinking cholesterol: How our understanding of heart risk has evolved

For many years, heart disease risk was often explained with a single number from a routine blood test.

Total cholesterol. If that number was high, concern followed. The reasoning seemed straightforward. Cholesterol is found in the plaques that narrow arteries. Lower the cholesterol and risk should fall. Early public health campaigns focused heavily on reducing dietary fat, especially saturated fat, because it can raise certain cholesterol levels in the blood.

Over time, researchers discovered that cholesterol does not float freely in the bloodstream. It travels inside particles called lipoproteins. Two of the most discussed are LDL and HDL. LDL, or low-density lipoprotein, carries cholesterol from the liver to tissues throughout the body. HDL, or high-density lipoprotein, helps carry cholesterol back to the liver for processing and removal.

This added nuance. Two people with the same total cholesterol could have different proportions of LDL and HDL, and therefore different levels of risk. Doctors began looking not just at total cholesterol, but at LDL levels, HDL levels, and their ratio.

As science advanced, attention turned to how these particles behave. Not all LDL particles act the same way. Some are small and dense, making them more likely to slip into the lining of an artery. Some become oxidized, meaning they undergo a chemical change in the presence of inflammation or oxidative stress. Oxidized LDL appears more reactive inside the vessel wall.

Researchers also began measuring LDL particle number, which estimates how many LDL particles are circulating, not just how much cholesterol they carry. The conversation shifted from simple quantity to particle characteristics and the internal environment in which they circulate.

At the same time, another marker gained attention. Triglycerides. These are fats carried in the blood that often rise when the body is processing excess calories, especially from refined carbohydrates and sugars. Elevated triglycerides frequently occur alongside low HDL, increased waist size, higher fasting insulin, and fatty liver. Insulin is the hormone that helps regulate blood sugar.

When cells respond poorly to insulin, a condition known as insulin resistance, triglycerides often rise. Because insulin resistance is linked to both heart disease and type 2 diabetes, some clinicians view triglycerides as a window into overall metabolic health rather than just a lipid measurement.

These developments have led to thoughtful differences in emphasis. Many cardiologists continue to highlight LDL exposure over time as a central driver of plaque buildup, also known as atherosclerosis. Genetic conditions that cause extremely high LDL can lead to early heart disease even when triglycerides are normal. Large clinical trials have shown that lowering LDL reduces heart attacks and strokes. This body of evidence supports the importance of LDL.

Others look more broadly at metabolic context. They note that LDL may be more harmful in the presence of chronic inflammation and insulin resistance. In this view, triglyceride levels and the triglyceride to HDL ratio can offer insight into how the body is handling carbohydrates and energy.

A person with moderately elevated LDL but low triglycerides and stable blood sugar may be viewed differently from someone with modest LDL but high triglycerides and signs of metabolic strain. Both patterns matter, though the interpretation may vary.

Nutrition advice has evolved alongside these discussions. Earlier guidance centered on lowering saturated fat to reduce LDL. Over time, it became clear that what replaces saturated fat in the diet matters. Replacing it with refined carbohydrates can raise triglycerides and worsen insulin resistance. Industrial trans fats are now widely recognized as harmful. Current conversations often focus less on a single nutrient and more on overall dietary patterns, food quality, fiber intake, and long-term lifestyle habits.

Today, cardiovascular risk assessment considers multiple factors together. Total cholesterol, LDL, HDL, triglycerides, blood pressure, blood sugar, age, and family history all contribute to the picture. Rather than discarding older measures, modern medicine has layered new insights onto earlier discoveries.

The evolution of cholesterol science reflects growing refinement. Different perspectives emphasize different aspects of the same process, with meaningful overlap among them. Interpreted together, these markers provide a fuller understanding of heart health than any single number alone.

Seth Schneider is a health columnist for the Bonner County Daily Bee.