What Is High Cholesterol? Let's Take a Closer Look
When people talk about "high cholesterol," they're often referring to a general condition that includes several different types and medical terms. This can sometimes lead to confusion between doctors and patients due to the complexity of the terminology involved. In this article, we'll break down and clarify the key concepts behind the jargon.
Understanding Blood Lipids
Blood lipids refer to a broad category of fatty substances found in the bloodstream, including cholesterol, triglycerides, phospholipids, glycolipids, sterols, and steroids. Among these, cholesterol and triglycerides play the most significant roles in health. Therefore, when someone is diagnosed with high cholesterol, it usually means they have elevated levels of triglycerides, cholesterol, or both.
Total Cholesterol
Total cholesterol measures all the cholesterol in your blood. When this number is high, it's referred to as hypercholesterolemia. However, total cholesterol alone doesn't tell the whole story—it's important to look at the different types of cholesterol and how they affect your health.
Triglycerides
Elevated triglycerides are known as hypertriglyceridemia. These fats are stored in your body and used for energy, but high levels can increase your risk of heart disease. Both high cholesterol and high triglycerides can be labeled as "high cholesterol," and when both are elevated, it's called mixed hyperlipidemia.
Lipoproteins: The Transporters of Fat
Lipids can't travel through the blood on their own—they must bind to proteins called apolipoproteins to form lipoproteins. These lipoproteins are categorized by their density into five main types: chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Of these, LDL and HDL are the most clinically significant.
High-Density Lipoprotein Cholesterol (HDL-C)
HDL-C is formed when cholesterol binds with high-density lipoproteins. Often referred to as "good cholesterol," HDL helps remove excess cholesterol from the bloodstream and protects against cardiovascular disease.
Low-Density Lipoprotein Cholesterol (LDL-C)
LDL-C is known as "bad cholesterol" because it contributes to the buildup of plaque in the arteries, increasing the risk of atherosclerosis. This is why statin medications like atorvastatin, rosuvastatin, and simvastatin are commonly prescribed—to lower LDL levels.
For patients with severe coronary artery disease, the target LDL level should be below 1.8 mmol/L. For those who are generally healthy, aiming for below 3.4 mmol/L is ideal. Levels between 3.4 and 4.1 mmol/L are considered borderline acceptable, while anything above 4.1 mmol/L is considered high risk.
Understanding Apolipoproteins
Apolipoproteins are protein molecules that help transport lipids in the blood. There are over 20 types, but two of the most important ones are apolipoprotein A (ApoA) and apolipoprotein B (ApoB).
Apolipoprotein A (ApoA)
ApoA plays a key role in forming HDL particles. Higher levels are associated with better cardiovascular health and are generally considered beneficial.
Apolipoprotein B (ApoB)
ApoB is primarily involved in the formation of LDL. Elevated levels are linked to increased risk of heart disease, making it a key target for lipid-lowering therapies.
Key Lipid Indicators and What They Mean
Total Cholesterol: High levels are unhealthy and should be reduced.
Triglycerides: If within the normal range, maintain current lifestyle habits.
HDL (Good Cholesterol): If normal, aim to increase it for better protection.
LDL (Bad Cholesterol): Elevated levels are harmful and should be lowered.
Apolipoprotein A1: Slightly elevated levels are positive; keep it up!
Apolipoprotein B: High levels are dangerous and should be reduced.
ApoA/ApoB Ratio: A ratio of 0.93 is low—aim for around 1.5 for optimal health.
Putting It All Together
While doctors don't typically analyze all these numbers in detail during a routine checkup, four key markers are most often monitored: total cholesterol, triglycerides, HDL, and LDL. Among these, LDL cholesterol remains the most critical indicator, as it is a major contributor to coronary heart disease.