Cholesterol and the Heart Disease

How Cholesterol Affects Your Heart: What does Science Actually Says?

When I was diagnosed with high cholesterol, my doctor told me that it was bad for my heart. But why? 

Being a researcher I always have asked why? This is no different. So I digged deeper into it to learn more...

Cholesterol and the Heart: What the Science Actually Says

Cholesterol gets a bad reputation and for good reason. It’s a waxy substance your body needs for hormones and cell membranes, but when the wrong kinds build up inside your arteries they set the stage for heart attacks and strokes. That connection between cholesterol and cardiovascular disease is well established by public-health authorities. (CDC Cholesterol)

How different cholesterols affect your arteries

Low-density lipoprotein (LDL) is often called “bad” cholesterol because LDL particles deliver cholesterol to artery walls, where it can accumulate as plaque, narrow blood vessels, and eventually cause blockages. High-density lipoprotein (HDL) is called “good” because it helps remove cholesterol from artery walls and take it back to the liver. That simple framing (LDL bad, HDL good) captures the core biology clinicians use when assessing risk. (Heart & Cholesterol)

Is LDL really causal or just correlated?

Modern evidence goes beyond correlation: multiple lines of research (epidemiology, genetics, randomized trials) show that lowering LDL reduces the risk of atherosclerotic cardiovascular disease. In other words, LDL is causal and lowering it reduces events such as heart attacks and strokes. That conclusion underpins major clinical guidelines and decades of lipid research. 

What “lower is better” means in practice

Clinical guidance now generally follows the principle that “lower LDL is better,” especially for people at high cardiovascular risk. Guidelines recommend estimating each person’s overall atherosclerotic cardiovascular disease (ASCVD) risk and using that estimate to decide whether to start medications (usually statins) and how aggressively to lower LDL. Randomized trials show statins reduce heart attacks and deaths, so for many patients statin therapy is the first-line medical approach when lifestyle changes don’t get LDL low enough.

Lifestyle still matters a lot

Before pills, and alongside them, lifestyle moves are powerful. Reducing saturated and trans fats, increasing fiber, keeping active, cutting excess weight, and quitting smoking all help lower LDL and improve heart health. Public-health agencies emphasize that diet and exercise remain foundational prevention strategies even when medication is needed. 

A newcomer to the conversation: Lipoprotein(a) (Lp(a))

Not all risk is captured by LDL and HDL. Lipoprotein(a), or Lp(a), is a genetically determined particle that behaves like an extra-risky cholesterol: higher levels are linked to earlier and greater risk of heart disease and aortic valve disease. Interest in Lp(a) has surged because it identifies people at risk who otherwise have “normal” LDL. Large long-term studies and recent reviews have placed Lp(a) firmly on the clinician’s radar as an independent risk marker. 

Where treatment is headed

For decades our toolbox focused on statins and lifestyle. In the last few years clinicians and researchers have moved toward targeted therapies for lipid subtypes (for example, PCSK9 inhibitors for very high LDL and new agents that dramatically reduce Lp(a) in early trials). Those therapies are promising but remain under study for long-term outcomes and cost-effectiveness; they’re not yet part of routine care for most people. 

What you can do? 

1. Discuss with your doctor to get a full lipid panel and ask about your 10-year ASCVD (Atherosclerotic Cardiovascular Disease) risk; don’t rely on total cholesterol alone. This is what American Heart Association recommends doing to reduce your risk. (AHA Reduce ASCVD Risk)

• Eat a heart healthy diet
• Exercise
• Limit tobacco and alcohol use 
• Manage your weight if that is an issue 

    2. If your LDL is elevated or your calculated risk is high, talk about lifestyle changes and whether a         statin is appropriate; guidelines can help clinicians decide who benefits most. 

    3. Ask your clinician whether Lp(a) testing makes sense for you; especially if you have a family         history of premature heart disease or unexplained high risk. 

Always Discuss with your doctor to build a personalized plan to reduce your ASCVD risk. 

Bottom line: Cholesterol matters because it causes arterial disease when the wrong particles build up. The good news is we have clear, evidence-based ways to lower risk; lifestyle first, medications when appropriate, and emerging targeted therapies for previously untreatable risks. Talk with your doctor, bring your lipid numbers to the visit, and make a concrete plan (diet, exercise, and medication if needed) to protect your heart.