What Causes High Cholesterol? Risk Factors, Diet, and What You Can Do

High cholesterol affects nearly 94 million American adults, yet many people have no idea their levels are elevated until a routine blood test reveals the problem. Understanding what causes high cholesterol is the first step toward protecting your heart and taking control of your health.

The causes of high cholesterol fall into two broad categories: factors you can control and factors you cannot. A 2019 review in the Journal of the American College of Cardiology found that both genetic and lifestyle factors contribute significantly to elevated cholesterol levels (Ference et al., 2017).

How Cholesterol Works in Your Body

Cholesterol is a waxy substance that your liver produces naturally. Your body needs it to:

• Build and repair cell membranes
• Produce hormones like estrogen and testosterone
• Create bile acids that help digest fats

About 80% of the cholesterol in your blood is made by your liver. The remaining 20% comes from food. When you eat a lot of saturated fat or have genetic factors that impair cholesterol clearance, your levels can rise above healthy ranges.

Two types of cholesterol matter most:

• LDL (low-density lipoprotein): Often called “bad” cholesterol. It carries cholesterol to your arteries, where it can build up as plaque. High LDL is a major risk factor for heart disease and stroke.
• HDL (high-density lipoprotein): Often called “good” cholesterol. It removes cholesterol from your arteries and transports it back to the liver for disposal. Higher HDL is generally protective.

Keeping LDL low and HDL at a healthy level is key for long-term heart health.

Dietary Causes of High Cholesterol

Saturated Fat

Saturated fat is the single biggest dietary driver of high LDL cholesterol. It raises LDL by reducing the number of LDL receptors on liver cells, which slows the removal of LDL from your blood.

A meta-analysis in The BMJ showed that replacing saturated fat with unsaturated fat reduces LDL cholesterol and lowers cardiovascular risk (Sacks et al., 2017). The American Heart Association recommends limiting saturated fat to less than 6% of total daily calories.

Common sources of saturated fat include:

• Red meat and processed meats (beef, sausage, bacon, hot dogs)
• Full-fat dairy products (butter, cheese, whole milk, cream)
• Tropical oils (coconut oil, palm oil, palm kernel oil)
• Baked goods made with butter, cream, or lard

Swapping these for lean proteins and plant-based fats can significantly improve your cholesterol profile.

Trans Fats

Trans fats are the most harmful dietary fats for cholesterol. They:

• Raise LDL cholesterol

Genetic Causes of High Cholesterol

Familial Hypercholesterolemia (FH)

Familial hypercholesterolemia is an inherited condition that affects about 1 in 250 people worldwide. People with FH have a genetic mutation that impairs their liver's ability to remove LDL cholesterol from the blood, resulting in extremely high LDL levels from birth. If your LDL is above 190 mg/dL or you have a family history of early heart disease before age 55 in men or 65 in women, ask your doctor about genetic testing.

Family History

Even without FH, having close relatives with high cholesterol or early heart disease increases your risk. Multiple genes influence how your body produces, absorbs, and metabolizes cholesterol. You cannot change your genetics, but knowing your family history helps you and your doctor make better decisions about screening and treatment.

Medical Conditions That Affect Cholesterol

Several health conditions can raise cholesterol levels. Type 2 diabetes increases triglycerides and small, dense LDL particles while lowering HDL. Hypothyroidism slows the liver's ability to clear LDL from the blood. Chronic kidney disease disrupts lipid metabolism and can raise triglycerides. Polycystic ovary syndrome (PCOS) is associated with insulin resistance and unfavorable lipid profiles. Liver disease can impair cholesterol processing and bile acid production.

Certain medications can also affect cholesterol levels. These include some blood pressure medications (thiazide diuretics, beta-blockers), corticosteroids, immunosuppressants, and some HIV antiretroviral drugs. Never stop taking a medication without consulting your doctor.

Age, Sex, and Cholesterol

Cholesterol levels naturally change with age. Total cholesterol tends to rise through middle age. In women, menopause often triggers a significant increase in LDL cholesterol due to declining estrogen levels, which normally help keep LDL in check. Men typically develop higher cholesterol earlier in life, but women often catch up after menopause.

What You Can Do About High Cholesterol

The good news is that most causes of high cholesterol are modifiable. Reduce saturated fat intake by choosing lean proteins and plant-based oils. Increase soluble fiber from oats, beans, lentils, fruits, and vegetables. Exercise regularly with at least 150 minutes of moderate activity per week. Maintain a healthy weight through balanced nutrition. Quit smoking to improve HDL and overall cardiovascular health. Limit alcohol to moderate amounts. Manage underlying conditions like diabetes or hypothyroidism with your healthcare provider.

If lifestyle changes alone are not sufficient, your doctor may recommend statin medications or other cholesterol-lowering drugs.

The Bottom Line

High cholesterol results from a combination of diet, lifestyle, genetics, and underlying medical conditions. The most common controllable causes are saturated fat intake, physical inactivity, and excess body weight. The encouraging reality is that most people can significantly improve their cholesterol through dietary changes, exercise, and weight management. Regular monitoring with a lipid panel helps you track progress, and tools like Cole AI make it easy to stay on top of your numbers and understand what they mean for your long-term heart health.