Cholesterol is a waxy, fat-like substance found in all cells of the body. It is essential for the production of hormones, vitamin D, and substances that help digest food. The liver produces all the cholesterol the body needs, but cholesterol also comes from the foods we eat, especially from animal products such as meat, poultry, and whole-milk dairy products.
Despite its bad reputation, cholesterol is not harmful. In fact, it is essential for a number of biological processes. Problems arise when cholesterol levels are out of balance. In turn, other health conditions can also increase your risk of high cholesterol.
Cholesterol is carried in the blood by lipoproteins. There are two main types:
- Low-density lipoprotein (LDL): Often called “bad” cholesterol, LDL carries cholesterol to the arteries. High LDL cholesterol levels can lead to a buildup of cholesterol in your arteries, increasing your risk of heart disease and stroke
- High-density lipoprotein (HDL): Known as “good” cholesterol, HDL carries cholesterol away from your arteries and back to your liver, where it can be removed from your body. Higher HDL cholesterol levels are associated with a lower risk of heart disease.
- Another important type of lipid in your blood is Triglycerides: These are fats from the foods you eat that circulate in your body, possibly stored in fat cells. Triglycerides are not actually a type of cholesterol, but their levels are measured along with HDL and LDL to see if you are at risk for atherosclerosis.
What is a dangerous cholesterol level?
Recommended cholesterol levels: Cholesterol levels are measured in milligrams (mg) per deciliter (dL) of blood. The recommended ranges for adults are:
- Total cholesterol: Below 200 mg/dL (desirable)
- LDL cholesterol: Below 100 mg/dL (optimal)
- HDL cholesterol: 60 mg/dL or higher (protective)
- Triglycerides: Below 150 mg/dL (normal)
LDL cholesterol is considered high and dangerous: An LDL level of 160 mg/dL or higher is considered high and increases the risk of heart disease, especially when combined with other risk factors such as smoking, high blood pressure, or diabetes. Levels above 190 mg/dL are considered very high and usually require medical treatment.
Low HDL cholesterol: An HDL level below 40 mg/dL for men or below 50 mg/dL for women is considered a risk factor for heart disease. Low HDL means there is less “good” cholesterol to help remove excess LDL from the blood.
High Triglycerides: A triglyceride level of 200 mg/dL or higher is considered high and can be dangerous, especially when combined with low HDL or high LDL.
What are the risks of high cholesterol?
1. Atherosclerosis
One of the most significant risks of high cholesterol is the development of atherosclerosis, a condition in which cholesterol and other substances build up in the artery walls, forming plaque. These plaques can narrow the arteries and restrict blood flow.
2. Heart Attack and Stroke
When plaque ruptures, it can form a blood clot that blocks blood flow. If this happens in a coronary artery, it can cause a heart attack. If it happens in the brain, it can lead to a stroke.
3. Peripheral Artery Disease
High cholesterol can also lead to peripheral artery disease (PAD), which affects blood flow to the limbs, often causing pain and increasing the risk of infection or even amputation in severe cases.
Risk Factors for Dangerous Cholesterol Levels
Several factors can increase your chances of developing high cholesterol, including:
- Poor diet: Eating a lot of saturated fat, trans fat, and foods high in cholesterol can increase LDL levels.
- Lack of exercise: Physical inactivity can lower HDL and increase LDL and triglycerides.
- Smoking: Smoking damages blood vessels and lowers HDL cholesterol.
- Obesity: Being overweight or obese is strongly linked to higher LDL, higher triglycerides, and lower HDL.
- Genetics: Familial hypercholesterolemia is a genetic condition that results in extremely high LDL levels.
- Age and gender: Cholesterol levels tend to increase with age. Women typically have higher HDL levels than men, but after menopause, LDL levels can increase significantly.
- Medical conditions: Diabetes, hypothyroidism, and some kidney and liver diseases can increase cholesterol levels. People with PAD should be careful and check their extremities for cuts, scrapes, and signs of infection.
