Cholesterol is a fat-like substance that naturally occurs in the blood and that humans need. The body produces as much cholesterol as is necessary, but several factors can alter this level.

Doctors define healthy total cholesterol levels as less than 200 milligrams per deciliter (mg/dl) of blood.

About 38% of people in the United States have total blood cholesterol levels above this figure. A person’s sex, age, body weight, and lifestyle habits can all affect their cholesterol levels.

The level of cholesterol in the body can affect heart health. Having optimum cholesterol levels also helps the body produce and maintain optimal amounts of vitamin D and hormones and promotes digestion.

In this article, we explain what cholesterol is, how it affects the body, and what the optimum levels are.

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There are three different types of cholesterol in the body:

All three types of cholesterol contain triglycerides, although about half of VLDL is triglycerides.

LDL cholesterol

People often refer to LDL cholesterol as “bad” cholesterol. This is because it can build up on the walls of the arteries, causing heart disease and other serious issues.

These cholesterol blockages can also detach from artery walls and cause blood clots.

HDL cholesterol

HDL cholesterol can absorb other cholesterol and carry it back to the liver. From there, the liver can excrete the excess matter. People often refer to HDL cholesterol as “good” cholesterol.

Optimum levels of HDL cholesterol can lower a person’s risk of heart disease and stroke.

VLDL cholesterol

The liver creates VLDL to carry triglycerides throughout the body. Triglycerides are another type of fat in the blood. They store energy from the food a person eats.

Like LDL, high levels of VLDL can lead to a buildup of plaque in the arteries and increase the risk of coronary artery disease, heart attack, or stroke.

Doctors will typically measure the total level of cholesterol in a person’s blood.

Total cholesterol levels are as follows:

  • Optimal: 125–200 mg/dl
  • Borderline high: 200–239 mg/dl
  • High: 240 mg/dl or more

Doctors calculate total cholesterol levels by summing the HDL level, the LDL level, and 20% of the triglyceride level. These numbers will tell a doctor what risk a person has of developing heart disease, type 2 diabetes, artery diseases, and other health conditions.

Blood cholesterol tests typically require people to fast for up to 12 hours before the doctor can take a blood sample.

Learn more about cholesterol tests here.

Doctors will measure the level of each type of cholesterol in a person’s blood and their overall level.

The optimal LDL cholesterol level is less than 100 mg/dl. Levels between 100 and 129 mg/dl are moderate. Borderline high results range from 130 to 159 mg/dl. Levels between 160 and 189 mg/dl are high, and a result of 190 mg/dl is very high.

The optimal HDL cholesterol level is 60 mg/dl or more. Levels lower than 40 mg/dl are too low.

The optimal VLDL level is less than 30 mg/dl.

A person’s total cholesterol levels change with age. People’s sex may also play a role.

A 2019 study involving Korean adults found that males tend to have higher total cholesterol levels between 24 and 49 years of age and that females have higher levels at the ages of 18–23 years and over 50 years.

However, in general, total cholesterol levels peaked over the age of 50 years in both sexes.

In males, average total cholesterol levels increased from 159.0 mg/dl at 18–19 years of age to 201.4 mg/dl at the age of 50–51 years.

By contrast, the average levels among females rose from 170.5 mg/dl at 20–21 years of age to a high of 212.4 mg/dl at the age of 56–57 years.

Other factors that influence cholesterol levels include:

  • Diet: Foods high in saturated fat, trans fat, and carbohydrates increase cholesterol levels. Limiting these types of foods will help regulate and decrease blood cholesterol.
  • Weight: Scientists associate many risks with having overweight or obesity, such as increased triglyceride levels. Reaching or maintaining a moderate body weight helps all factors of health, including heart disease.
  • Exercise: Engaging in physical activity for at least 30 minutes per day increases a person’s heart rate, helps maintain a moderate body weight, and lowers LDL cholesterol levels while increasing the levels of HDL cholesterol.
  • Heredity: High cholesterol can run in families.

The American Heart Association (AHA) recommends that both males and females over the age of 20 years have their cholesterol checked every 4–6 years.

High cholesterol itself does not produce any symptoms. As a result, it is important for people to get regular checkups. Doctors can use this information to discover and treat associated conditions early.

If a blood analysis finds high cholesterol levels, a doctor can help make a plan to reduce the risks. This plan may include making lifestyle changes, such as getting exercise, modifying one’s diet, taking prescription medication, and following nutrition advice.

Losing weight and exercising regularly, avoiding sugary foods and alcohol, and taking cholesterol-lowering medication may help.

Doctors typically define healthy total cholesterol levels as less than 200 mg/dl. To aid in early detection, people over the age of 20 should have their cholesterol checked every 4–6 years, according to the AHA.

High cholesterol levels can increase the risk of developing several severe conditions, such as heart disease, stroke, and coronary disease. A person’s risk further increases with obesity and poor diet.

Heart disease is the leading cause of death in the U.S. While there is no cure for the condition, a person can manage and often avoid heart disease by making lifestyle changes.