In the blood, cholesterol is transported by lipoproteins known as HDL and LDL. HDL takes cholesterol to the liver for release, while LDL brings it to the arteries, where it can cause plaque buildup.

Cholesterol frequently gets a bum rap, but it’s necessary for your body to function properly. Your body uses cholesterol to make hormones and vitamin D and support digestion.

Your liver generates enough cholesterol to handle these tasks, but your body doesn’t just get cholesterol from your liver. Cholesterol is also in foods such as meat and dairy. If you eat a lot of these foods, your cholesterol levels may become too high.

There are two main types of cholesterol: high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Lipoproteins are made of fat and proteins. Cholesterol moves through your body while inside lipoproteins.

HDL is known as “good cholesterol” because it transports cholesterol to your liver to be released from your body. HDL helps rid your body of excess cholesterol so it’s less likely to end up in your arteries.

LDL is called “bad cholesterol” because it takes cholesterol to your arteries, where it can collect in your artery walls. Too much cholesterol in your arteries may lead to a buildup of plaque known as atherosclerosis. This can increase the risk of blood clots in your arteries.

If a blood clot breaks away and blocks an artery in your heart or brain, you may have a stroke or heart attack.

Plaque buildup may also reduce blood flow and oxygen to major organs. Oxygen deprivation to your organs or arteries may lead to kidney disease or peripheral arterial disease, in addition to a heart attack or stroke.

According to the Centers for Disease Control and Prevention (CDC), nearly 12 percent of people in the United States have high cholesterol. You may not even know it because high cholesterol doesn’t cause noticeable symptoms.

The only way to find out if your cholesterol is high is through a blood test that measures cholesterol in milligrams per deciliter of blood (mg/dL). When you get your cholesterol numbers checked, you’ll receive results for:

  • Total blood cholesterol. This includes your HDL, LDL, and 20 percent of your total triglycerides.
  • Triglycerides. This number should be below 150 mg/dL. Triglycerides are a common type of fat. If your triglycerides are high and your LDL is also high or your HDL is low, you’re at risk of developing atherosclerosis.
  • HDL. The higher this number, the better. It should be at least higher than 55 mg/dL for females and 45 mg/dL for males.
  • LDL. The lower this number, the better. It should be no more than 130 mg/dL if you don’t have heart disease, blood vessel disease, or diabetes. It should be no more than 100 mg/dL if you have any of these conditions or high total cholesterol.

Lifestyle factors that may cause high cholesterol are:

  • obesity
  • a diet high in red meat, full-fat dairy products, saturated fats, trans fats, and processed foods
  • a large waist circumference (over 40 inches for men or over 35 inches for women)
  • lack of regular exercise

According to a 2013 review, smokers typically have lower HDL cholesterol than nonsmokers. Research shows that quitting smoking can increase HDL. If you smoke, talk with a doctor about smoking cessation programs or other methods to quit smoking.

It’s unclear if stress directly causes high cholesterol. Unmanaged stress may lead to behaviors that can increase LDL and total cholesterol, such as:

  • overeating fatty foods
  • inactivity
  • increased smoking

In some cases, high LDL is inherited. This condition is called familial hypercholesterolemia (FH).

According to the Family Heart Foundation, FH is caused by a genetic mutation that affects the ability of a person’s liver to get rid of extra LDL cholesterol. This may lead to high LDL levels and an increased risk of heart attack and stroke at a young age.

To treat high cholesterol, doctors often recommend these lifestyle changes:

  • stopping smoking, if you smoke
  • eating a balanced, nutritious diet
  • exercising regularly
  • reducing stress
  • maintaining a moderate weight

Sometimes lifestyle changes aren’t enough, especially if you have FH. You may need one or more medications, such as:

  • statins to help your liver get rid of cholesterol
  • bile-acid-binding medications to help your body use extra cholesterol to produce bile
  • cholesterol absorption inhibitors to prevent your small intestines from absorbing cholesterol and releasing it into your bloodstream
  • injectable medications that cause your liver to absorb more LDL cholesterol

Medications and supplements to reduce triglyceride levels may also be used, such as omega-3 fatty acids and fibrates.

Learn more: Managing high cholesterol without medication.

The American Heart Association recommends eating these foods to help reduce total cholesterol and increase HDL:

  • a range of fruits and vegetables
  • whole grains
  • skinless poultry, lean pork, and lean red meat
  • baked or grilled fatty fish, such as salmon, tuna, or sardines
  • unsalted seeds, nuts, and legumes
  • vegetable or olive oils

These foods may increase LDL cholesterol and should be avoided or rarely eaten:

  • untrimmed red meat
  • fried foods
  • baked goods made with trans fats or saturated fats
  • full-fat dairy products
  • foods with hydrogenated oils
  • tropical oils

High cholesterol can be concerning, but in most cases, it’s a warning signal. Being diagnosed with high cholesterol doesn’t mean you’ll develop heart disease or have a stroke, but it should still be taken seriously.

If you have high cholesterol and you take steps to reduce it, your risk of heart disease and stroke will most likely decrease. Lifestyle changes that help reduce cholesterol also support your overall health.

You’re never too young to start thinking about preventing high cholesterol. Eating a balanced, nutritious diet is an important first step. Here are some changes you can make today:

  • Swap traditional pasta with whole wheat pasta, and swap white rice with brown rice.
  • Dress salads with olive oil and a splash of lemon juice instead of high fat salad dressings.
  • Eat more fish. Aim for at least two servings of fish per week.
  • Swap soda or fruit juice with seltzer water or plain water flavored with fresh fruit slices.
  • Bake meat and poultry instead of frying meats.
  • Use low fat Greek yogurt instead of sour cream. Greek yogurt has a similar tart flavor.
  • Opt for whole grain cereals instead of sugar-filled varieties. Try topping them with cinnamon instead of sugar.

Learn more: The practical 12-step guide to breaking up with sugar.

Exercise may also have a positive impact on your cholesterol levels. If you’re inactive most of the day, make an effort to move more. If you work at a desk, set an alarm on your cellphone or computer, or get a fitness tracker to remind you to get up and move for 5 minutes each hour.

Try to fit in at least 30 minutes of exercise daily. Walking, swimming, or riding a bike are great options.

If you smoke, talk with a doctor about how to stop. Smoking increases your risk of:

  • high cholesterol
  • high blood pressure
  • heart disease
  • many types of cancer

If you don’t know your cholesterol numbers, ask your doctor about getting tested, especially if you have a family history of high cholesterol or heart disease. The earlier you know your cholesterol numbers, the sooner you can take steps to manage them.