What Is Cholesterol?

Cholesterol and Where It Lurks

Burgers. Bacon. Cheese fries. What do they have in common (besides being some people's idea of delicious)? They're all high in cholesterol.

Cholesterol, a waxy substance produced by the liver and found in certain foods, is needed to make vitamin D and some hormones, build cell walls, and create bile salts that help you digest fat. Actually, your liver produces about 1,000 milligrams of cholesterol a day, enough cholesterol so that if you never touched another cheese fry, you'd be OK. But it's hard to avoid cholesterol entirely because so many foods contain it.

Too much cholesterol in the body can lead to serious problems like heart disease. Many factors can contribute to high cholesterol, but the good news is there are things you can do to control them.

Lipids are fats that are found throughout the body. Cholesterol, a type of lipid, is found in foods from animal sources. This means that eggs, meats, and whole-fat dairy products (including milk, cheese, and ice cream) are loaded with cholesterol — and vegetables, fruits, and grains contain none.

Besides the 1,000 milligrams of cholesterol that your liver produces each day, you probably consume about 150 to 250 milligrams in the foods you eat.

Because cholesterol can't travel alone through the bloodstream, it has to combine with certain proteins. These proteins act like trucks, picking up the cholesterol and transporting it to different parts of the body. When this happens, the cholesterol and protein form a lipoprotein together.

The two most important types of lipoproteins are high-density lipoproteins (or HDL) and low-density lipoproteins (or LDL). You've probably heard people call LDL cholesterol "bad cholesterol" and HDL cholesterol "good cholesterol" because of their very different effects on the body:

  • Most cholesterol is LDL cholesterol, and this is the kind that's most likely to clog the blood vessels, keeping blood from flowing through the body the way it should.
  • HDL cholesterol removes cholesterol from the blood vessels and carries it back to the liver, where it can be processed and sent out of the body.

Dangers of High Cholesterol

When you have too much cholesterol, it can be dangerous to your health. When LDL cholesterol levels are high, cholesterol is deposited on the walls of arteries and forms a hard substance called plaque. Over time, plaque causes the arteries to become narrower, decreasing blood flow and causing a condition called atherosclerosis (pronounced: ah-thuh-ro-skluh-RO-sis), or hardening of the arteries.

When atherosclerosis affects the coronary arteries (the blood vessels that supply the muscles of the heart), the condition is called coronary artery disease, which puts a person at risk for having a heart attack. When atherosclerosis affects the blood vessels that supply the brain, the condition is called cerebral vascular disease, which puts a person at risk of having a stroke.

Atherosclerosis may also block blood flow to other vital organs, including the kidneys and intestines. This is why it's so important to start paying attention to cholesterol levels as a teen — you can delay or prevent serious health problems in the future.

What Causes High LDL Cholesterol Levels?

Some of the factors that can lead to high cholesterol are:

  • Overweight: Excess weight has been linked to high cholesterol levels.
  • Heredity: If cholesterol problems or heart disease run in your family, you are at a higher risk for having problems.
  • Diet: Remember the saying "you are what you eat"? Avoid foods that are high in cholesterol, saturated fat, and trans fat, all of which increase cholesterol levels and your risk of developing heart disease.
  • Age: The risk of high cholesterol increases as you get older.

On the other hand, physical activity tends to increase HDL cholesterol levels, which reduces your chance of developing heart disease.

How Can I Lower My Cholesterol?

Some people who have high cholesterol levels need to be on medication as part of their treatment to lower it. Although most teens won't need to take medication to lower their cholesterol, it's still important to keep cholesterol in check because plaque can start to form during the teen years. To see if you have high cholesterol, talk to your doctor, who can test your cholesterol levels by taking a blood sample.

You can't change your genes, but you can do some things now to decrease your risk for heart disease later.

The 2010 Dietary Guidelines recommend that cholesterol intake should be less than 300 milligrams a day, total fat intake should be 25-35% your total calories, saturated fat should be 10% or less of the total daily calories, and trans fats should be kept as low as possible.

Also, maintain a healthy weight and get moving. Regular aerobic exercise — stuff like biking, walking, and swimming — strengthens your heart, lowers cholesterol, and helps you to lose excess weight. For people who smoke, quitting can help decrease the risk of heart disease.

Healthy Tips

Here are some helpful tips you can try:

  • Eat a diet that contains many low-cholesterol foods: fruits, veggies, whole grains (like breads and cereals), legumes (beans), and fish.
  • Eat a diet that is low in saturated and trans fat. Replace saturated and trans fats with unsaturated fats. Use liquid vegetable oil or trans fat-free margarine instead of butter, shortening, or stick margarine. Stay away from products that contain hydrogenated vegetable oils.
  • If you eat meat, try using lean meats and skinless poultry. Make sure you trim off all noticeable fat before cooking and drain the fat from the pan after browning meats.
  • Instead of frying, try boiling, broiling, baking, roasting, poaching, steaming, or sautéing.
  • Instead of whole milk, use low-fat or nonfat milk, which contains all the nutrients without all the fat. Choose other low-fat or nonfat dairy products, including yogurt, cheese, and cottage cheese. You can also substitute low-fat buttermilk or yogurt in recipes that call for cream cheese or sour cream.
  • Use trans-fat-free margarine.
  • Instead of meat, use different sources of protein including fish, beans, peas, nuts, and tofu or other soy products.
  • Instead of eggs, try just egg whites or cholesterol-free commercial egg substitutes.
  • Skip commercially prepared baked goods, which are often made with hydrogenated oils or trans fats.
  • Looking for snacks that are low in fat and cholesterol? Try fruits, raw veggies and low-fat dips, low-fat whole-grain crackers, plain unsalted popcorn or pretzels, gelatin, or low-fat yogurt.

If you are concerned about cholesterol and heart disease, talk to your doctor. Although not all the factors contributing to heart disease and high cholesterol can be controlled, many can. Start taking care of your body now and it will thank you in the future.

Reviewed by: Mary L. Gavin, MD
Date reviewed: July 2013

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.