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Understanding Cholesterol

Editor's Note: This article is out of date. Please go to for the latest information.

You probably know that fried chicken, a doughnut or a loaded double cheeseburger are not the best foods to put in your body. Why? Because foods like these are packed with unhealthy fats and lack many of the important nutrients for heart health. 

While our bodies need a certain amount of cholesterol to work properly, too much of the “bad” type can be dangerous. Over time, cholesterol and fat can collect in the inner walls of the arteries—including the ones that supply blood to the heart. This build up can cause atherosclerosis, a narrowing of the arteries and a major cause of cardiovascular disease. People with high levels of low-density lipoprotein (LDL), also called the “bad” cholesterol, are at greater risk for cardiac events.

The good news is that high cholesterol is often preventable and treatable. Studies show that keeping LDL low can not only prevent someone from developing clogged or narrowed arteries in the first place (primary prevention), doing so also helps reduce the likelihood of a heart attackstroke or related death among people who already have heart disease (secondary prevention). The opposite is true too; those with high levels of high density lipoprotein (HDL)—the “good” cholesterol—tend to have cleaner arteries and lower risk of heart attack and stroke. That’s because HDL acts like a scavenger, helping to find harmful cholesterol and removing it from your arteries.

The challenge is that there are often no signs or red flags of having too much bad cholesterol until it starts to affect your arteries. For this reason, it is important to know your cholesterol numbers

Increasingly, research shows that keeping LDL levels low is an essential part of staying heart healthy. Adopting a healthy diet, getting regular exercise, keeping weight well managed, and, in some cases, taking medication, can go a long way to help. 

What is cholesterol? 

Cholesterol is a waxy, fat-like substance that travels through the blood in carrier vehicles called lipoproteins. Cholesterol is made by the liver and serves a variety of functions. For example, it helps create the outer coating of our cells and aids the body in making vitamin D and certain hormones. 

Excess amounts of dietary fats get absorbed by the body and synthesized into cholesterol. 

Saturated and trans fats raise LDL levels in the blood, thereby increasing the risk of heart disease. Foods that are high in animal fat (full-fat milk, cheese, meat) and/or prepared with butter, shortening or partially hydrogenated oils and sweets (cookies and cakes) are often the main culprits. There is some evidence that trans fats can carry a double-whammy—raising LDL and lowering HDL.

How do I know which foods have saturated or trans fats?

  1. Read food labels.
  2. Pay attention to what it looks like when it’s left out. Saturated fats, such as butter or shortening are usually solid at room temperature. On the other hand, olive oil remains liquid and is considered a healthier type of dietary fat (monounsaturated).
  3. Steer clear of hydrogenated or partially-hydrogenated oil.
  4. Remember, some food that seem healthy may have hidden sources of extra calories and fat. Some salad dressings (and other sauces) can be laden with so much saturated fat that they can defeat what you are trying to do by eating the salad.

What does it feel like?

Many people don’t know that they have high levels of harmful cholesterol. That’s because there are usually no signs or symptoms associated with an early build up of fatty plaques in the arteries. It’s not until there may be a significant blockage of the artery (70 percent or more) that someone might notice something is wrong. For example, they may have chest pain, pain in the arms or jaw, nausea, sweating, or shortness of breath—these usually occur when the blood supply to the heart is being slowed or blocked. Unfortunately, these blockages or plaques, can rupture and cause major problems, even when they are much smaller and without causing any early symptoms. That is why, for some people, the first sign may be a heart attack or stroke.

Cholesterol can affect the body in a number of ways

Elevated levels of LDL-C can:

  • Cause irritation or swelling of the artery walls
  • Promote the formation of blood clots
  • Reduce or block the flow of blood through the arteries

That’s why—even if you’re feeling good—it’s a good idea to get your cholesterol checked. Your doctor will consider your cholesterol numbers along with any other factors that make heart disease or stroke more likely to occur (e.g., age, diabetes, high blood pressure, smoking). 

What puts you at risk? 

High LDL and total cholesterol are generally related to:

  • Poor lifestyle habits – eating food rich with unhealthy fats and carbohydrates, not exercising regularly, being overweight/obese or smoking
  • Low HDL levels
  • Older age  
  • High blood pressure
  • Family history of early heart disease
  • Diabetes
  • African American race 

Keeping tabs on your cholesterol

A simple blood test—called a lipid panel—is used to check the amount of cholesterol in your blood. Cholesterol is measured in milligrams (mg) per deciliter (dL) of blood—mg/dL. The test provides four measures: 

  • Total or overall cholesterol
  • LDL or “bad” cholesterol
  • HDL or the “good” cholesterol
  • Triglycerides

It’s important to track your cholesterol over time, especially because there are often no signs and symptoms of early build up of fat and cholesterol in the artery walls. Talk with your health care provider about how often your cholesterol should be checked and what numbers would be ideal for you.

Infographic: Cholesterol

(Click to view)

Treatments to improve your cholesterol numbers

Your treatment plan will be based on your doctor’s assessment of your overall risk for cardiovascular disease—for example, whether you already have atherosclerosis or have a high chance of developing it (based on a standard risk assessment). Recommended treatments will also depend on:

  • Your cholesterol levels
  • Other existing conditions
  • Previous treatments tried (if applicable)
  • Personal choice 

Trying to lower elevated levels of LDL most often comes down to making healthier lifestyle choices. In fact, the choices we make every day can influence our cholesterol. 

Here are four things that can make a difference: 

  1. Eat a heart-healthy diet, such as the Mediterranean or DASH diets
  2. Exercise regularly 
  3. Stay at a healthy weight and lose any extra pounds
  4. Don’t smoke, and stay away from secondhand smoke 

Many people with elevated LDL also need to take medication. 

Making lifestyle changes 

Adopting a heart-healthy diet and getting regular exercise are the most important steps you can take to prevent or control cholesterol problems and heart disease. Here are some general tips: 

  • Get physical. Aim to get a minimum of 30 minutes of (moderate-intensity) activity at least five times a week. Activities might include a brisk walk, jogging, riding a bike, swimming—even gardening or heavy housework. If you don’t have a 30-minute block of time free, even 10-minute bursts of activity three times throughout the day is helpful. Consider wearing a device that keeps track of the number of steps you take each day so that you know your starting point.
  • Take time to read and understand food labels, and pay special attention to the amount of saturated fats, trans fats (hydrogenated or partially hydrogenated oils) and sugar content.
  • Try to avoid full-fat dairy products, processed foods, and foods high in salt (sodium) and preservatives.
  • Substitute butter or margarine for healthier fats such as olive oil, avocados and a handful of almonds (remember, fat that becomes solid on the counter should probably be avoided). Nuts, fish, certain oils (olive, canola and peanut oils) and other foods rich in omega-3 fatty acids are good choices.
  • Consider keeping a food diary so you can see what you are eating and what dietary habits you might need to change.
  • Ask about seeing a dietitian or nutritionist who can help you meal plan and provide dietary strategies for lowering LDL or triglycerides, and improving your sugar levels and boosting your energy.
  • As with any goal, start small. Make sure you are setting yourself up for success.
  • Limit alcohol. Too much alcohol can raise triglyceride levels and blood pressure.

Eat this, not that

 Limit or Avoid

 Eat More

  • Trans fats (try to avoid)
  • Saturated fats (should only be ~5% of daily caloric intake)
  • Sweets, sugar-sweetened drinks
  • Red meat
  • Alcohol 

Unhealthy diets are high in saturated and trans fat, sodium and calories.

  • Whole grains and other high-fiber foods
  • Fresh fruits and vegetables
  • Low-fat dairy options
  • Olive oil
  • Certain nuts
  • Fish
  • Soy 

Talk to your health care team about the Mediterranean and DASH diets.


Many people who have excess LDL also need to take lipid-lowering medications at some point. This is especially true for people with atherosclerotic cardiovascular disease or those who are at high risk for developing it. 

Statins—in combination with lifestyle changes—are still the drug treatment of choice. Research has shown that the use of statins can reduce the risk of cardiac events like heart attack, stroke and related death. There are at least seven statins available, and they work in different ways; for example by:

  • Reducing the amount of cholesterol made by the liver
  • Removing cholesterol from the blood
  • Reducing cholesterol in plaque
  • Reducing inflammation from plaque
  • Preventing plaque from dislodging or forming a clot that may block an artery 

As with any medication, it is important to tell your doctor about any side effects or problems from statins. Though side effects are not common, your doctor may decide to:

  • Order a blood test to find out if there may be another cause of your symptoms
  • Lower the dose of the statin you are taking
  • Switch you to a different statin
  • Prescribe an alternative dosing schedule 

Other (non-statin) medications include: 

No matter which medication your doctor prescribes, take your medications exactly as directed—that’s the only way to make sure they work as intended. If you have side effects or concerns, talk with your doctor before making any changes. Your local pharmacist is a good resource if you have questions.

Did You Know?

  • People with high total cholesterol are twice as likely to develop heart disease.
  • About 1 in 3 American adults has high LDL.
  • Recent studies suggest cholesterol levels fluctuate based on the time of year. Cholesterol levels tend to be more unfavorable in the colder months.
  • For women, knowing their cholesterol level becomes even more important after menopause.

Talking to your health care team

Your health care team will work with you to help prevent or treat high cholesterol and support your overall cardiovascular health. Here are some questions you may want to ask:

  • What is my cholesterol?
  • What’s the difference between LDL and triglycerides?
  • Will exercise and diet alone be enough to lower my cholesterol?
  • How much exercise should I be getting? What types of activities are best for me?
  • Are there foods I should avoid/eat more of?
  • Do I need medication? If so, which medication and why?
  • When can we expect to see a difference?
  • What side effects should I watch for?
  • I know statins are usually the first drug therapy, but what can you tell me about non-statin medications?
  • What can I do to raise my “good” cholesterol?
  • How often do I need to get my cholesterol level checked?
  • What about my other risk factors for cardiovascular disease?

Helpful resources

To learn more about cholesterol, click here. In addition to resources on, you can find out more by visiting:

Familial Hypercholesterolemia Foundation 

American Heart Association 

National Heart, Lung and Blood Institute

Published: September 2015; updated February 2017
Medical Reviewers: Michael D. Shapiro, MD, FACC, Oregon Health & Science University, and Filipe A. Moura, MD, PhD Student, State University of Campinas (Brazil)

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LDL – the bad cholesterol. LDL is the cholesterol that gums up your arteries and causes the buildup of blockages. It’s also the cholesterol that is toxic to the lining of your arteries, increasing the risk of a heart attack or stroke.

Infographic: Cholesterol


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