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Understanding the dangers of high cholesterol and how to keep your cholesterol levels in a healthy range

Laura Goldman,John Osborne   

Understanding the dangers of high cholesterol and how to keep your cholesterol levels in a healthy range
  • Without treatment, high cholesterol raises the risk of developing heart disease.
  • High cholesterol doesn't cause symptoms, which is why it's important to get your cholesterol levels checked every 4 to 6 years.
  • You can balance your cholesterol levels naturally by adopting a heart-healthy diet, exercising regularly, and maintaining a healthy weight.

According to the Centers for Disease Control and Prevention (CDC), nearly 94 million adults in the US have high cholesterol, which makes it a fairly common condition.

Cholesterol has an important role in the body, helping to make hormones and build healthy cells. But too much cholesterol in the blood poses a health risk. When left untreated, high cholesterol contributes to plaque buildup in the arteries, which creates blockages that increase the risk for heart disease, a heart attack, or a stroke.

What makes high cholesterol even more dangerous is the fact that it usually doesn't cause any noticeable symptoms. Many people aren't aware they have elevated cholesterol levels until they experience a life-threatening event. That's why it's recommended to ask your doctor to check your cholesterol every few years.

Here's what you need to know about cholesterol, what causes high cholesterol, and what kind of lifestyle changes and medications to expect if you're diagnosed with it.

Understanding cholesterol levels

Cholesterol is a waxy substance created by the liver to perform important functions, like building cells and hormones such as estrogen and testosterone.

Your body naturally produces all the cholesterol it needs to carry out these vital functions. But cholesterol can also enter your body through the foods you eat, and if you have an unhealthy diet, your cholesterol levels may become too high. Some people are also genetically predisposed to naturally having high cholesterol levels.

Doctors check on cholesterol levels with a blood test called a lipid panel, which measures different forms and amount of cholesterol and fats in the blood. A lipid profile typically shows results for four different types of lipids:

  • LDL (low-density lipoprotein): This is known as "bad cholesterol," because excess levels can build up in blood vessel walls and block the flow of blood, which increases your risk of heart-related illnesses. You want low LDL levels.
  • HDL (high-density liproprotein): This is known as "good cholesterol," because it helps remove LDL cholesterol from your bloodstream. You want higher HDL levels.
  • Triglycerides. When you eat an excessive number of calories, those extra calories your body doesn't need are transformed into chemical forms of fat called triglycerides. You'll want lower triglyceride levels, as they factor into your total cholesterol value.
  • Total cholesterol. This amount is calculated by adding your HDL and LDL cholesterol levels and 20% of your triglyceride level. Overall, you'll want a low total cholesterol level.

The goal is to have a proper balance of these numbers. Generally speaking, LDL and total cholesterol should be low, while HDL levels should be higher. Knowing and monitoring your numbers can ultimately help determine if you are at an increased risk for heart disease.

Cholesterol test results chart: What is considered high?

Ideal cholesterol levels vary by weight, age, and gender. But what do all the numbers mean?

In addition to looking at total cholesterol number, it's important to consider your LDL and HDL levels. Here's what's considered normal and high cholesterol for men and women over the age of 20:

Total cholesterol levels below 200 milligrams per deciliter (mg/dL) is ideal for adults, while a reading above 240 mg/dL is considered high.

For LDL levels, the lower the number, the better. LDL levels should be less than 100 mg/dL.

For HDL levels, the higher the number, the better. HDL levels are best when they're more than 60 mg/dL. Talk to your doctor to interpret these numbers and set your personal goals.

If you're under the age of 20, normal or high cholesterol levels look a bit different:

Children between the ages of 9 and 11 should have their cholesterol checked once before puberty, according to the CDC, and then once again between the ages of 17 and 21. More screenings may be necessary for children and adolescents with diabetes or obesity, as they can be at a higher risk.

Symptoms of high cholesterol

High cholesterol usually has no symptoms, which is why many people do not know they have it. You can only find out if you have it through the lipid blood test.

Important: The American Heart Association (AHA) recommends that adults have their cholesterol checked every four to six years. People at risk for heart disease should have their cholesterol levels checked more frequently.

What causes high cholesterol?

Both an unhealthy lifestyle and genetic factors can increase your risk for high cholesterol levels. The major causes of high cholesterol include:

1. Poor diet

A diet high in saturated and trans fats is one of the biggest risk factors for high cholesterol. This is because these foods affect how your liver processes cholesterol, causing it to build up in your arteries.

Saturated fat is found in the following foods:

  • Some meats like fatty cuts of beef and pork, and processed meats like hot dogs and bacon
  • Dairy products like whole milk, ice cream, butter, and cheese
  • Fried foods like fried chicken, fried fish, and french fries

As of 2020, the US Food and Drug Administration has banned manufacturers from adding artificial trans fat to processed food. However, partially hydrogenated oils that contain these fats may still be found in some products. If there is less than 0.5 total trans fat per serving, the FDA allows product labels to indicate zero trans fat.

Only 5% to 6% of the calories you consume each day should be from foods high in saturated fats, and you should avoid trans fats entirely, according to the American Heart Association.

Read on for a full list of foods that are high in cholesterol, saturated fats, and trans fats.

2. Lack of exercise

Not getting enough physical activity is another significant risk factor for developing high cholesterol. In fact, research has found that a sedentary lifestyle is a major contributor to high-cholesterol related health problems, including coronary heart disease.

A 2002 Duke University study published in the New England Journal of Medicine suggests that people who don't exercise may have smaller particles that carry cholesterol through your bloodstream. These smaller particles are more likely to clog your arteries than larger particles.

To help lower your cholesterol level, you should get at least 150 minutes of physical activity each week, says Guy L. Mintz, MD, director of Cardiovascular Health & Lipidology at Sandra Atlas Bass Heart Hospital at North Shore University Hospital in Manhasset, New York.

3. Smoking cigarettes

Research has found that smoking cigarettes is associated with higher levels of LDL cholesterol and triglycerides, and lower levels of HDL cholesterol.

The increased levels are caused by inhaling carbon monoxide when you smoke, according to the AHA. The carbon monoxide enters your bloodstream from your lungs and raises the amount of cholesterol in your arteries, causing them to harden over time and increasing your risk for heart disease.

In fact, people who smoke cigarettes are two to four times more likely to have coronary heart disease or stroke than nonsmokers, according to the CDC.

4. Being overweight

The excess fat associated with being overweight or obese can increase the amount of LDL cholesterol your liver produces. It also slows down your body's ability to remove LDL cholesterol from your blood.

Research has found that about 50% to 60% of people who are overweight and 60% to 70% of people who are obese have high cholesterol.

5. Genetics

High cholesterol can be hereditary, because your genes control how much cholesterol your body produces. Inherited high cholesterol is called familial hypercholesterolemia (FH). This condition begins at birth and increases the risk of having heart disease at an early age.

FH affects about one in 200 to 250 people in most countries. It can be managed with a healthy diet and exercise, though cholesterol-lowering medications may also be necessary.

How to improve cholesterol levels

To lower your cholesterol, Mintz says it's important to get serious about making lifestyle changes. Many people can lower cholesterol naturally — without medication — in the following ways.

Adopt a heart-healthy diet

Eating a heart-healthy diet is important for lowering your cholesterol. For example, foods that are high in soluble fiber can reduce your LDL cholesterol, while the high levels of omega-3 fatty acids in some seafood can lower your triglycerides.

Foods that can help lower your cholesterol include:

  • Vegetables like brussels sprouts, eggplant, and okra
  • Fruits like apples, grapes, and strawberries
  • Oatmeal and whole grains like oat bran and barley
  • Fish like salmon, trout, and herring
  • Lean proteins like chicken or fish

Overall, eating a Mediterranean diet that includes fruits and vegetables, fish like salmon and sardines, low-fat dairy products, and whole grains can reduce LDL cholesterol, according to a 2020 study published in the journal Lipidology.

Exercise regularly

Research has found that regular exercise helps increase the amount of HDL cholesterol in your body, which prevents LDL cholesterol from building up in your bloodstream and blocking your arteries. Exercise also helps lower your triglycerides.

For example, a 2007 meta-analysis of 25 randomized controlled trials that was published in the JAMA Archives of Internal Medicine found that the 1,404 total study participants who did aerobic exercises for about 40 minutes three times each week over a six-month period increased their HDL cholesterol levels by an average of 2.53 mg/dL.

For the most health benefits, adults should get at least 150 to 300 minutes of moderate aerobic exercise each week, according to the Physical Activity Guidelines for Americans published by the U.S. Department of Health and Human Services. This includes activities like walking, running, and swimming.

Overall, the guidelines point out that any amount of physical activity has some health benefits, and is better than being sedentary. For more information, read about the best types of exercise for heart health.

Avoid smoking

When you stop smoking cigarettes, you stop inhaling carbon monoxide. This lowers the levels of LDL cholesterol and triglycerides in your bloodstream, which will help prevent fatty deposits from building up in your arteries.

In addition, a 2011 study published in the American Heart Journal found that the level of HDL "good" cholesterol can rise about 5%, or 2.4 mg/dL, within just six weeks after quitting smoking. The higher level of HDL cholesterol can help remove more LDL cholesterol from your blood.

Lose weight

Losing weight with a healthy diet and exercise will not only lower your LDL cholesterol level, but it will also reduce your risk for other obesity-related health issues, such as type 2 diabetes.

In fact, researchers have found that people with obesity-related health issues who lose just 10% or less of their body weight can experience reduced cholesterol levels, along with other health benefits like lower blood pressure and lower blood sugar.

Learn more about how to lose weight and keep it off safely.

When to consider cholesterol medication

If lifestyle changes aren't lowering your cholesterol levels, or if you're at risk for having a heart attack or stroke, your doctor may prescribe medications called statins. These are perhaps the most effective cholesterol-lowering drugs, according to the AHA.

Statins work by preventing your liver from producing LDL cholesterol, and helping it remove LDL cholesterol that's already in your blood. Randomized trials have found that statins reduce the risk of cardiovascular events by about 25% each year for every 39 mg/dL of cholesterol.

While statins are generally considered safe, they may have some of the following side effects:

Overall, the benefits of statins far outweigh the risk of side effects, the AHA notes in a 2018 report.

"From what we know from long-term studies, they appear to be very safe," says cardiologist Eugene Yang, MD, medical director of the UW Medicine Eastside Specialty Center and chair-elect of the ACC Prevention of Cardiovascular Disease Council.

But statins won't lower cholesterol on their own, so it's important to also adopt the healthy lifestyle changes mentioned above. "One of the things that's really important is that patients don't use the medications as a way to justify eating unhealthily," Yang says.

Insider's takeaway

High cholesterol is often caused by a combination of unhealthy lifestyle factors and genetics. If you think you have high cholesterol or may be at risk, you should check in with your primary care doctor. They may also refer you to a cardiologist, who can evaluate your overall cardiovascular risk, determine the cause of your elevated cholesterol, and recommend a safe, effective, and individualized course of treatment to lower your cholesterol.