Why cholesterol levels matter: Normal ranges for HDL and LDL cholesterol

Not all cholesterol is bad. In fact, your body needs cholesterol in order to function. Still, unhealthy cholesterol levels are a major risk factor for heart disease and other serious medical conditions.

Cholesterol isn’t something you can feel, so regular cholesterol testing is important. If you know your levels are high, you can take steps to lower your cholesterol levels. But if you don’t get tested, the first time you learn you have high cholesterol could be after a stroke or heart attack.

So, what’s cholesterol? What should your cholesterol levels be? How do you get your cholesterol tested? And what do triglycerides have to do with cholesterol? Below, we answer these questions and more.

What is cholesterol? A waxy, fat-like substance your body needs

Cholesterol is a type of lipid, which are waxy, fatty or oily substances that your body makes. They act as the building blocks for all of your cells and help support many different processes in your body. In particular, cholesterol is important because it helps with:

• Hormone regulation – Cholesterol aids in the production of hormones, including sex hormones.
• Cell membranes – Cholesterol provides protective layers around our cells, controlling what substances can enter and exit. Without cholesterol, cells wouldn’t have the stability to function properly.
• Bile production – Your liver needs cholesterol to produce bile, which helps your body digest fats from the food you eat.
• Vitamin D processing – When we expose our skin to sunlight, cholesterol helps convert it to vitamin D to help with immunity and bone health.

Triglycerides are another type of lipid

Most discussions about cholesterol also include triglycerides. While triglycerides aren’t cholesterol, your triglyceride level can greatly impact your cholesterol levels.

Triglycerides are the most common type of fat in the body. If you eat more food than you immediately need, your body creates triglycerides as a way to store calories for later use. So if you often eat more calories than your body burns, you’re likely to have high levels of triglycerides. And if you have high triglycerides, you’re more likely to have high cholesterol.

High levels of cholesterol (and triglycerides) can be dangerous

While cholesterol and triglycerides are important, many people have levels that are too high. If you have high cholesterol (hypercholesterolemia), fatty deposits can harden in arteries in the body. This plaque buildup (atherosclerosis) impacts the flow of blood throughout your body and can lead to a heart attack.

High levels of triglycerides (hypertriglyceridemia) can cause your artery walls to thicken and harden (a condition called arteriosclerosis). Poor blood flow from atherosclerosis or arteriosclerosis can cause serious medical conditions, such as:

• Coronary heart disease – A type of heart disease that can occur when the heart doesn’t receive enough oxygen-rich blood. This can lead to chest pain, shortness of breath and even a heart attack.
• Peripheral artery disease – If there’s plaque buildup in the arteries outside the heart, it can affect blood supply to the legs and arms. This can lead to pain, cold feet and hands, and nonhealing wounds.
• Carotid artery disease – Plaque can also buildup in the blood vessels that supply blood to the brain and head, increasing your chance of a stroke.

Are some types of cholesterol better than others? HDL vs. LDL

Your body makes lipoproteins, which are specific proteins that carry cholesterol and triglycerides throughout your body. These lipoproteins are commonly referred to as “good” cholesterol or “bad” cholesterol. What makes some cholesterol “bad” is that some lipoproteins are more likely to cause plaque buildup.

You want HDL cholesterol proteins to be high

HDL stands for high-density lipoprotein. This is the “good” cholesterol protein, and you want it to be high. In fact, the higher the better. To remember that you want HDL to be high, just think about the first letter. “H” is for high. “H” is also for helpful, as it moves the extra cholesterol in your bloodstream to your liver, so the cholesterol can be removed from your body. Having high levels of HDL may reduce your chance of heart disease. However, it’s still important to pay attention to your LDL levels.

You want LDL cholesterol proteins to be low

LDL stands for low-density lipoprotein. This is the “bad” cholesterol protein that carries cholesterol to your artery walls. You want your LDL levels to be low. Just remember that the “L” stands for low. Generally speaking, the lower the better.

You need some LDL cholesterol protein to carry cholesterol to your body’s cells so that they can function properly. But it’s pretty rare to have LDL cholesterol levels that are too low. If you have too much LDL, it can build up as plaque in your blood vessels, increasing your chance of heart disease and stroke.

You want VLDL cholesterol proteins to be very low

VLDL stands for very low-density lipoprotein. It’s another form of “bad” cholesterol protein. Keep in mind that “VL” means that you want it to be very low.

VLDLs mainly carry triglycerides to tissues in the body that need them. Your body needs a small amount of VLDL to help you gain and store energy, and to manage blood pressure. But most people have more VLDL than they need. High levels of VLDL can lead to plaque buildup on artery walls and heart disease.

A lipid panel measures HDL, LDL and triglycerides

A lipid panel (or lipid profile) is the blood test that measures the lipoproteins and triglycerides in your blood stream. Lipids are measured in milligrams per deciliter (mg/dL). Your test results will show the levels of HDL, LDL, VLDL and triglycerides in your blood. It will also likely include the following:

Total blood cholesterol

This is the total amount of cholesterol protein circulating in your blood. It’s calculated using a specific equation.

Total cholesterol formula: HDL cholesterol + LDL cholesterol + 20% of the triglyceride level.

So, if your levels are 72 HDL, 107 LDL and 120 triglyceride, that equation would look like: 40 + 116 + 24 (which is 20% of 120) = 180 total cholesterol.

Total blood cholesterol that’s under 200 mg/dL is considered healthy. If it’s between 200 and 239 mg/dL it’s considered at risk. If it’s above 240 mg/dL, it’s considered high cholesterol.

Non-HDL cholesterol

Total cholesterol doesn’t tell the whole story. As we learned above, some cholesterol proteins are heart healthy while others are not. Which means it’s possible to have unhealthy levels of “bad” cholesterol even if your total cholesterol is in the target range. High non-HDL cholesterol is generally considered a bigger risk factor for heart disease than high total cholesterol. In fact, the non-HDL number might be the most important measurement since “non-HDL” includes almost all of the cholesterol in your body that is likely to cause plaque and lead to a heart attack, stroke or vascular disease.

Non-HDL cholesterol formula: Total cholesterol - HDL cholesterol = non-HDL cholesterol.

Continuing with the example from above, the calculation would be: 180 (total cholesterol) - 40 (HDL) = 140 non-HDL cholesterol.

Generally speaking, most people should have non-HDL cholesterol that’s less than 130 mg/dL or lower. So you can see from this example, that you can have total cholesterol that’s in the target range while also having “bad” cholesterol that’s considered too high.

Ratio between total cholesterol and HDL

Looking at the ratio between total cholesterol and “good” cholesterol is another way to look at cholesterol levels. You want the “good” to be a higher amount of the total. You should try to keep your cholesterol ratio below 5, but lower numbers are even better.

Cholesterol/HDL ratio formula: Total cholesterol ÷ HDL cholesterol = cholesterol ratio

Going back to our original example, that would be 180 (total cholesterol) ÷ 40 = 4.5.

Normal cholesterol levels by age and gender

Normal cholesterol levels can be different based on your age and sex assigned at birth. However, your doctor may recommend different cholesterol targets if you have heart disease or other risk factors. Your doctor will let you know if you should be concerned about your cholesterol levels and what your next steps may be.

What causes high cholesterol levels?

Cholesterol protein levels are affected by your diet, lifestyle, family history and other medical conditions.

The foods you eat

Your body naturally makes all the cholesterol you need. It’s not necessary to get cholesterol from the food you eat (there’s no recommended daily intake for it), but most people do. Dietary cholesterol comes from animal products, such as meat, poultry and dairy products (plants don’t make cholesterol). Dietary cholesterol is especially high in processed meats like sausages, burgers and hot dogs.

This doesn’t mean that you can’t eat foods from animals, but it’s best to limit the ones that are high in saturated fats. Eating saturated fats – whether from meat, butter or cooking oils – can make your LDL levels go up. But the good news is that eating “good fats” can increase your HDL levels and make a big difference in your non-HDL cholesterol and your cholesterol/HDL ratio.

Low levels of physical activity

Aerobic exercise has many benefits, including boosting HDL levels even without dietary changes. It can also help to lower LDL levels when combined with other changes.

Being overweight

Body fat changes how your body produces and removes cholesterol. Having excess weight slows the removal of cholesterol from your system.

Smoking

Smoking damages blood vessel walls, making it easier for LDL cholesterol proteins to stick to them. It also lowers HDL levels and negatively impacts overall heart health.

Family history and genetics

Your genes can impact the amount and types of LDL in your body in a few ways.

Lipoprotein (a) levels

Lipoprotein (a) is a specific type of LDL that’s passed down through families. It’s estimated that 20% of people have abnormally high lipoprotein (a) levels that put them at higher risk of heart and vascular disease, often at a younger age. This can even be the case if your standard cholesterol levels are normal.

If your lipoprotein (a) levels are very high, your blood may clot more, and the clots may not break down as easily. Lipoprotein (a) also increases inflammation inside blood vessels, which can cause plaque buildup to break open, leading to more blood clots.

If you’re wondering about your lipoprotein (a) levels, ask your doctor about testing next time you have your cholesterol checked. You only need to have lipoprotein (a) tested once, since your levels are unlikely to change during your lifetime. Testing is usually covered by insurance but it’s a good idea to contact member services to make sure.

Familial hypercholesterolemia

High cholesterol can also be caused by a hereditary condition called familial hypercholesterolemia (FH) that increases the amount of LDL in your bloodstream. If high cholesterol is caused by FH, you’ll be unable to control LDL levels through lifestyle choices like exercise and diet. Genetic testing can show whether high cholesterol is caused by FH. If it is, your doctor may provide medications that can help.

Chronic diseases and inflammation

Certain chronic conditions, such as rheumatoid arthritis, lupus, psoriasis and inflammatory bowel disease, can cause excessive inflammation in your body. Chronic inflammation can lower HDL levels and raise LDL levels.

Pregnancy

During pregnancy, it’s normal for cholesterol levels to be higher than normal. This is because your body naturally produces more cholesterol as part of the many hormonal changes which happen during pregnancy. Elevated cholesterol levels are unlikely to cause pregnancy complications or affect fetal development, but you may need additional testing before and after your baby is born.

How often should cholesterol be checked and when to start

Your doctor will let you know when to start regular testing and how often you should get tested. Often, it’s something they’ll bring up at your yearly checkup. If you’re overdue, schedule a preventive care appointment.

All adults aged 20 or older should have their cholesterol checked regularly – at least once every 5 years. Your doctor may recommend that you start testing sooner and get more frequent tests if you have risk factors such as:

• Getting older – Beginning at age 40, it’s likely your doctor will recommend a yearly cholesterol test, but it will depend on your health and other factors.
• Family history – If you have a close family member with a history of heart disease or high cholesterol you may need more frequent testing.
• Increased chance of heart disease – If you have other risk factors for heart disease, such as high blood pressure, smoking or diabetes, your doctor is likely to recommend you get your cholesterol checked at least once a year.
• Pregnancy-related conditions – Your doctor may test your cholesterol if you experience conditions such as gestational hypertension, gestational diabetes or preeclampsia.

Do children need to have their cholesterol tested?

Cholesterol testing generally isn’t recommended for children. But your child’s doctor may recommend they get a cholesterol test between the ages of 9 and 11 if there’s a family history of high cholesterol.

Concerned about cholesterol levels? We can help

High cholesterol levels can seriously impact your health, so it’s important to take steps to manage it. If you think it’s time for a cholesterol checkup, or you’d like help lowering your cholesterol levels, make an appointment with a primary care doctor.

If you’re overdue for a checkup, make a preventive care visit. And if it works for you to fast for 8-12 hours before your appointment, you should be able to get your cholesterol checked on the same day if your doctor thinks it makes sense for you.