High-density lipoprotein (HDL) cholesterol is often referred to as the “good” cholesterol because it helps remove other, more harmful forms of cholesterol from your blood. It’s usually thought that the higher your HDL levels are, the better. In most people, this is true. But some research shows that high HDL can actually be harmful in certain people.
Typically, doctors recommend an HDL level of 60 milligrams per deciliter (mg/dL) of blood or higher. HDL that falls within the range of 40 to 59 mg/dL is normal, but could be higher. Having HDL under 40 mg/dL increases your risk of developing heart disease.
Research published by the journal Arteriosclerosis, Thrombosis, and Vascular Biology found that people with high levels of C-reactive proteins after having had a heart attack may process high HDL negatively. C-reactive proteins are produced by your liver in response to high levels of inflammation in your body. Instead of acting as a protective factor in heart health, high HDL levels in these people could instead increase the risk of heart disease.
While your levels may still be in the normal range, your body may process HDL differently if you have this type of inflammation. The study looked at blood drawn from 767 nondiabetic people who had recently had a heart attack. They used the data to predict outcomes for the study participants and found that those with high levels of HDL and C-reactive proteins were a particularly high-risk group for heart disease.
Ultimately, more research needs to be done to determine the risks of high HDL in this particular group of people.
Other conditions and medications associated with high HDL
High HDL is also linked to other conditions, including:
- thyroid disorders
- inflammatory diseases
- alcohol consumption
Sometimes cholesterol-controlling medications can also raise HDL levels. These are usually taken to lower LDL, triglyceride, and total cholesterol levels. Medication types that have been linked to increased HDL levels include:
- bile acid sequestrants, which decrease fat absorption from the foods you eat
- cholesterol absorption inhibitors
- omega-3 fatty acid supplements, which lower triglycerides in the blood, but also increase HDL cholesterol
- statins, which block the liver from creating more cholesterol
Increasing HDL levels is usually a positive side effect in people who have low HDL levels as in most cases, it decreases their risk of developing cardiovascular disease.
A blood test can determine your HDL levels. In addition to an HDL test, your doctor will also look for LDL and triglyceride levels as a part of an overall lipid profile. Your total levels will also be measured. Results usually take just a few days to process.
Certain factors can influence the results of your test. Talk to your doctor if:
- you’ve recently been ill
- you’re pregnant
- you’ve given birth in the last six weeks
- you hadn’t been fasting before the test
- you’re more stressed than usual
- you’ve recently had a heart attack
All these factors can lead to inaccurate measurements of HDL in the blood. You may need to wait several weeks before taking a cholesterol test to make sure the results are correct.
In most people, high HDL is not harmful, so it doesn’t necessarily require treatment. The action plan depends largely on how high your levels are, as well as your overall medical history. Your doctor can help determine whether you need to actively lower HDL levels or not.
Your overall cholesterol levels may be decreased by:
- not smoking
- drinking alcohol in moderate amounts only (or not at all)
- getting moderate exercise
- reducing saturated fats in your diet
- managing underlying health conditions, such as thyroid diseases
The American Heart Association recommends that everyone over the age of 20 gets a cholesterol test every four to six years. You may need to test more frequently if you have risk factors for high cholesterol, such as family history.
More research is needed to further understand how high HDL can be harmful in certain people. If you have a personal or family history of either high cholesterol levels or C-reactive proteins, talk to your doctor about steps you can take to regularly monitor your HDL levels.
Q&A: Heart attack and HDL levels