Can my HDL be too high?

When high cholesterol is good

There are two main types of cholesterol in the body, and only one is usually considered a risk to heart health.

LDL cholesterol contributes to the fatty buildup that can clog a person’s arteries. When this buildup clogs or narrows the arteries, a heart attack or stroke is more likely to occur. With LDL cholesterol, lower is better.

HDL cholesterol helps remove LDL cholesterol from the blood and transports it to the liver for processing and elimination. A higher HDL number is desirable because it usually signals a lower risk of heart disease.

Some experts also believe HDL may have anti-inflammatory, anticoagulant, antioxidant, and other properties that may offer additional protection from cardiovascular disease.

Lifestyle recommendations for managing cholesterol focus on balancing the types of cholesterol by increasing HDL levels and lowering LDL.

HDL: Is higher always better?

The CDC recommends aiming for HDL levels of 60 mg/dL or above. It is the only measure in the cholesterol test that has a lower rather than an upper limit. Total cholesterol should be below 200 mg/dL, and LDL levels should be less than 100 mg/dL.

Previous research suggests the higher the HDL levels, the more protection a person has from heart disease. However, new evidence is appearing that may challenge this. Some experts are now talking about a U-shaped relationship, in which both very low and very high HDL levels may be harmful.

Some scientists now believe that genetic, lifestyle, and environmental factors may affect the way HDL accumulates in the body and how it behaves, and that some of these effects could be harmful to some people. However, it is still unclear whether this happens and, if so, who it affects and why.

In 2010, some researchers found that people who had recently had a heart attack with high levels of both HDL and a substance called C-reactive protein were at higher risk of having another cardiac event. The liver produces C-reactive protein when inflammation occurs in the body.

Some experts believe that, in certain conditions, HDL particles may take on inflammatory properties rather than protecting a person from inflammation. The authors of a 2019 review note that the protective features of HDL depend not only on how much HDL is present but also on the way it behaves in the body.

A 2018 study with the same lead author suggested that functionality — how HDL works — could be even more significant than circulating HDL levels.

A 2016 research article discusses a rare genetic change that may cause exceptionally high HDL levels. It occurs in a molecule known as SR-BI. The change affects the way HDL works in the body, and it can lead to high levels of HDL and an increased risk of heart disease. The authors note that, in one study, some participants had levels of HDL greater than 95 mg/dL, which is unusual. Some participants with these high levels had this rare genetic feature.

Meanwhile, a 2017 review suggests that the balance of HDL and LDL may play a role. In one of two large studies reviewed, people with “extreme” high or low HDL levels had a higher risk of death than those who had more moderate levels. The authors proposed that optimal levels could be 73 mg/dL in males and 93 mg/dL in females.

While researchers continue to investigate this field, experts still recommend focusing on managing the known risks for cardiovascular disease, including reducing LDL levels.

Finding the right balance

The first step to healthy cholesterol levels is for people to take a test and discuss the results with a doctor, who will also consider their individual risk factors.

The CDC advises most adults to have a cholesterol test every 4–6 years but more often if they have diabetes, heart disease, or a family history of high cholesterol. The CDC also recommends testing for children at some time between the ages of 9 and 11 years and again at 17–21 years.

Cholesterol tests measure the amount of different cholesterols in mg/dL. Most tests show HDL, LDL, and total (serum) cholesterol. To find a total cholesterol score, a doctor will add together a person’s HDL and LDL cholesterol levels and 20% of their triglyceride level.

The CDC lists desirable levels as follows:

However, various factors will affect what is healthy for each person. A doctor will work with the individual to make a plan for maintaining or establishing suitable levels.

Learn more here about cholesterol testing.

Healthy ways to achieve high HDL

For most people, current guidelines recommend maximizing HDL levels, preferably through lifestyle measures. To achieve and maintain moderate levels, experts recommend:

• having regular cholesterol tests
• eating a balanced diet rich in fruits, vegetables, whole grains, and lean protein
• limiting the intake of saturated and trans fats, processed foods, and added salt and sugars
• exercising regularly
• maintaining a moderate weight
• avoiding or quitting tobacco smoking
• limiting alcohol intake
• managing stress, where possible
• getting 7–9 hours sleep at bedtime

Learn about nine ways to boost your HDL cholesterol levels here.

In some cases, a doctor may recommend medication, such as statin therapy.

If a person’s HDL levels are unusually high, a doctor may recommend genetic or other testing to assess their risk of heart disease. Specific medications can address high cholesterol levels due to inherited genetic changes.

If a doctor prescribes medication, the person should take it as directed. If they wish to stop using the drug, they should first speak with a doctor. The person may also need support for other health conditions, such as diabetes or high blood pressure.

What causes high cholesterol?

Summary

Cholesterol is an important indicator of heart disease risk. Doctors recommend aiming for high levels of HDL cholesterol and low levels of LDL cholesterol. HDL cholesterol is beneficial as it helps remove LDL cholesterol from the body.

In some cases, however, a person may develop very high levels of HDL cholesterol, or it may behave in ways that are not beneficial. Scientists are currently investigating how and why this might happen.

Meanwhile, experts continue to recommend focusing on minimizing LDL and maximizing HDL levels, preferably through lifestyle measures but also with medication, where necessary.