7 Causes of Low HDL Cholesterol Levels

High-density lipoprotein (HDL) cholesterol that is too low can increase your risk of heart disease and stroke, especially when your low-density lipoprotein (LDL) cholesterol is too high. That's because HDL protects the arteries by removing cholesterol and taking it to the liver for processing and elimination.

Some people have a genetic risk for cholesterol problems, but you can limit some of the risk factors when your "good" HDL is too low. Lifestyle changes including diet, exercise, and not smoking can help to improve your levels. Medication can help to control your LDL lipoproteins, too.

There are seven key factors linked specifically to HDL deficiency.

Genetic Mutations

Sometimes, a very low HDL count is caused by genes that run in families. These include conditions like Tangier’s disease, caused by mutations in the ABCA1 gene, and another called familial hypoalphalipoproteinemia, caused by mutations of the APOA1, ABCA1, or LCAT genes.

Excess Weight

If you are overweight or diagnosed with obesity, a type of blood fat called triglycerides will increase. HDL is composed of triglycerides and, when triglyceride levels are high, HDL will undergo changes that cause it to break down faster, leading to a lower count.

Losing 5% of your body weight is a reasonable short-term goal to address overweight and obesity. Over the longer term, losing 15% of your body weight and remaining at this weight is considered a good result. Some studies note that these goals vary with the individual.

Working with a healthcare provider, personal trainer, and/or nutritionist can ensure that the weight-loss plan is safe and effective.

Poor Diet

A diet high in refined carbohydrates (such as white bread and sugar) causes the liver to produce more triglycerides, resulting in a drop in HDL. Some foods you eat are also rich in triglycerides, including fried foods, processed foods, red meat, high-fat dairy, and margarine.

To counter this, limit your intake of refined carbs and saturated fats found in animal-derived foods. Instead, substitute with whole grains and healthier monounsaturated and polyunsaturated fats. These are found in plant-based foods.

Inactivity

A lack of exercise is associated with the buildup of fatty deposits in arteries called atherosclerosis. Exercise improves HDL's ability to scoop up these fatty deposits and move them to the liver for disposal (a process known as cholesterol efflux).

Aerobic exercise is known to increase HDL levels. Studies have shown that the duration of aerobic exercise, as opposed to intensity, is the main factor associated with benefits but more study is needed to understand why.

To counter this, try to get 150 minutes of moderate intensity exercise or 75 minutes of aerobic exercise each week. A combination of the two can include moderate dancing or brisk walking, along with the more intense running, faster bicycling, or swimming laps.

Smoking

The chemicals in tobacco smoke can lower HDL levels in different ways, and research studies confirm the effects of smoking on HDL. However, the precise reasons are not fully understood.

Some studies point to interaction with proteins called cholesterol ester transfer protein (CETP) and fats called lecithin, both of which are needed to build HDL, but the results are mixed. Smoking also appears to affect liver function that's important to cholesterol and triglyceride levels.

Quitting cigarettes can be hard, but you can succeed. Speak with your healthcare provider about smoking cession aids, many of which are fully covered by health insurance under the Affordable Care Act.

Uncontrolled Diabetes

Low levels of HDL and the risk of type 2 diabetes are closely linked, although more study is needed to fully understand why. Insulin resistance, for example, is associated with both low HDL levels and the development of type 2 diabetes.

Some studies point to the role of apolipoprotein A1 (ApoA1), which is needed to produce HDL, because it appears to influence the development of diabetes and other metabolic diseases. The low HDL levels seen in people with chronic kidney disease also may be related to ApoA1.

Researchers are even looking at ways that treatments based on ApoA1 levels can be used to manage blood sugar in type 2 diabetes. It's essential to avoid poorly controlled diabetes, so speak with your healthcare provider about any needed changes to your diet, exercise, or diabetes medication.

Medicines

Certain medications are known to lower HDL levels. Some of these are used to treat heart disease, while others affect hormones that can indirectly affect the production of lipoproteins.

These include:

• Beta-blockers: Most often used to treat irregular heartbeats and angina
• Thiazide diuretics: A type of "water pill" used to treat high blood pressure
• Androgens: Male hormones, most specifically testosterone
• Progesterone: Commonly used in hormonal birth control
• Anabolic steroids: Used for rapid muscle growth and bodybuilding

Do not stop any prescribed drug or alter the dose without first speaking with your healthcare provider.

Optimal HDL Levels

Cholesterol levels are checked with a simple blood test called a lipid panel. HDL counts are described in milligrams per deciliter of blood (mg/dL).

Optimal HDL levels can vary by a person's age and/or assigned sex at birth, as follows:

• People 19 and under: Greater than 45 mg/dL
• Males over 20: Greater than 40 mg/dL
• Females over 20: Greater than 50 mg/dL

Anything below these values is considered HDL deficiency. While an HDL count is just one factor in overall health, it can direct actions to reduce risk, including smoking cessation, changes in diet, and medications called statins used to reduce "bad" cholesterol.

Summary

HDL is the "good" cholesterol that helps remove cholesterol from your arteries. Higher levels are considered better for heart health. Normal levels are at least 40 mg/dL for adult males and 50 mg/dL for adult females.

Your HDL level is important, but your healthcare provider will likely focus less on the number and more on what it means for your overall health. That may mean lifestyle changes, which can put you in control of your weight, diet, smoking habits, and other contributing factors.

Talk with your healthcare provider about how often you should have your cholesterol checked (it's a common test with your annual physical) and what your results mean in terms of any treatment.

Cholesterol Healthcare Provider Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

Download PDF

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