What is hdl cholesterol?

"The NHS recommends that hdl cholesterol levels for an adult should be 1 mmol/L (millimoles per litre) or more. Adopting healthy lifestyle choices will help you to maintain this level of hdl cholesterol."

Dr Louisa Draper

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Related Medications

Simvastatin

Lipitor / Atorvastatin

Cholesterol is a type of lipid called a sterol, that is largely produced by your liver. Cholesterol has important functions in hormone production and digestion. It is used by cells all over your body, transported to where it is needed via your blood. However, cholesterol is insoluble in water, so it cannot travel in the bloodstream unaided.

Lipoproteins are molecules formed of lipid (fat) and protein that attach to cholesterol and help carry it around the body. There are several different types of lipoproteins. Hdl, which stands for high density lipoprotein, is one of those that form attachments to cholesterol.

Statins

Why is it known as ‘good’ cholesterol?

Although cholesterol is an essential fat, having too much cholesterol in the blood can be harmful to your health. Another type of cholesterol, low-density lipoprotein cholesterol (ldl cholesterol), is considered ‘bad’ for you, as it increases your risk of developing heart disease.

Hdl cholesterol is known as ‘good’ cholesterol because it helps to control your levels of ‘bad’ cholesterol and maintain healthy overall cholesterol levels. It works by collecting the excess ldl cholesterol from your bloodstream and surrounding tissues and transporting it back to the liver, where is it broken down.

Hdl also helps to maintain healthy blood vessels. Damage to the inner walls (the endothelium) is the first step in atherosclerosis, the narrowing and hardening of blood vessels due to deposits of plaque. Hdl has anti-inflammatory properties and helps to remove plaque build-up from the walls of your blood vessels, keeping them clean and healthy. Therefore, in general, people with a high level of hdl cholesterol have a lower risk of developing heart disease.

How can you boost hdl cholesterol?

Although having high cholesterol levels is generally considered bad, it depends on what type of cholesterol it is. The ratio of ldl cholesterol to hdl cholesterol is an important factor in maintaining a healthy heart.

Ideally, you want to increase your levels of hdl cholesterol while decreasing levels of ldl cholesterol.

The NHS recommends that hdl cholesterol levels for an adult should be 1 mmol/L (millimoles per litre) or more. Adopting healthy lifestyle choices will help you to maintain this level of hdl cholesterol. It is recommended that you:

Quit smoking. Smoking encourages cholesterol to collect in your blood vessels, making it harder for the hdl to remove it.
Exercise more. Thirty minutes of brisk aerobic exercise (anything that increases your heart rate) five times a week can boost your hdl cholesterol levels within a couple of months.
Stay at a healthy weight. This can help to raise your hdl and lower your ldl cholesterol levels.

Incorporating these hdl-friendly foods into your diet will help to increase hdl levels:

Increase unsaturated fats. These are found in many vegetable oils and nuts.
Beans and legumes, such as chickpeas and lentils.
Whole grains, such as oats, barley and quinoa.
Fatty fish. Fish such as mackerel and salmon contain omega-3 fatty acids, which have been shown to improve the ratio of good to bad cholesterol. You may also consider taking fish oil supplements.
Flaxseeds and flaxseed oil also contain high levels of omega-3 fatty acids.
Moderate alcohol consumption (one to two drinks per day) has been linked to increased hdl cholesterol levels.
Avoid foods that contain saturated fats (from red meat, dairy, eggs) and trans fats (found in processed foods), as these increase your bad ldl cholesterol levels and can cause damage to your blood vessels.

Some medicines, such as fibrates and statins, which can be prescribed by your doctor to decrease ldl levels, may also help to boost your hdl levels. Your doctor may also prescribe niacin, also known as nicotinic acid (a B vitamin), as it can raise hdl cholesterol by 30%. However, it is associated with some serious side effects, so it isn’t suitable for everyone.

Can hdl cholesterol have a negative impact?

Traditionally, high levels of ‘good’ hdl cholesterol are seen as beneficial because it can pump ‘bad’ cholesterol out of cells (known as cholesterol efflux capacity), and has anti-inflammatory properties. However, hdl particles differ in their size and function, and research has found that not all hdl cholesterol is equally able to perform these tasks.

Therefore, it doesn’t necessarily matter how much hdl cholesterol you have, but more that it is able to function correctly. For a certain group of patients, hdl cholesterol provides no benefit, and may even be harmful.

If you suffer from cardiovascular disease or other diseases linked with inflammation, such as diabetes or rheumatoid arthritis, you may have a different make-up of hdl molecules that do not act correctly, which can actually increase the inflammatory response. If this response is combined with other risk factors, including certain genetics or a family history of heart disease, having high levels of hdl cholesterol can be harmful and may put you into a high-risk group for heart problems.