The body uses cholesterol to allow proteins to move more easily through cell membranes and also for the manufacturing of steroid hormones such as cortisol, testosterone and estrogen. Cholesterol can also contribute to the development of coronary artery disease and strokes due to its ability to narrow arteries. The liver is involved in regulating the levels of cholesterol, including one form of cholesterol known as high density lipoproteins.
Liver and Cholesterol
The liver has an important role in regulating cholesterol. It is able to synthesize cholesterol, Washington University explains, and it also secretes cholesterol from the body via bile salts. The liver is also responsible for making lipoproteins, which are a combination of cholesterol, proteins and other lipids. Lipoproteins are used to transport cholesterol and other lipids throughout the body.
Lipoprotein Types
There are four kinds of lipoproteins made by the liver. Two of them, known as chylomicrons and very low-density lipoproteins, do not have a significant role in cholesterol transport. Another kind of lipoprotein, known as low-density lipoprotein or LDL is used to deliver cholesterol to cells within the body. This type of lipoprotein is also known as "bad" cholesterol because it can transport cholesterol to the walls of the arteries. High density lipoprotein or HDL, on the other hand, is considered to be "good" cholesterol because it scavenges excess cholesterol from the blood and delivers it to the liver, Washington University states. As a result, HDL cholesterol can help protect the body from atherosclerosis.
HDL Levels
HDL is normally measured as part of a lipid profile, which is a routine blood test which measures the concentration of LDL, HDL and triglycerides in the blood, LabTestsOnline explains. Men normally have between 40 and 50 mg of HDL per dL of blood, and the normal range of HDL for women is between 50 and 59 mg per dL of blood. HDL levels higher than 60 mg per dL are considered to be helpful for preventing heart disease. Numbers lower than normal are classified as a risk factor for cardiovascular problems such as a heart attack or stroke.
Causes of Low HDL
The thing that most impacts HDL levels is lifestyle, the Mayo Clinic reports. Smoking can decrease a person's HDL levels by up to 10 percent. Being overweight and eating foods which are high in fat, particularly trans and saturated fats can also depress HDL levels. A lack of physical activity can also cause HDL levels to be low.
Increasing HDL Levels
The simplest way to increase HDL levels is to identify lifestyle factors which are causing the decreased HDL concentrations and adopting a lifestyle which promotes increased HDL levels. There are a number of medications, including niacin, statins and fibrates which can be used to increase HDL levels. Omega-3 fatty acids, a type of unsaturated fat found in leafy greens, soy products and some fish, may also help boost the amount of HDL present in the blood.
