High Density Lipoprotein

Cholesterol is found in all cells. It is needed for many body functions. Two types of cholesterol are HDL and LDL. HDL is a “good” cholesterol that removes LDL (bad) cholesterol from the bloodstream.

High-density lipoprotein (HDL) is one of the five major fat and protein particles (lipoproteins) whose role it is to enable blood fats (lipids), such as cholesterol and triglycerides, to be transported within the water-based bloodstream.

HDL is a class of heterogeneous lipoproteins containing approximately equal amounts of lipid and protein. HDL particles are characterized by high density (more 1.063 g/mL) and small size (Stoke’s diameter 5 to 17 nm).

The various HDL subclasses vary in quantitative and qualitative content of lipids, apolipoproteins, enzymes, and lipid transfer proteins, resulting in differences in shape, density, size, charge, and antigenicity.

In a normal healthy individual, HDL carries about a quarter of the total amount of cholesterol in the blood, whereas most of the remainder is carried in LDL (low density lipoprotein) “bad cholesterol” particles.

HDL is important for the synthesis of steroid hormones but it is better known for its protective role against cardiovascular disease. A low HDL is thought to speed up the rate at which arteries fur up.

HDL (good) cholesterol protects against heart disease, so for HDL, higher numbers are better. A level less than 40 mg/dL is low and is considered a major risk factor because it increases the risk for developing heart disease. HDL levels of 60 mg/dL or more help to lower the risk for heart disease.

A variety of things can affect cholesterol levels: Diet, Weight, Physical Activity. Low HDL among others due to: Insulin resistance, Familial Combined Hyperlipidaemia (FCH), Tangier disease, Medicines including beta blockers, thiazide diuretics, androgens, progestogens and anabolic steroids.
High Density Lipoprotein 

Cholesterol and heart disease

Cholesterol is a fat-like substance, found in the blood stream and also in bodily organs and nerve fibres. Cholesterol is needed in the body to insulate nerves, make cell membranes and produce certain hormones, and it is an important lipid in some membranes.

Cholesterol can be both good and bad. High-density lipoprotein (HDL) is good cholesterol and low-density lipoprotein (LDL) is bad cholesterol.

*High density lipoprotein, or HDL, which also is called the “good” cholesterol because it takes cholesterol from tissues to the liver, which removes it from the body.

*Low density lipoprotein, or LDL, which also is called the “bad” cholesterol because it carries cholesterol to tissues, including the arteries. It can build up in the arteries and form fatty, waxy deposits called plaques. It will increase the risk of getting heart disease.

Excess cholesterol in the bloodstream can form plaque (a thick, hard deposit) in artery walls. The cholesterol or plaque build-up causes arteries to become thicker, harder and less flexible, slowing down and sometimes blocking blood flow to the heart.

High LDL cholesterol can damage the arteries and increase the risk of heart attacks (myocardial infarction - MI), chest pain (angina), narrowing of the blood vessels (peripheral artery disease) and stroke – as a group these are called cardio vascular disease (CVD).

High cholesterol levels in blood are mainly caused by eating foods high in saturated fats and trans-fats, and not including foods with unsaturated fats and with fibre.

Saturated fat and cholesterol in the food can make blood cholesterol level go up. Saturated fat is the main culprit, but cholesterol in foods also matters. Reducing the amount of saturated fat and cholesterol in the diet helps lower blood cholesterol level.

Example of foods containing saturated fats and trans-fats –such as fatty meats, full-fat dairy products, butter, coconut oil, palm oil and most deep-fried takeaway foods and commercially baked products, such as pies, biscuits, buns and pastries. Food high in trans-fats include most commercially baked products and deep-fried takeaway foods.

Cholesterol lowering is important for everyone–younger, middle age, and older adults; women and men; and people with or without heart disease.
Cholesterol and heart disease