Cholesterol

Cholesterol is a type of lipid found in the cell membrane It is also used to make the sex hormones - testosterone, oestrogen, progesterone Cholesterol is synthesised by all cells although 25% of total production takes place in the liver

A diet high in saturated fats or cholesterol causes an increase in cholesterol levels in the blood

High density lipoproteins (HDL) transports excess cholesterol from the body cells to the liver for elimination This prevents the accumulation of cholesterol in the blood

Low density lipoproteins (LDL) transports cholesterol to body cells Most cells have LDL receptors that take LDL into the cell where it releases cholesterol Once a cell has sufficient cholesterol a negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates in the blood where it may deposit cholesterol in the arteries forming atheromas

A higher ratio of HDL to LDL will result in lower blood cholesterol and a reduced chance of atherosclerosis Regular physical activity tends to raise HDL levels. Dietary changes aim to reduce the levels of total fat in the diet and to replace saturated with unsaturated fats

Drugs such as statins reduce blood cholesterol levels by inhibiting the synthesis of cholesterol by liver cells