Cholesterol is a fat-like substance circulating in the blood. The body needs a certain amount to maintain cell membranes and perform other vital functions, but high levels lead to blocked arteries which can cause a heart attack.

Cholesterol is carried in the blood by two types of protein: low density lipoproteins (LDL) which carry three-quarters of the cholesterol, and high density lipoproteins (HDL).

Total blood cholesterol is measured, and separate measurements are taken of LDL (bad) cholesterol and HDL (good) cholesterol. High LDL and total cholesterol levels increase the risk of a heart attack, as does a low level of HDL (below 0.9 millimoles per litre). Doctors recommend keeping total cholesterol below 5.6 millimoles per litre, ideally around 5.2 millimoles per litre, and your HDL level as high as possible.

High cholesterol levels are often linked to a diet rich in the saturated fat found in animal foods such as beef, butter and whole-fat dairy products and in coconut oil, palm oil and hydrogenated oils used in processed foods. This theory is no longer widely accepted as cholesterol from food is poorly absorbed, and levels of blood cholesterol are affected mainly by the manufacture of cholesterol in the body, but the body's production of cholesterol is certainly stimulated by high intakes of saturated fat.

Excess weight, smoking and lack of exercise also contribute to high cholesterol levels. Genetic predisposition may also be a factor.

Along with dietary changed, Vitamins C and E and some effective herbal compounds can help control your cholesterol levels and reduce the risk of a heart attack. Try taking Vitamins E and C and garlic together. These are safe for long-term use even if you are taking a cholesterol-lowering prescription drug.

Vitamin E does not lower your cholesterol directly, but raises levels of HDL cholesterol and prevents the first step in the build-up of coronary plaque.

Vitamin C boosts the effectiveness of Vitamin E, and is also thought to increase the level of protective HDL cholesterol. Chromium helps to reduce "bad" cholesterol and raise "good" cholesterol in those people with diets high in refined foods. Diets lacking in cholesterol-reducing soluble fibre can benefit from the herb psyllium, or from oat bran, which has a similar action.

Beta-sitosterol can be taken to reduce the absorption of cholesterol from food and from bile discharged by the liver into the intestine. Artichoke extract may prove to be an effective alternative to cholesterol-lowering medications.

If home remedies do not lower your total cholesterol sufficiently within two or three months, you may need to take prescription drugs. Conventional drugs reduce heart attack risk by up to 25%. Take regular exercise to raise your HDL level, and improve your diet by reducing saturated fats. Substitute oily fish for meat, eat high-fibre foods (grains, vegetables and fruit), and use olive oil and mono-unsaturated spreads in place of butter, and include soya protein (available as tofu and soya milk).