Cholesterol is a type of fat made by the body. It is essential for good health and is found in every cell in the body. A high cholesterol level in the blood is associated with an increased risk of heart disease and stroke. High cholesterol causes blood vessels to become narrowed with fatty deposits called plaques. This can result in heart attacks, strokes and blood vessel problems.
Cholesterol is transported around the body in the blood attached to a protein. This combination of fat and protein is called a lipoprotein. Lipoproteins can be high density (HDL), low density (LDL) or very low density (VLDL), depending on how much protein there is in relation to fat.
HDL helps prevent cholesterol deposits building up in the arteries. Having low levels of HDL in the blood is associated with an increased risk of CVD. So HDL is sometimes referred to as "good cholesterol".
If the total cholesterol (TC) level is too high, this is one risk factor for health problems. However, it's important to consider the relative amounts of HDL and LDL. This is often referred to as the TC: HDL ratio. A high level of HDL and a low level of LDL is desirable.
Triglycerides are a different type of fat. These come from fats in your food. Energy that is eaten and not used immediately is converted into triglycerides and transported to fat cells for storage. This is an important source of stored energy. A raised level of blood triglycerides together with high LDL can increase the risk of heart disease, particularly in people with diabetes.
Factors that may contribute to high blood cholesterol is a diet high in saturated fat and so high in cholesterol. Lack of exercise may increase LDL ("bad") cholesterol and decrease HDL ("good") cholesterol. Also, family history, being overweight, which may increase LDL cholesterol and decrease HDL cholesterol, age, drinking more than the recommended amount of alcohol (ie more than three to four units per day for men and two to three units per day for women) contribute to high cholesterol.
A small amount of cholesterol comes directly from your diet, the majority is produced by your liver. However, if your diet is high in saturated fats and cholesterol this can cause your liver to produce more LDL cholesterol. The amount that diet influences cholesterol levels varies from person to person.
The main aim of lowering cholesterol is to reduce the risk of heart disease. There are two ways to help lower high cholesterol. The first is with simple lifestyle changes including changing diet, managing weight and increasing exercise. The second is to combine lifestyle changes with cholesterol-lowering medicines.
Your diet should be low in saturated fats in particular, and low in fat overall. Biscuits, cakes, pastries, red meat, hard cheese, butter and foods containing coconut or palm oil all tend to be high in saturated fats, so cut down on these foods.
Large amounts of cholesterol are found in a few foods, including eggs, offal such as liver and kidneys, and prawns. However, if you're already eating a balanced diet, you don't need to cut down on these foods unless your GP or dietitian have advised you to.
It's also important to eat plenty of fibre, especially soluble fibre, which is thought to lower cholesterol. It's found in fruits and vegetables, beans and oats. Aim to eat at least five portions of fruit and vegetables each day. Cholesterol-lowering medicines are considered for people who already have CVD, or are at high risk of getting it because they have other risk factors.
