Cholesterol is a waxy, fat-like substance carried in the blood. Most of our cholesterol is produced naturally in the liver, but some comes from our diet. Cholesterol is used by the body to produce bile, the digestive juice that helps us process fats. It's also used in the manufacture of cell membranes and hormones such as oestrogen, and to process vitamin D.
Our bodies are efficient at balancing the level of cholesterol in the blood: the more we have in our diet, the less our liver produces. But sometimes cholesterol can build up in the blood, increasing the risk of heart disease.
Cholesterol is carried around the body by substances in the blood called lipoproteins. There are two types of these: low-density lipoproteins (LDL) and high-density lipoproteins (HDL).
LDL cholesterol (or 'bad' cholesterol) can form fatty deposits in the blood vessel wall. These can narrow the arteries causing atherosclerosis, a major cause of heart disease. HDL cholesterol (or 'good' cholesterol) removes the excess cholesterol left by the LDL type and returns it to the liver for disposal. Our diet should favour the production of HDL cholesterol, and discourage that of LDL cholesterol.
Blood cholesterol is measured in millimoles (mmol) per litre. Less than 5 mmol/litre is considered healthy, and anything above 6 mmol/litre is high. Your doctor can measure your cholesterol level with a blood test. You can buy home-testing kits, but they're less accurate.
The amount of good or bad cholesterol in the body is influenced by the type of fats in the diet. There are three types of dietary fat: saturated, mono-unsaturated and poly-unsaturated.
Saturated fat, in butter, hard fats and animal products, tends to raise both total cholesterol and the level of bad cholesterol in the blood. Mono-unsaturated fat, in olive oil and nuts, tends to reduce the level of bad cholesterol. Poly-unsaturated fat generally promotes the formation of good cholesterol and reduces the formation of bad cholesterol.
Good sources include fish oils and vegetable oils. We should eat fewer fats that are hard at room temperature and more of those that are liquid.
Cut down the amount of fat in your diet, particularly your saturated fat intake. Replace some saturated fat (eg butter) with unsaturated fat, such as olive oil. This is better than just cutting out foods high in saturated fat as it's the proportion of 'good' cholesterol to 'bad' that makes the biggest difference to health.
Eating soya beans, foods rich in soluble fibre and foods containing plant substances called sterols and stanols may help to control blood cholesterol. Oats, fruit and vegetables are good sources of soluble fibre; nuts and some cholesterol-lowering spreads and drinks are rich in sterols or stanols.
Other steps, such as giving up smoking, losing excess weight and taking regular exercise, can also help.
- Eat starchy fibre-rich foods e.g. rice, pasta, fruit and vegetables.
- Choose lean cuts of meat and poultry. Remove the skin from chicken.
- Choose reduced-fat dairy products such as skimmed or semi-skimmed milk. Use fat free fromage frais or Greek yogurt in place of cream.
- Cook with strongly flavoured cheese (you'll need less, so less fat).
- Cook with olive oil or sunflower oil rather than lard or butter.
- Try steaming, microwaving and grilling rather than frying. If stir-frying, use an oil spray and non-stick frying or griddle pans.
- Snack on fresh or dried fruit rather than crisps or biscuits.
- Waitrose offers healthier alternatives to your favourites that are either lower in fat, saturated fat, sugar or calories. Look out for the distinctive black and white band on the front of pack. For more information on balanced diets, visit Balancing your diet
- Keep your fat intake to a healthy level. The Guideline Daily Amount (GDA) for fat is 70g (women) and 95g (men). For saturated fat it's 20g (women) and 30g (men). All Waitrose prepacked products carry a nutrition label detailing the amount of fat and saturated fat per 100g. The amount per serving is also highlighted on many products.
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