High blood cholesterol levels are a significant risk factor for heart disease and stroke. Diets that include food low in saturated fats and dietary cholesterol can reduce “bad” cholesterol (LDL) levels and increase “good” cholesterol (HDL) levels.
Cholesterol is a white, waxy substance that is circulated in the blood. High blood cholesterol levels are known medically as hypercholesterolaemia or hyperlipidaemia.
Cholesterol is essential for life. It helps to build cell walls and is used in the manufacture of some hormones. The liver produces approximately 70-80% of the cholesterol circulating in the blood, while the remaining 20-30% is derived from the food we eat.
When there is more cholesterol circulating in the blood than the body needs, it can deposit onto the artery walls, eventually leading to narrowing and hardening of the arteries. This process is known as atherosclerosis and increases the risk of heart disease and stroke. This risk is compounded when other risk factors such as high blood pressure and a family history of heart disease are also present.
High levels of cholesterol in the blood may be due to eating a diet too high in saturated fat and/or by having a genetic susceptibility to high cholesterol (familial hypercholesterolaemia). Cholesterol levels can also be influenced by medical conditions such as diabetes and liver or thyroid disorders. It is estimated that 90% of adult New Zealanders would benefit by lowering their cholesterol levels.
Dietary cholesterol is present in animal foods – mainly in dairy products, meat, egg yolks and offal – and shellfish. It is not present in plant foods. Eating a diet high in saturated fat stimulates the liver to produce more cholesterol. Both cholesterol-containing and non cholesterol-containing foods can have high levels of saturated fat. Therefore the saturated fat content of food, as well as the cholesterol content of the food, can influence blood cholesterol levels.
Treatment for High Cholesterol
Treatment aims to decrease the total cholesterol level by decreasing LDL cholesterol levels and increasing HDL cholesterol levels. Initially diet and lifestyle changes may be tried.
Dietary changes include:
- Reducing the total amount of fat in the diet, especially saturated fats (found mainly in animal products such as fatty meat, butter, high fat milk, cream and dripping)
- Eating generous amounts of fruit, vegetables and fibre. It is thought that certain types of fibre such as legumes, oats, fresh fruit and vegetables can reduce cholesterol levels.
- Eating complex carbohydrates such as cereals, root vegetables (kumara, potatoes) instead of fat.
Lifestyle changes include:
- Exercising regularly
- Not smoking
- Maintaining a healthy body weight
- Limiting alcohol intake.
LDL cholesterol levels are best decreased by reducing the intake of saturated fat, while HDL cholesterol levels are best increased by regular exercise (at least 30 minutes duration three times per week), substituting saturated / polyunsaturated fats with monounsaturated fat, and maintaining a healthy weight. Triglyceride levels are best reduced by eating less sugar-containing foods, limiting alcohol intake and by reducing the intake of total fat.
Tips For Lowering Cholesterol
- Set realistic goals and make changes one at a time
- Keep a food diary in order to become more aware of food habits and note areas where changes are required
- Get the support of family and friends
- Change cooking methods to avoid adding fat. Steam, microwave, poach, grill or bake food rather than fry or roast. Use non-stick sprays on cookware rather than oil
- Remove the skin from poultry and trim fat off meat before cooking
- Eat more fish and chicken instead of red meat
- Polyunsaturated and monounsaturated fats should be used in place of saturated fats (eg: olive oil instead of butter). Be wary of vegetable products that are high in saturated fat or transfatty acids, such as hydrogenated vegetable oil and coconut cream
- Avoid prepared food, snacks and meals unless total and type of fat content are known
- Restrict eggs to two or three a week. Use only the egg white instead of the whole egg in cooking
- Try lemon juice, vinegar, or low-fat dressing instead of oily dressings or mayonnaise
- Choose low fat dairy products eg: cottage cheese, skim milk, low-fat yoghurt, instead of higher fat dairy products
- Eat plenty of fresh fruit and vegetables as these are high in fibre and contain no cholesterol and very little or no fat.