Cholesterol is a waxy, fat-like substance that's naturally produced in your body, primarily by your liver. It's in all the cells in your body and is essential to the production of hormones, vitamin D, and bile, which helps you digest your food. It is carried around in the blood by lipoproteins. We need a small amount of blood cholesterol because the body uses it to:
How cholesterol moves around the body?
- Build the structure of cell membranes
- Make hormones like oestrogen, testosterone and adrenal hormones
- Help your metabolism work efficiently, for example, cholesterol is essential for your body to produce vitamin D
- Produce bile acids, which help the body digest fat and absorb important nutrients
Cholesterol is a white, insoluble and waxy substance. It is carried around the body by two key transport systems in the blood, which include:
What are safe blood cholesterol levels?
- Low-density lipoprotein (LDL) cholesterol: Carries most of the cholesterol that is delivered to cells. It is called the ‘bad’ cholesterol because when its level in the bloodstream is high, it can clog up your arteries.
- High-density lipoprotein (HDL) cholesterol: It is called the ‘good’ cholesterol, because it helps remove excess cholesterol out of the cells, including cells in the arteries.
Doctors recommend that cholesterol levels
should be no higher than 5.5 mmol per litre if there are no other risk factors present. If there are other cardiovascular risk factors such as smoking and high blood pressure or pre-existing cardiovascular (heart) disease, then the aim for the LDL levels
would be less than 2 mmol/l. Unfortunately, a major portion of the world’s population has a blood cholesterol level above 5 mmol/l which makes it a major health concern.
What are the effects of high cholesterol levels?
The liver is the main processing centre for cholesterol and dietary fat. When we eat animal fats, the liver transports the fat, together with cholesterol in the form of lipoproteins, into our bloodstream.
Too much cholesterol circulating within LDL in our bloodstream leads to fatty deposits developing in the arteries. This causes the vessels to narrow and they can eventually become blocked. This can lead to heart disease
You don’t need to eat foods that contain cholesterol. Your body can produce all the cholesterol it needs. High-cholesterol foods are often foods that are also high in saturated fats. These foods should be limited in a healthy diet
The cholesterol in your diet comes mainly from eggs and from animal products that are rich in fat such as meats and full fat dairy foods. All foods from animals contain some cholesterol. Foods from plants do not contain cholesterol.
How to avoid saturated fats?
The best way to have healthy levels of cholesterol in your diet is to limit foods high in saturated fats. Try to avoid:
Tips to avoid high cholesterol
- Fatty meats
- Processed meats like salami and sausages
- Snack foods like chips
- Most takeaway foods, especially deep-fried foods
- Cakes, biscuits and pastries
The most important thing you can do to reduce your cholesterol level is to maintain a healthy lifestyle. You should try to:
- Increase the amount and variety of fresh fruit, vegetables and wholegrain foods you have each day.
- Choose low or reduced-fat milk, yoghurt and other dairy products or have ‘added calcium’ soy drinks.
- Choose lean meat (meat trimmed of fat or labelled as ‘heart smart’).
- Limit fatty meats, including sausages and salami, and choose leaner sandwich meats like cooked lean chicken.
- Have fish (fresh or canned) at least twice a week.
- Replace butter and dairy blends with polyunsaturated margarines.
- Include foods in your diet that are rich in soluble fibre and healthy fats, such as nuts, legumes and seeds.
- Limit cheese and ice cream to twice a week
Other ‘storage’ fats that are transported in blood lipoproteins include triglycerides
. When present in high concentrations in the blood, this fat is also a risk for heart attack
. Some foods will affect the cholesterol level or the triglyceride level and some will affect both.
Some people believe that cutting out dairy foods altogether is the safest option, but this isn’t true. Dairy foods are an important part of your daily diet and contribute many essential nutrients, especially calcium
. Vegans, however, can obtain calcium from many other sources including soy milk.
Foods that may lower high cholesterol levels
LDL cholesterol can be lowered by polyunsaturated oil (for example, sunflower or safflower oil). Eating oats and legumes can lower LDL cholesterol. Food components like saponins (found in chickpeas, alfalfa sprouts and other foods) and sulphur compounds (like allicin - found in garlic and onions) may also have a positive effect in lowering cholesterol levels.
Lifestyle tips to reduce high cholesterol
Changing some of your lifestyle habits may also help to reduce your cholesterol and triglyceride levels. Suggestions include:
- Cease alcohol consumption or reduce your alcohol intake to no more than one or two drinks a day. Avoid binge drinking. This may help lower your triglyceride levels.
- Don’t smoke. Smoking increases the ability of LDL cholesterol to get into artery cells and cause damage.
- Exercise regularly (for example, at least 30 minutes of brisk walking daily). Exercise increases HDL levels while reducing LDL and triglyceride levels in the body.
- Lose any excess body fat. Being overweight may contribute to raised blood triglyceride and LDL levels.
- Control your blood sugar levels if you have diabetes. High blood sugars are linked to an increased risk of atherosclerosis (‘hardening of the arteries’), heart attacks and strokes.