We hear a lot about cholesterol in the news and on TV, but how many of us actually understand what it is? Today we'll be taking an in-depth look at cholesterol and its function within the body. We'll also be discussing the dangers and causes of high cholesterol, before moving on to the lifestyle choices we can make to protect ourselves.
What is Cholesterol?
Heart UK defines cholesterol as:
A fatty substance which is made in the liver. It's found in some foods too."
Despite what you might think, we all need some cholesterol in our bodies. It has several important roles to play.
- It forms part of the outer layer of all the body's cells.
- The body needs it to make Vitamin D and several hormones which support bones, teeth, and muscles.
- It also helps the body to make bile, which aids digestion.
Where Does Cholesterol Come From?
Our livers make around 80% of the cholesterol in our bodies, with the rest coming from the food we eat. The liver packages it up into parcels called lipoproteins. The blood then carries these lipoproteins (containing cholesterol) around the body to wherever they are needed.
There are several different kinds of lipoproteins. The two main types are:
- High-Density Lipoprotein (HDL) - These carry cholesterol away from the cells and back to your liver. The liver then breaks it down and removes it from the body as waste. If you hear someone talking about 'good cholesterol' they're referring to HDL cholesterol.
- Low-Density Lipoprotein (LDL) - These carry cholesterol to the cells that need it. However, if there is too much LDL cholesterol for the cells to use, it can build up in the artery walls leading to serious health risks. Therefore, some people call this 'bad cholesterol'.
You're likely aware that high cholesterol is bad for your health. However, high cholesterol levels don't cause symptoms. You'll need to get a blood test in order to find out your cholesterol level. The recommended levels vary depending on your risk of developing arterial disease.
High levels can increase your risk of several medical problems such as a heart attack or stroke, and the narrowing of your arteries. Any build-up within your artery walls will restrict the blood flow to your heart, brain, and the rest of your body, which in turn increases the risk of a blood clot.
There are several factors which can lead to high cholesterol. Causes of high cholesterol include:
- An unhealthy diet.
- High blood pressure.
- A family history of stroke or heart disease.
Age can also be a factor; the older you are, the greater the likelihood of your arteries narrowing.
When to Get Tested
There are several scenarios which may lead to your doctor recommending that you have your cholesterol levels tested. These include:
- Being diagnosed with coronary heart disease, a stroke, mini-stroke, or peripheral arterial disease.
- Having a family history of early cardiovascular disease.
- Being overweight.
- Having high blood pressure.
- Having diabetes.
During a test, the doctor will take a blood sample. This will then be used to determine the amount of LDL, HDL and other fatty substances such as triglycerides in your blood. To ensure that the test is accurate, you may be asked not to eat for 10-12 hours before the test.
Your blood cholesterol level is measured in units known as millimoles per litre of blood (mmoI/L). Your doctor or nurse will sit down with you and explain your results. They will also calculate whether you're at a low, moderate, or high risk of developing conditions like heart disease or a stroke within the next 10 years.
The Perfect Level
According to the NHS, the ideal total cholesterol levels should be 5mmoI/L or less for healthy adults and 4mmoI/L or less for those at high risk. For LDL, the ideal levels are 3mmoI/L or less for healthy adults and 2mmoI/L or less for those at high risk.
An ideal level of HDL is above 1mmol/L. A lower level of HDL can increase your risk of heart disease.
Your doctor won't just take your cholesterol levels into account when calculating your risks. Body mass index (BMI), age, sex, family history, ethnicity, and treatable risk factors are also important to consider.
How to Lower Your Cholesterol
The first step to lowering your levels (or preventing high levels in the first place) is to maintain a healthy, balanced diet. Consider reading the Eatwell Guide. You should also pay particular attention to the amount of saturated fat in your diet.
Eating too many foods high in saturated fat can raise the level of cholesterol in your blood. Unfortunately, it's this type of food that people in the UK are eating too much of. Foods that are high in saturated fat include:
- Cakes and biscuits.
- Sausages and fatty cuts of meat.
- Meat pies.
- Hard cheeses.
Instead, you should try and eat small amounts of foods which contain unsaturated fat, as these foods can actually reduce your cholesterol levels. Examples include oily fish such as mackerel and salmon, nuts, seeds, avocados and vegetable oils.
You should also include plenty of fibre within your diet, as this helps lower your risk of heart disease, and some high-fibre foods can help lower your cholesterol. Adults should aim for at least 30g of fibre each day. Fibre comes from a variety of foods, including:
- Wholemeal bread.
- Potatoes with skin on.
- Oats and barley.
- Fruit and vegetables.
- Nuts and seeds.
Smoking increases the risk of several cardiovascular diseases, such as a stroke and heart disease. The chemicals from a cigarette will lead to a dangerous build-up of fatty materials within the lining of your arteries.
Your blood is also more likely to clot due to smoking and your heart will also have to pump much harder due to the lack of oxygen in your blood. If you are a smoker, make a life-saving change today. Read our article on stopping smoking.
Exercising regularly will strengthen your heart and reduce your "bad cholesterol" levels. According to NHS recommendations, we should take part in at least 150 minutes of physical activity each week in order to remain fit and healthy.
Of course you don't have to go all out straight away. To begin with, the British Heart Foundation suggests breaking the 150 minutes down into ten minute sessions throughout the day. Why not start with their 10-minute workout above? You should also be realistic about your goals and make them achievable.
Everyday activities will count towards your 150 minutes, so try to keep moving throughout the day. Perhaps you could walk to the shop rather than driving? Or maybe you could cycle to work instead.
Other tips for healthy cholesterol levels include:
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Editor's Note: This article was updated on March 7th 2022 to reflect current information.