Understanding the causes of high cholesterol

What is cholesterol, and how can I adopt a low cholesterol diet?

Making informed and healthy dietary choices can sometimes feel more confusing than it should. Dietary advice can seem ever-changing and leave you feeling overwhelmed and confused about what you should, or shouldn’t, be eating.

However, there are a few things that remain a constant, and a little bit of knowledge can go a long way in helping you keep your body healthy. One of these is cholesterol. Read on to learn what exactly cholesterol is, some of the causes of high cholesterol, and changes you can make to your lifestyle and diet to stay healthy.

What is cholesterol?

Cholesterol is a fat-like substance made by the liver. It is essential in the production of oestrogen, testosterone, and vitamin D (which helps to keep bones, teeth, and muscles healthy). Cholesterol is also present in every cell in our bodies, aiding with digestion and helping to protect us from cardiovascular disease.

As well as being produced naturally in our bodies, cholesterol can also be found in certain food types, such as meat, poultry, eggs, fish, and dairy products.

Coconut oil may have a healthy image, but usually contains more saturated fat than butter

Cholesterol is carried in our bloodstream by protein molecules called lipoproteins. There are two main types of lipoproteins, and we need to keep a good balance of each to stay healthy. Generally, one type is helpful to us, and the other is not. These two types are commonly known as ‘good’ and ‘bad’ cholesterol.

What is ‘bad’ cholesterol and how can your diet affect it?

According to The World Heart Federation, cholesterol is responsible for 4.4 million deaths every year.

Low-density lipoproteins (LDL), known as ‘bad’ cholesterol, can build up on artery walls and, over time, form a plaque. This can lead to a hardening of arteries and reduced blood flow, which can in turn affect cells and organs and lead to blood clots, heart disease, heart attacks, and strokes. According to The World Heart Federation, cholesterol is responsible for 4.4 million deaths every year.¹

When people talk about the causes of high cholesterol, what they’re really talking about is LDL. Lack of exercise, higher weight, smoking, and alcohol consumption can all contribute to a rise in LDL. Too much saturated fat in your diet can also cause LDL to rise. Saturated fats can be found in meats, fried food, pasties, pies, and dairy products, as well as in vegetable oils made from coconut, palm, and cocoa. (Coconut oil may have a healthy image, but usually contains more saturated fat than butter!) Unfortunately, with dairy being so high in saturated fat, this means the same is usually true of cakes, puddings, chocolate, and biscuits.

The good news is that the opposite is also true: weight loss, exercise, quitting smoking, and drinking less are shown to be positive steps towards lowering total cholesterol while raising levels of ‘good’ cholesterol. Also, while it’s important to limit our intake of saturated fat, a little in moderation can be fine as part of a healthy diet.

In general, adopting a low fat, high-protein, high-fibre diet is the best route to help lower ‘bad’ cholesterol, raise ‘good’ cholesterol, and improve your heart health.

Sometimes though, things aren’t fair. Your personal and family medical history may mean you have an increased risk of cardiovascular disease (CVD). Familial Hypercholesterolaemia is an inherited genetic condition that can cause high cholesterol, even in people with a healthy lifestyle. In this case, your doctor may prescribe statins, a group of medicines that can help lower your level of LDL. Statins may also be recommended if you have been diagnosed with a form of CVD.

What other factors can impact cholesterol levels?

Normal cholesterol levels vary by age and tend to rise as we get older. A person’s sex can make a difference too, with people assigned male at birth often having higher levels of LDL.

After menopause, the LDL levels of people assigned female at birth may increase,² but research has found that the oestrogen in hormone replacement therapy (HRT) can reduce cholesterol levels.³

What is ‘good’ cholesterol and how can your diet affect it?

High-density lipoproteins (HDL), known as ‘good’ cholesterol, carry LDL back to the liver to be broken down. These are antioxidant and anti-inflammatory and protect our artery walls against the damage caused by LDL, even helping to remove arterial plaque build-up.

In general, adopting a low fat, high-protein, high-fibre diet is the best route to help lower ‘bad’ cholesterol, raise ‘good’ cholesterol, and improve your heart health. Bear in mind though, that nuts and fruits are high in calories, so, as is usually the case, moderation is key when it comes to diet.

Another way to help lower cholesterol is to consider switching to healthier, lower-fat cooking methods. Instead of frying, try steaming, poaching, or baking. Instead of butter, try avocado, olive oil, or plant-based fat spreads.

If you have children, try to get them involved in healthy meal planning, shopping, and cooking. Also, so-called ‘treats’, such as calorific fast food and sugar-filled fizzy pop, increase the risk of weight gain, raised levels of LDL cholesterol and heart disease, so should remain only an occasional indulgence.

Check nutrition labels in the store

When trying to assess the nutritional value of different foods in the store, labels often show so much information that it can be difficult to understand all the numbers and percentages and how they relate to each other.

Similar products may contain very different amounts of fat, so it’s always worth comparing options.

Various schemes have been introduced around the world, aimed at simplifying this information. Depending on where you are in the EU, you may recognise ‘The Reference Intake Figures’, ‘The Nordic Keyhole Symbol’, or ‘The Nutri-Score Labelling Scheme’. The UK has ‘Traffic light labelling’, while further afield, Singapore has ‘The Healthier Choice Symbol’ and The Czech Republic uses ‘The Choices Logo’.

Some of these schemes use a similar colour-coding system to display nutritional information on the front of the packet, and the general recommendation is to choose foods with more greens and yellows, while being more mindful of reds.

It is important that we don’t avoid fat altogether as we do need some to keep a balanced diet. However, when it comes to cholesterol, particularly try to avoid reds for saturated fat. It’s also worth remembering that similar products may contain very different amounts of fat, so it’s always worth comparing options.

While it is very common, this colour-coded ‘front of pack’ labelling is still voluntary, so if this isn’t available, check the ‘back of pack’ labelling, which is mandatory. This labelling will provide more detailed information, usually shown in ‘per 100g’, or ‘per-portion’, so that you can easily compare products. However, it’s worth remembering that a manufacturer’s definition of a portion or serving size may be different from yours.

There are also some useful barcode-scanning apps available which can help you understand the numbers and track your nutritional intake.

Does high cholesterol present with symptoms?

High cholesterol does not usually present with symptoms. The only way to diagnose high cholesterol is through a blood test called a lipid panel or lipid profile, carried out by your doctor.

The British Heart Foundation recommends having your cholesterol checked every five years if your cholesterol levels are borderline or normal.⁴ However, risk factors such as personal or family history, age, and obesity may mean you’ll need to have it checked more often.

Remember everyone is different, so it’s always important to speak with your doctor or dietitian about what’s best for you.