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All you need to know about cholesterol

This blog covers everything - from what 'high cholesterol' really means, to the things you can do to keep your cholesterol levels in check. 

What is cholesterol? 

Cholesterol is a fatty substance (a lipid) found in every cell in the body and is produced naturally by the liver. It is essential for the maintenance of cell membranes, production of vitamin D and bile acid, along with the production of vital hormones, such as testosterone and oestrogen. 

Cholesterol travels around the body bound within small proteins called lipoproteins. Lipoproteins are particles made from fat and protein. They carry cholesterol and triglycerides (another type of lipid) through your bloodstream. The two main forms of lipoprotein are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).  

High-density lipoproteins (HDL) remove cholesterol from our tissues and take it back to the liver where the cholesterol can be recycled and excreted. HDL is often referred to as the “good cholesterol” and offers a protective role. 

In contrast, low-density lipoproteins (LDL) are commonly known as “bad cholesterol” because they carry cholesterol from the liver to our tissues and may deposit it on our artery walls. Although high levels of LDL in our bodies are proposed to have a negative effect, these lipoproteins are still crucial for our health as they deliver essential cholesterol molecules to our cells when needed.

Triglycerides are another type of lipid, which is different from cholesterol. Triglycerides are a source of energy and energy storage for the body. When you consume more calories than your body can use right away, your body stores triglycerides in your fat cells. Triglycerides are transported in the blood by lipoproteins called chylomicrons and VLDLs (very low-density lipoproteins). If your blood triglyceride levels are high, it can mean you are at greater risk of heart disease, liver disease and diabetes.

What is high cholesterol? 

Cholesterol serves many essential functions in the body. However, it is “bad cholesterol” (LDL and VLDL) which it is good to keep track of. If you have too much bad cholesterol in your blood, this may be damaging for health. Over time the bad cholesterol may build up in our artery walls leading to the development of ‘fatty plaques’. Plaques can narrow our arteries and raise the risk of a blood clot. If a blood clot blocks an artery, it stops the blood supply (and therefore the oxygen and essential fuel) which can reach your heart or brain, often leading to a heart attack or stroke. 

According to Heart UK, over half of UK adults are currently living with raised cholesterol [1].

What are the symptoms of high cholesterol? 

There are no obvious symptoms of high cholesterol and is why it is often referred to as “the silent killer”. Most people do not realise they are living with high levels of bad cholesterol until they develop serious health problems. Because of this, it is beneficial to regularly monitor your cholesterol levels to make sure you are not at risk.

What causes high cholesterol? 

Several factors can increase your risk of high cholesterol, including:

  • Smoking – smoking makes your LDL cholesterol ‘stickier’ – so it clings to your artery walls and also lowers your level of HDL cholesterol [2].
  • Diet – medical professionals currently believe that eating too much saturated fat (found mainly in animal foods) can raise your cholesterol. 
  • Obesity – having a body mass index (BMI) of 30 or greater puts you at higher risk of having high cholesterol. 
  • Lack of exercise – exercise helps boost the amount of your body’s HDL, or ‘good’, cholesterol [3].
  • Age – as you age, your liver becomes less able to remove cholesterol from the blood, increasing the likelihood of having high cholesterol [4]
  • Menopause - women may find that their cholesterol levels rise during menopause. Research has found that menopause is associated with a more “atherogenic” (potentially damaging) lipid profile [5]. It may be beneficial that women monitor cholesterol levels as they enter the menopausal transition to assess their risk of heart attack and stroke. 
  • Genetics – a genetic predisposition to high cholesterol levels and a family history may increase your risk.
  • Thyroid disease - hormones produced by our thyroid gland play a major role in the regulation of metabolism and aid the breakdown of fats, including cholesterol. If your thyroid gland is under- or overactive, the body's ability to process cholesterol can be affected, and this may lead to hypercholesterolemia (high cholesterol levels).
  • Diabetes - people with uncontrolled diabetes, who have persistently high sugar levels in their bloodstream are more likely to have unhealthy cholesterol an triglyceride levels.

How to get your cholesterol levels checked 

Heart UK recommends that all UK adults should get a cholesterol check – no matter how old you are or how healthy you feel [1].

There are no obvious tell-tale signs of high cholesterol in the body, so the only way to be confident of your cholesterol levels is to get a check. 

A cholesterol check involves a simple blood test. You can ask your GP for a cholesterol test if you have not had a test before and you're over 40, overweight, or high cholesterol or heart problems run in your family. 

Medichecks’ Cholesterol Blood Test is another way to measure your triglyceride and cholesterol levels as well as determining your risk of heart disease based on the ratio of HDL to total cholesterol. This test is a simple finger prick test which can be done in the comfort of your own home. You can view your doctor reviewed results in your personal dashboard along with recommendations on the next steps to take. 

What do the results of a cholesterol test mean? 

A cholesterol test will include different types of cholesterol. Let’s take a look at what each type means: 

  • Total cholesterol (TC) - total cholesterol is a measure of all the cholesterol in your blood, both good (HDL) and bad (LDL, VLDL and non-HDL).
  • Non-HDL cholesterol - non-HDL cholesterol includes all the cholesterol molecules which are not HDL (or 'good' cholesterol). It, therefore, includes all the non-protective and potentially harmful cholesterol in your blood. As such, it is considered to be a better marker for cardiovascular risk than total cholesterol and LDL cholesterol.
  • HDL cholesterol - HDL cholesterol (high-density lipoprotein, or 'good' cholesterol) helps clear the cholesterol out of your arteries. In contrast, your LDL cholesterol (low-density lipoprotein, or 'bad' cholesterol) may damage them.
  • TC: HDL ratio - The TC: HDL ratio is calculated by dividing your total cholesterol value by your HDL cholesterol level. It is used as a measure of cardiovascular risk because it gives a good insight into the proportion of your total cholesterol which is "good".  

What is a normal cholesterol level? 

The table below shows the ideal cholesterol and triglyceride levels for healthy adults in the UK [1]:

Type of cholesterol  (mm/L)
Total (serum) cholesterol below 5.0
Non-HDL cholesterol below 4.0
LDL cholesterol below 3.0
HDL cholesterol

male: above 1.0

female: above 1.2

TC:HDL ratio

Above 6 is high-risk

The lower this figure the better

If you have high cholesterol or an unhealthy balance of blood fats, our expert doctors will provide you with a personalised, healthy lifestyle and diet changes to bring these levels down to a healthy level. 

Do cholesterol levels differ for men and women?

Woman naturally have higher HDL cholesterol levels than men due to hormonal differences [6]. Women should aim for an HDL cholesterol level above 1.2mmol/L while men should aim for above 1mmol/L.

Pregnancy and cholesterol levels

During pregnancy, cholesterol and triglyceride levels increase naturally. As the pregnancy develops, there is increased availability of nutrients for the placenta to support the growth and development of the baby [7].

This temporary increase is normal and poses no harm to the baby or mum. We recommend having your cholesterol levels checked three months after you have given birth. 

How do I lower my cholesterol levels? 

In some case, your doctor may prescribe medications, such as statins, to help lower your cholesterol levels. However, encouragingly, there are several lifestyle changes which you can make, which can successfully reduce your cholesterol levels and decrease the risk of fatty plaques building up in the arteries.

1.    Improve your diet by eating heart-healthy foods

Making a few changes to your diet choices can significantly reduce your cholesterol levels, increase the amount of good HDL cholesterol in your body and improve your heart health:

  •  Increase your intake of fibre

Soluble fibre reduces the amount of cholesterol which can be recycled by the body and therefore plays a crucial role in lowering total and LDL-cholesterol levels naturally [8]. Good sources of soluble fibre include oats and oat bran, fruits, beans, lentils, and root vegetables. Insoluble fibre (found in foods such as carrots, wheat bran and beans) also has heart-healthy benefits, including making you feel fuller for longer and reducing your overall calorie intake.

  • Follow a Mediterranean diet

The healthy living habits of those in countries which border the Mediterranean Sea, such as France, Greece, Italy and Spain, have been linked with lower LDL cholesterol levels [9] and a lower risk of cardiovascular diseases [10]. A traditional Mediterranean diet is usually low in meat and dairy products, high in vegetables, fruits, legumes, nuts, grains, fish, and unsaturated fats such as olive oil. 

Find out everything you need to know about the Mediterranean diet here.

  • Reduce saturated fats

Saturated fat, found in red meat, dairy products and some plant oils such as coconut oil and palm oil, may raise total cholesterol levels [11-13]. For healthier options, choose leaner cuts of meat, low-fat dairy and plant-based fats (such as olive and rapeseed oil). In general, most plants do not contain saturated fats, so eating more fresh fruit and vegetables as well as seeds, nuts, and whole grains can help to lower cholesterol levels. 

  •  Eat more foods rich in omega-3 fatty acids

Omega-3 fatty acids are essential for the body but are only obtained through our diet. Researchers have found that omega-3 fatty acids may be beneficial for heart health [14]. Increasing your intake of oily fish linseed, and chia seed, and supplementing cod liver oil are all effective ways to increase omega-3 levels. 

2.    Exercise regularly

Having an active lifestyle is an excellent way to help lower your cholesterol levels. The NHS recommends 150 minutes of moderate exercise a week (such as brisk walking or dancing). Exercise may increase your level of good HDL cholesterol [3] meaning that more cholesterol can be transported from the body tissues back to the liver where it is expelled. Exercise is also essential for maintaining a healthy weight. Being overweight or obese is a risk factor for having high cholesterol levels and puts you at an increased risk of developing conditions such as diabetes and heart disease. 

3.    Cut the alcohol and cigarettes

Smoking is bad for your health - everyone knows that, so it is no surprise that smoking can raise cholesterol levels. Smoking lowers levels of HDL cholesterol [2] and can injure the lining of the blood vessels. Quitting smoking can help to reduce cholesterol levels and decrease blood pressure, therefore improving your heart health. Excessive alcohol consumption for a prolonged period can increase blood triglyceride and cholesterol levels, reduce how effectively cholesterol can be cleared from the blood and may lead to the development of heart disease [15]. It is advised that both men and women should not drink more than 14 units of alcohol a week, along with regularly having alcohol-free days, to minimise the health risks that alcohol can cause.


References

1.    Heart UK. 2020  [cited 2020 22nd October]; Available from: https://www.heartuk.org.uk/.
2.    Heart UK. Quit smoking.  [cited 2020 22nd October]; Available from: https://www.heartuk.org.uk/healthy-living/quit-smoking.
3.    Steven Mann, Christopher Beedie, and Alfonso Jimenez, Differential effects of aerobic exercise, resistance training and combined exercise modalities on cholesterol and the lipid profile: review, synthesis and recommendations. Sports Medicine, 2014. 44(2): p. 211-221.
4.    AE Morgan, et al., Cholesterol metabolism: a review of how ageing disrupts the biological mechanisms responsible for its regulation. Ageing research reviews, 2016. 27: p. 108-124.
5.    Panagiotis Anagnostis, et al., Effects of menopause, gender and age on lipids and high-density lipoprotein cholesterol subfractions. Maturitas, 2015. 81(1): p. 62-68.
6.    Jacques E Rossouw, Hormones, genetic factors, and gender differences in cardiovascular disease. Cardiovascular Research, 2002. 53(3): p. 550-557.
7.    Heart UK. Pregnancy and Blood Fats.  [cited 2020 22nd October]; Available from: https://www.heartuk.org.uk/cholesterol/pregnancy-and-blood-fats.
8.    Ghada A Soliman, Dietary fiber, atherosclerosis, and cardiovascular disease. Nutrients, 2019. 11(5): p. 1155.
9.    Caroline Richard, et al., Effect of the Mediterranean diet with and without weight loss on surrogate markers of cholesterol homeostasis in men with the metabolic syndrome. British journal of nutrition, 2012. 107(5): p. 705-711.
10.    Nerea Becerra-Tomás, et al., Mediterranean diet, cardiovascular disease and mortality in diabetes: A systematic review and meta-analysis of prospective cohort studies and randomized clinical trials. Critical reviews in food science and nutrition, 2020. 60(7): p. 1207-1227.
11.    Heart UK. What is cholesterol.  [cited 2020 22nd October]; Available from: https://www.heartuk.org.uk/cholesterol/what-is-cholesterol.
12.    British Dietetic Association (BDA). Fat.  [cited 2020 22nd October]; Available from: https://www.bda.uk.com/resource/fat.html.
13.    Nithya Neelakantan, Jowy Yi Hoong Seah, and Rob M van Dam, The Effect of Coconut Oil Consumption on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Clinical Trials. Circulation, 2020. 141(10): p. 803-814.
14.    Heart UK. Omega 3 fats.  [cited 2020 22nd October]; Available from: https://www.heartuk.org.uk/low-cholesterol-foods/omega-3-fats.
15.    Heart UK. Alcohol.  [cited 2020 October 22nd]; Available from: https://www.heartuk.org.uk/low-cholesterol-foods/alcohol.