To mark National Cholesterol Month, Dr Garry Savin, from Lumen, part of UME Health on Harley Street, shares all you need to know about cholesterol – the good the bad, the surprising truth behind heart attacks, and why a vegan diet could help.
Why do cholesterol levels matter?
High levels of cholesterol can cause some of the most serious health conditions such as premature heart disease, stroke and vascular dementia.
In fact, for 30% of people with significant heart disease the first, tragic sign is sudden death – there are no symptoms or warning flags.
Did you know:
- 2 – main coronary arteries supply the heart muscle with blood
- 100,000 – the number of times our hearts beat in an average day
- 3 million – heart beats a month – requiring a LOT of energy and oxygen, carried in our blood
- 60,000 – miles of blood vessels in our body, essential for this function
To keep these essential arteries healthy, a safe level of cholesterol is a fundamental factor.
What is cholesterol and why do we need it?
Cholesterol is a white waxy substance closely related to fat. It is found naturally throughout the body, including the blood, and a certain level is an essential requirement for life. It forms part of the cell wall of every cell in our bodies and makes other vital elements such as some hormones and bile acids to help us digest fat.
Good vs Bad
There two types of cholesterol typically measured by doctors are:
- HDL cholesterol which is the so called “healthy” or “good” form – this clears cholesterol from the arteries and transports it back to the liver
- LDL which is the so called “bad” cholesterol – this can result in fatty deposits or “plaques” on the inside walls of the arteries, leading to narrowing and blockage. This can start to build up as early as our teenage years in the Westernised world due to a diet high in saturated fats and a lifestyle relatively low in physical exercise.
What is arterial plaque?
Within plaque build-up there are also two types:
- early soft plaque which I liken to a bowl of thick custard with a thin skin on top.
- hard plaque which tends to be older and has a hard calcium topping.
It is the soft plaques which can split open and cause a sudden heart attack, whereas the hard plaques are more stable.
At Lumen, we can perform a special CT scan of the coronary arteries (if clinically indicated) which measures both the hard and soft plaque. The hard plaque is measured using a computer and is called the “calcium score” and this can classify a person’s risk of a heart event.
However, it is more important to know if there are any dangerous soft plaques or if the plaques are causing a narrowing of a coronary artery. We can measure this too as the CT scan can see inside the coronary arteries.
This scan is called a CT coronary angiogram (a CTCA) and the images can be acquired within a fraction of a second which is less than one heartbeat.
The true cause of heart attack – it’s not what you think!
Contrary to popular opinion, it is rarely a blockage of a coronary artery from cholesterol that causes a heart attack.
Instead, it is usually caused by the splitting of the surface of a soft plaque on the artery lining – this is perceived by the bloodstream as a breach in the artery wall and a thrombus (clot) made from platelets is mobilised to block the tear.
It is this thrombus that causes the sudden blocking of an artery within minutes and if this occurs in a heart artery it is called a heart attack and a similar event can occur in the brain.
How can diet and lifestyle help us reduce cholesterol?
Our cholesterol levels are determined partly by genetics and partly by lifestyle, particularly our diet. Cholesterol is thought to increase when a diet contains lots of saturated fats (animal fats).
The biggest reduction in cholesterol levels that I have seen have been in those people who switch to a vegan diet. I have frequently seen 30% drops in cholesterol levels which I have only previously seen with aggressive cholesterol lowering medications. This equates to a reduction in risk of a heart attack by around 60% so is very significant. So, not only can a vegan diet help save the planet it can also help us preserve the health of our arteries.
Good foods to help reduce the absorption of cholesterol in our diet are rolled oats. Also plant sterols and stanol products can help though benefits are marginal. Reducing foods high in saturated fats is best.
Exercise can improve cholesterol levels as can reducing alcohol and quitting tobacco smoking. Some studies have shown that high stress levels can cause elevated cholesterol levels.
Some medical causes of high cholesterol include an underactive thyroid, kidney disease and some medications such as antidepressants.
Most people can change their levels but in some it is high because of genetics and if it is too high then those people need to take a medicine as they are more at risk of premature arterial corrosion.
What cholesterol level should we aim for?
We have moved away from exact numbers as cholesterol level is just one part of a jigsaw puzzle of risk factors. Having said that it is almost impossible to get arterial disease if cholesterol is below 3.8 – that is millimoles per Litre (mmol/L).
How do I know if I have high cholesterol?
There are no early symptoms, so the only way to know your cholesterol level is to request that a healthcare professional measure it on a blood sample.
And the results can be quite unpredictable – the lowest natural cholesterol I ever measured was in an obese, sedentary lorry driver who ate a very fatty diet and had a total cholesterol level of just 2.5mmol/L.
I have also seen patients who suffered their first heart attack at age 35 because of very high cholesterol levels, who only knew about it when it was measured in their coronary care hospital bed.
What are the signs of a high cholesterol?
Sometimes high levels can cause physical signs on the body such as white rings around the iris in the eyes or lumps in the tendons which all doctors are trained to detect but these are notoriously unreliable, and it is good to have your blood levels properly measured.
At Lumen we have latest technologies- to measure detailed cholesterol blood profiles in all of our advanced health assessments, from a stress echo test to look for signs of narrowed coronary arteries to a CTCA scan to precisely image the inside of the heart arteries in high resolution.
This CT technology has been a game changer as we have been able to detect very significant coronary artery disease and high-risk plaques in many patients who otherwise wouldn’t know that they had a problem to address.
Top health tip:
Cholesterol levels have a significant impact on health and can be the difference between an early heart attack or not. What better time than National Cholesterol Month to check your own levels?
In my view we should all know our wedding anniversary, spouse’s birthday, cholesterol levels and blood pressure to stay in optimum health!