Most of us carry a mental image of the person most likely to suffer a heart attack: Overweight, perhaps middle-aged, living on fried food and rarely exercising.

But according to leading cardiologist Dr Oliver Guttman, that stereotype can be dangerously misleading.

One of the biggest risk factors for cardiovascular disease is high cholesterol – and it can affect people who appear slim, fit and otherwise healthy, he warns.

While unhealthy habits such as eating a diet high in saturated fats, drinking heavily and avoiding exercise can increase the risk of heart attack, Dr Guttman stresses that body shape alone does not tell the full story.

‘Cholesterol is influenced by many factors beyond body weight,’ he says. ‘Genetics, diet, age and physical activity can all have an effect on cholesterol levels.

‘The problem is that high cholesterol usually causes no symptoms – until it is too late.’

Often described as a ‘silent killer’, high cholesterol increases the risk of heart attack, stroke and other forms of cardiovascular disease – the leading cause of death and disability in the UK, responsible for around 170,000 deaths every year.

We asked Dr Guttman to sort fact from fiction – and the good cholesterol from the bad – to help people better understand how to protect themselves from heart disease.

What is cholesterol – and is it all bad? 

First, it is important to understand what cholesterol actually is. Cholesterol is a fat-like substance, known as a lipid, that is found in every cell in the body.

Not all cholesterol is harmful.

HDL cholesterol, often referred to as the ‘good’ type, helps carry excess cholesterol in the bloodstream back to the liver where it can be broken down and removed from the body.

But LDL cholesterol, the so-called ‘bad’ type, behaves differently. It can build up in the walls of arteries, forming fatty deposits that narrow blood vessels and increase the risk of heart attack and stroke.

If HDL levels are too low, this harmful cholesterol can accumulate more easily.

Dr Guttman says this is why the total cholesterol figure alone does not tell the whole story.

‘Two people can have the same total cholesterol level but very different cardiovascular risk depending on how those components are balanced,’ he explains.

‘Doctors also consider other factors such as blood pressure, age, smoking status, diabetes and family history when assessing heart disease risk – so it’s never about focusing on a single number alone.’

I’m slim and healthy, can I still have high cholesterol? 

Many people assume that if they are slim and physically active they do not need to worry about their cholesterol.

But according to Dr Guttman, that belief can be dangerously misleading.

‘Being slim does not guarantee healthy cholesterol levels,’ he says. ‘Cholesterol is influenced by many factors beyond weight.

‘Some people who appear very fit and maintain a healthy weight can still have high cholesterol because their body naturally produces more of it.’

High cholesterol can also run in families.

And it is not just overall body fat that matters, but visceral fat – the fat stored deep inside the abdomen around the organs.

This type of fat is linked to higher levels of harmful LDL cholesterol and greater cardiovascular risk.

Research shows that diets high in saturated fat and ultra-processed foods can promote visceral fat storage, even in people who appear slim.

‘The only way to know your levels is through a blood test,’ Dr Guttman says. ‘You should have them checked regularly to make sure they are not creeping up unnoticed.’

As a woman do I need to be as worried about cholesterol? 

While women are generally less likely than men to suffer a heart attack earlier in life, cholesterol is still an important risk factor.

Dr Guttman explains that women tend to develop heart disease later partly because of the protective effects of oestrogen before menopause.

But the risk rises sharply after menopause.

‘Heart disease remains one of the leading causes of death in women,’ he says.

Another challenge is that symptoms in women are often less typical than the classic crushing chest pain commonly described by men.

‘For these reasons it’s important that women also pay attention to their cardiovascular health – including cholesterol levels and other risk factors – and seek medical advice if they develop concerning symptoms.’

Will statins cause horrible side effects? 

Statins are among the most widely prescribed medicines in the world and are highly effective at lowering cholesterol and reducing the risk of heart attack and stroke.

Despite this, many patients are reluctant to take them. Statins are often blamed for aches and pains that commonly develop in midlife – even though large clinical trials suggest true statin side effects are far less common than many people believe.

One of the biggest challenges doctors face is that many patients simply do not take the medication regularly. Studies show a significant proportion stop within the first couple of years, which is one reason many people fail to reach healthy cholesterol targets.

For those who genuinely cannot tolerate a particular statin, doctors can often try a different type or adjust the dose. In some cases, patients may be referred to a specialist clinic to consider alternative cholesterol-lowering treatments.

Like all medicines, statins do carry some risks – but serious complications are very rare.

A severe muscle condition called rhabdomyolysis, in which muscle tissue breaks down and can damage the kidneys, occurs in only a tiny fraction of patients. There is also evidence statins can slightly increase the risk of developing type 2 diabetes, and they can occasionally affect liver function, which is why doctors monitor patients with blood tests.

However, experts say these risks are small compared with the benefits for people with raised cholesterol or increased cardiovascular risk.

Dr Guttman says: ‘For people with raised cholesterol or cardiovascular risk, the benefits of statins in preventing heart attacks and strokes generally far outweigh the risks and doctors consider these factors carefully before recommending treatment.’

Can diet reverse high cholesterol?

While statins are powerful medications, Dr Guttman says they do not replace the need for a healthy lifestyle.

Diet can still play an important role in lowering cholesterol levels.

Eating foods rich in soluble fibre, such as oats, beans and lentils, can help reduce levels of harmful LDL cholesterol.

Oats contain beta-glucan, a type of soluble fibre that forms a gel-like substance in the gut and binds to cholesterol, preventing some of it from being absorbed into the bloodstream.

Research published earlier this year found that eating porridge for just two days could cut LDL cholesterol levels by up to 10 per cent, particularly in people with metabolic syndrome – a cluster of conditions including obesity, high blood pressure and raised blood sugar that increase the risk of heart disease.