What is cholesterol and how can we lower it?

Young people may have to start being more mindful about their cholesterol levels after a new study found that exposure to high or fluctuating cholesterol early in life might heighten the risk of atherosclerosis.

Atherosclerosis is the narrowing of the arteries due to a build-up of fatty deposits and can lead to heart disease and strokes.

The study – led by scientists from the University of Cambridge and published in Nature – involved feeding two groups of mice a cholesterol-rich diet, either intermittently or continuously.

Ziad Mallat, a British Heart Foundation (BHF) professor of cardiovascular medicine at the University of Cambridge, said: “We found that an intermittent high-fat diet starting while the mice were still young – one week on, a few weeks off, another week on, and so on – was the worst option in terms of atherosclerosis risk.”

In addition, other researchers analysed data of 2,000 people from the Cardiovascular Risk in Young Finns Study and found that those who had been exposed to high cholesterol levels as children were more likely to have the biggest build-up of plaque in the arteries.

But what is cholesterol exactly, and what lifestyle changes can we make to lower it?

What is cholesterol?

“Cholesterol is a fatty substance found in your blood that is essential for building cells and producing certain hormones,” explains Dr Oliver Guttmann, a consultant cardiologist at The Wellington Hospital part of HCA Healthcare UK.

The two main types of cholesterol are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

“LDL is often called ‘bad’ cholesterol because high levels can lead to plaque build-up in arteries, increasing the risk of heart disease,” explains Guttmann. “HDL, on the other hand, is known as ‘good’ cholesterol because it helps remove LDL from the bloodstream.”

Cholesterol levels in the UK are measured in millimoles per litre (mmol/L).

“For most people, a total cholesterol level of 5 or below is considered healthy,” says Dr Chun Tang, GP and medical director at Pall Mall Medical. “LDL cholesterol should ideally be less than 4, while HDL should be 1 or above.

“Levels above these ranges might be too high and could put you at risk for health issues, so it’s good to keep an eye on them and get further medical tests if you suspect your levels may be too high,” adds Tang.

What are the dangers of high cholesterol?

“High cholesterol, especially too much LDL, can lead to fatty deposits in your arteries,” explains Tang. “Over time, this build-up can narrow your arteries, making it harder for blood to flow.

“This increases your risk of heart disease, stroke, and other serious health problems,” adds Tang. “It’s like a traffic jam in your bloodstream, things just can’t move along as they should be doing.”

Certain demographics are more prone to high cholesterol.

“Older adults often experience higher cholesterol levels due to ageing and changes in metabolism,” says Guttmann. “Genetic factors also play a significant role; conditions like familial hypercholesterolemia cause high cholesterol from a young age.

“Additionally, people with obesity, poor dietary habits, and sedentary lifestyles are more likely to develop high cholesterol.”

Why is it important to me mindful of it earlier in life?

“Being mindful of cholesterol levels from an early age is crucial because it allows for early intervention and lifestyle adjustments that can prevent long-term health issues,” highlights Guttmann.

Tang agrees and adds: “High cholesterol doesn’t usually have symptoms, so it’s easy to ignore. By being proactive, you can avoid complications like heart disease or stroke later in life.”

So, how can we lower it?

Look at your diet

“Focus on eating more fruits, vegetables, whole grains, and lean proteins,” advises Guttmann. “Reduce intake of saturated and trans fats, found in fatty meats, fried foods, and processed snacks. Opt for healthy fats like those in avocados, nuts, and olive oil.”

Exercise regularly

“Aim for at least 150 minutes of moderate aerobic activity, such as brisk walking or cycling, each week,” recommends Guttmann. “Regular exercise helps raise HDL cholesterol and lowers LDL cholesterol and triglycerides.”

Quit smoking

“Smoking lowers HDL cholesterol and damages blood vessels, so quitting can improve your cholesterol levels and overall heart health,” explains Guttmann.