Back in post-war Finland in the 1950s, it was hard to imagine a healthier lifestyle than that of the country’s thousands of forestry workers. They spent all day outdoors in the fresh air, indulging in the kind of arduous physical labour many of us would balk at these days.
It should have been a recipe for good health and a long life. Yet, something was killing them well before their time.
It wasn’t until a landmark study in 1953 by an American researcher called Dr Ancel Keys that the mystery was solved.
Keys compared the diets of men from seven different countries to try to work out why rates of heart disease appeared to be so much higher in some than others.
He found Japanese fishermen who lived mainly on vegetables, rice and fish were easily outliving the foresters of Finland, who consumed enormous amounts of saturated fat – even routinely spreading butter on their cheese.
It was the study that finally unlocked the role of cholesterol in the rising heart disease epidemic and marked a turning point in the way medicine approached the problem.
In the decades since, high cholesterol has emerged as public enemy number one when it comes to heart disease.
GPs routinely test for it, food manufacturers market low-fat products designed to help us control it and drug firms produce billions of pills every year to treat it. But what exactly is cholesterol and why is it even in our bodies in the first place?
A vital role in keeping the body healthy
Ironically, for all its harmful effects, cholesterol does play an essential role in how our bodies work. There is naturally occurring cholesterol in every cell we have and it is particularly important in keeping the brain, nerves and skin in good condition.
For example, it forms part of the outer layer of every cell in the body. It also helps to make vitamin D – vital for strong bones and teeth – and it’s used to make bile, which helps us digest the fats we eat.
In fact, most of the cholesterol we have is produced by the body itself.
Problems emerge when additional cholesterol from our diet leads to dangerously high levels circulating in our blood. This can cause a build-up of hard deposits – called plaques – inside blood vessels.
When these deposits become unstable, they can cause a blockage which shuts off the blood supply to the heart or brain, starving them of oxygen and causing a heart attack or stroke.
The trouble is that high cholesterol causes no symptoms, so many people have no idea they are affected.
Public Health England says six out of 10 adults in England have high cholesterol.
It has carried out surveys which suggest just 46% of men aged 40-60 have had their cholesterol checked in the last year.
Around a third either couldn’t remember having a check, or definitely hadn’t had one – despite knowing it’s a risk factor for heart disease.
One easy way to find out is to request an NHS Health Check, which is available to everyone aged 40-74 and includes checks on cholesterol as well as blood pressure and diabetes risk.
Good v bad cholesterol
For years, it was thought that overall cholesterol levels were the key to working out someone’s heart disease risk, but doctors now realise the importance of distinguishing between good and bad cholesterol.
‘Good’ cholesterol is high-density lipoprotein, or HDL. It is made up of particles that travel round the bloodstream and transport ‘bad’ cholesterol – known as low-density lipoprotein, or LDL – back to the liver where it can be broken down and removed from the body safely.
LDL particles have a job to do as well. Their role is to deliver the cholesterol that’s needed to cells all round the body. But if LDL levels get too high, our arteries start to clog up. NHS guidance states our total level should be 5 or lower, our HDL reading at least one and LDL a maximum of three.
“I don’t think the public fully understands the difference between types of cholesterol and the amounts they should have to stay healthy,” says Jules Payne, chief executive officer of the charity Heart UK.
Tiny alterations can make a big difference
An estimated eight million people in the UK routinely take drugs called statins to lower their cholesterol. They are very safe, effective and have been credited with saving thousands of lives since they first emerged in the 1990s.
But some people could reduce the chances of needing to take the drugs in the first place by making a variety of small changes to their diet and lifestyle.
Barbara Kobson, senior cardiac nurse at the British Heart Foundation, says: “If people control their lifestyle and habits, they can have a positive impact on cholesterol levels.”
The key step is to reduce the amount of saturated fat in the diet. Dairy products such as butter, cheese, cream and full-fat milk are a major source of saturated fat, as is fatty meat and baked products such as pies, cakes and biscuits.
Eggs are not a problem, says Kobson, because although they do contain cholesterol, the amounts involved are too small to have a damaging effect, and they are a good source of protein and minerals.
Simply cutting down saturated fat-dense foods could potentially nudge cholesterol levels back below the danger level in some people, says Jules Payne.
“Most people are aware of the importance of cholesterol, but it’s putting lifestyle changes into practice that counts,” she says. “Everybody is busy these days so it’s important to make those changes manageable ones. We are talking about small adjustments that can easily be introduced into the daily routine.
“For example, try replacing butter with heart-healthy spreads, like Flora Proactiv or Benecol. And rather than snack on biscuits or cake, switch to a handful of nuts, such as walnuts.
“But one of the most important things you can do is to know your cholesterol numbers.”
Don’t delay – make changes today
Putting off lifestyle changes until later in life is unlikely to have any benefit, according to new research. Instead, men and women in their 30s and 40s should be thinking about switching to healthier habits to protect their hearts when they get older.
The study, by scientists at the German Research Centre for Environment Health, tracked 400,000 people – one of the biggest-ever investigations of its kind.
The results, published in The Lancet, revealed that those with the longest exposure to high cholesterol (in other words, the ones who did nothing about it early on) had the highest risk of heart attacks later on.
“This could be due to the longer exposure to harmful fats in the blood,” said lead researcher Dr Barbara Thorand.
Her team calculated that if those under 45 cut their bad cholesterol levels by leading healthier lifestyles, they’d slash the risk of heart problems by well over half.
“It means the risk reduction is much larger if cholesterol levels come down at a younger age,” she added.
The one group where lifestyle changes alone are unlikely to be enough is patients with an inherited form of high cholesterol, called familial hypercholesterolemia.
It affects an estimated one in 500 people in the UK and is often known as a silent killer as sufferers can die young.
High doses of statins are normally required to lower blood fat levels in this group.