For years, the story of heart health has been framed as a battle between good and bad.
In one corner: HDL (high-density lipoprotein), the heroic ‘good’ cholesterol that helps clear your arteries and keep things flowing. In the other: LDL (low-density lipoprotein), the so-called ‘bad’ cholesterol that builds up in your blood vessels and quietly raises your risk of heart disease.
It’s a neat, simple narrative. And for decades, it’s produced one clear instruction from doctors the world over: keep your LDL low, and you’re on the right track.
There’s just one problem. It turns out the story has a third character: a little-known, rarely tested type of cholesterol that can account for around a third of your total levels – and one that even statins, the most widely prescribed cholesterol-lowering drug in the world, are significantly less effective at tackling.
It’s called remnant cholesterol. And experts now think it could be the most dangerous type of the three.
“I previously called them the good, the bad and the ugly,” says Børge Nordestgaard, a clinical professor at the University of Copenhagen and one of the world’s leading experts on cholesterol. “LDL is the bad guy, but remnant cholesterol is even worse.
“It has more or less been ignored by many clinicians… and that’s not a good idea.”
The third player
To truly understand remnant cholesterol, it helps to start by ditching a common myth. Despite what you’ve been told, cholesterol itself isn’t inherently good or bad. It’s simply a fatty substance your body uses to build cells, produce hormones and keep your nervous system ticking. Sure, cholesterol can contribute to clogged arteries when it builds up in the wrong place – but you wouldn’t be alive without it right now.
Those ‘good’ and ‘bad’ labels? Well, they’re not really about the cholesterol at all. They’re more about the particles that carry it.
You see, just like oil in water, cholesterol can’t dissolve in your blood, so your body has to package it up and transport it.
It can help to think of cholesterol as a parcel that needs a special delivery van to reach its destination. Some of those van particles drop cholesterol off at your tissues and, occasionally, your arteries (LDL). Others pick it up and carry it back to the liver to be recycled (HDL).
It’s such behaviours that lead to particles being called ‘good’ or ‘bad’.
So, what are the ‘ugly’ cholesterol particles? Well, they’re another class of vehicle entirely. Known as chylomicrons and VLDLs (very low-density lipoproteins), these particles can be huge – up to 50 times wider than LDLs.
For this reason, you can think of them as the mega-lorries in your bloodstream, hauling vast loads of cargo around your body.
Unlike the LDL and HDL particles, these lorry particles don’t actually carry cholesterol as their main payload. Instead, most of their haul is taken up by triglycerides – an energy-dense fat your body uses as fuel. Cholesterol makes up just 1–3 per cent of the total load, serving merely a structural role in stabilising the triglycerides.
At first, 3 per cent sounds like a teeny tiny proportion. Something barely worth worrying about. Just a few small smidges of cholesterol within a huge, triglyceride-packed lorry.
Yet because these lorry particles are so large, that tiny percentage adds up – the actual amount of cholesterol they carry is enormous – up to 40 times more than LDLs (the ‘bad’ cholesterol), according to some estimates.
Fortunately, while the lorry is fully loaded with triglycerides, the cholesterol within is largely harmless – the particles are simply too unwieldy to burrow into your artery walls.
However, the triglycerides don’t stay for long. As the lorry particle moves through your bloodstream, it sheds triglycerides at each stop, delivering energy to your muscles and tissues, effectively growing lighter with every delivery.
Eventually, what remains is a cholesterol-rich husk – and it’s this stripped-down particle that’s known as remnant cholesterol.
In a healthy person, they aren’t really an issue – the liver recognises these remnant particles and mops them up. But if your body produces too many – through diet, weight gain or genetics – the liver simply can’t keep up. The remnants linger in the bloodstream far longer than they should. And gradually, some find their way into your artery walls.
That’s when things start to unravel.
As you might expect, a particle lodged in your arteries carrying up to 40 times more cholesterol than LDL is a serious problem.
Unlike a splinter you can remove, remnant cholesterol stays firmly lodged, triggering an immune response. Soon, white blood cells rush to the scene and try to gobble up the cholesterol, but they can’t digest it. So they die there, gradually forming the fatty plaques that narrow and harden your arteries over time. And if a plaque grows large enough – or suddenly ruptures – it can block blood flow, triggering a stroke or heart attack.
Danger zone
If all this sounds bad, that’s because it is. Research has found that people with higher levels of remnant cholesterol and triglycerides are twice as likely to die from cardiovascular disease as those with lower levels.
Despite this, most of the concern around cholesterol still centres on ‘bad’ LDL. Some of this is justified. After all, as Nordestgaard points out, high LDL levels are the more common problem among the general population – around one in two people have elevated levels, compared with roughly one in three for remnant cholesterol. But that focus could allow something important to slip through the net.
And the evidence suggests it does. For instance, in one study, nearly 12 per cent of patients with cardiovascular disease still had high remnant cholesterol despite hitting their LDL targets. In other words: their standard blood test gave them the all-clear – but they were still at risk.
In another study of 113,000 people, those with low LDL but high remnant cholesterol still had a 15 per cent higher risk of stroke.
Part of the problem is that remnant cholesterol isn’t routinely measured. A comprehensive blood test shows your LDL, HDL, triglycerides and total cholesterol levels – but remnant cholesterol rarely gets its own line. And unlike LDL, there’s no officially agreed threshold for what counts as dangerously high anyway.
If your test results include figures for LDL and HDL, you can calculate your remnant cholesterol by taking your total cholesterol figure and subtracting both your LDL and HDL readings.
If not, the best proxy, says Nordestgaard, is your triglyceride reading. Because triglyceride and remnant cholesterol levels are closely linked, a high triglyceride figure is a reliable signal that remnant cholesterol is elevated too. “If this value is high, it will tell you that remnant cholesterol is high,” he says.
The benchmarks for high triglyceride levels are:
- Up to 150 mg/dL is healthy
- 150–199 mg/dL is mildly elevated
- 200–499 mg/dL is moderately high
- Above 500 mg/dL is very high
Fight back
So let’s say your triglycerides are high and you suspect your remnant cholesterol is too. What can you do about it? The bad news is that statins, the most widely used weapon against cholesterol, aren’t particularly well-equipped to fight it.
Statins have been prescribed to reduce LDL in high-risk individuals for around 40 years – and they’re remarkably effective at that job. But remnant cholesterol is a different beast. “If statins reduce LDL by 20 per cent, they reduce remnants by about 10 per cent,” says Nordestgaard. Half the effect, in other words, for a particle that may be twice as dangerous.
The good news is that a new generation of drugs is catching up. In the past year alone, around six new treatments have shown the ability to cut remnant cholesterol by 50–80 per cent. “There’s a really good pipeline of drugs that can very efficiently reduce remnant cholesterol,” says Nordestgaard.
The bad news: those drugs aren’t widely available yet – and even when they are, they’ll likely work best alongside lifestyle changes.
While both LDL and remnant cholesterol have a genetic component, remnant cholesterol is particularly sensitive to what you eat, how much you move, and how much you weigh. And unlike some health risks, these are levers most of us can pull.
Of course, if you’re concerned about remnant cholesterol, your first port of call should be your doctor. They can arrange a lipid profile blood test, talk through your results, and discuss whether medication might be appropriate.
But medication and lifestyle work best together – and the right changes can both bring existing levels down and stop them from building up in the first place.
Here are the most impactful things you can do…
1. Diet changes
Like other types of cholesterol, what you eat plays a big role in keeping remnant levels in check. And that means cutting back on foods high in sugar and refined carbohydrates – fizzy drinks, cakes, white bread. But it’s not for the reason most people assume.
You see, these foods aren’t a problem because they contain cholesterol. The real issue is sugar.
When you take in more sugar than you need, your liver quietly converts the excess into triglycerides – the fatty cargo loaded into those oversized ‘lorry’ particles we spoke of earlier (chylomicrons and VLDLs).
The more sugar you eat, the more triglycerides your liver makes. And that means more lorries on the road – and more cholesterol-rich remnants left drifting in your bloodstream once the deliveries are done.
Saturated fats create similar behaviour in your liver, which is why doctors tend to push a familiar swap: less butter and red meat, more Mediterranean-style fats. “Avocado, walnuts, olive oil, oily fish,” recommends Dr Zoe Astroulakis, consultant cardiologist at New Victoria Hospital in London.
“And your plate should be much more full of pulses, legumes, fresh fruit, vegetables and protein than carbs.”
Astroulakis is also a big fan of overnight oats that have “been allowed to sit in something, whether it’s skimmed milk, water, almond milk or oat milk” for their cholesterol-zapping power.
The soaking is key: it releases a fibre called beta-glucan, which forms a thick, sticky gel as it moves through your gut. That gel acts like a sponge, mopping up cholesterol before your body can absorb it and sweeping it out of your system.
Your liver, suddenly short on cholesterol, has to pull more from your bloodstream to compensate – bringing your overall levels down in the process.
2. Moderate your alcohol
Here’s one that might sting. Alcohol is another driver of triglyceride production – when you drink, the liver converts more fatty acids into triglycerides, which means more of those large particles are dispatched and more remnants are left behind.
So how much is too much? The honest answer: less than we used to think. The latest US dietary guidelines have dropped specific daily limits altogether, replacing them with a simpler message – drink less for better health. The World Health Organisation has gone further, concluding there is no safe level of alcohol consumption at all.
As Astroulakis says, “There’s no safer level than zero.”
3. Maintain a healthy weight
It’s no secret that carrying excess weight is bad for your heart. What’s less obvious is how directly it feeds into remnant cholesterol.
As fat cells grow – which they do when we gain weight – they start leaking triglycerides into the bloodstream. To deal with this overflow, the liver ramps up production of – you guessed it – chylomicrons and VLDLs, those large lorry particles used to ferry the fat around. Cue more cholesterol-rich remnants.
At the same time, excess weight is closely tied to insulin resistance. That dulls the activity of the enzymes responsible for clearing these remnants away. So not only are more lorries being sent out, fewer are being cleared.
“We see that with patients who are very obese – they often have very high remnant cholesterol and triglyceride levels,” says Riyaz Patel, professor of cardiology at University College London. “And we know those levels can come down as they lose weight,” whether through diet, exercise or medication.
One caveat worth knowing: BMI – your weight divided by your height squared – isn’t the whole picture. Someone with a perfectly ‘normal’ BMI can still carry high levels of visceral fat, the deeper fat that wraps around your organs and is particularly associated with elevated remnant cholesterol.
In other words, you can look healthy on the scales while your risk is quietly building – something only a blood test will catch.
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