‘Good’ cholesterol isn’t so good after all: Scientists find the fat may raise risk of life-changing condition

So-called ‘good’ cholesterol may not be so beneficial after all and could even leave you blind, concerning research has suggested. 

High-density lipoprotein cholesterol (HDL), has long been considered good because of the swathe of evidence showing it protects the heart. 

It removes cholesterol from the arteries and carries it to the liver to be broken down and removed from the body — reducing the risk of heart attacks and strokes.

But some research has since started to challenge the view that more is better.

Now scientists, who tracked almost 7,000 Brits, found higher levels of HDL actually raised the risk of the incurable eye condition, glaucoma. 

They were 10 per cent more likely to develop the condition, which can lead to vision loss, compared to those with the lowest levels. 

By contrast, participants with the highest levels of low-density lipoprotein (LDL) cholesterol — typically considered harmful — were 8 per cent less likely to develop glaucoma. 

Yet, the risk was only observed in those over the age of 55, the researchers from Sun Yat- sen University in southern China, said.  

Writing in the British Journal of Ophthalmology, they added: ‘HDL cholesterol has been regarded as the “good cholesterol” for seven decades. 

‘However, this study demonstrates that high levels of [it] are not consistently associated with a favourable prognostic outcome. 

‘This could prompt a re-evaluation of lipid management strategies in patients at risk for glaucoma. 

‘Further studies are needed to investigate the mechanisms behind these associations.’

Cholesterol is a fatty, waxy substance found in the blood that is vital for bodily functions including digestion, making vitamin D and hormones.

However, too much can build up in the blood due to eating fatty food, not exercising enough, being overweight, smoking and drinking alcohol.

Having high LDL cholesterol doesn’t trigger any symptoms but can lead to blocked blood vessels and raise the risk of heart problems and strokes. 

In the study, researchers quizzed over 400,000 Brits aged 40 to 69 on their health history. All also had blood tests including those to measure blood fats.  

Over a follow-up of 14 years, 6,868 (almost 2 per cent) developed glaucoma. 

Compared with participants who didn’t develop glaucoma, those who did, were more likely to be ex-smokers, statin takers, and had diabetes, high blood pressure or cardiovascular disease. 

But analysis of the blood test results showed that higher levels of ‘good’ HDL cholesterol specifically, were associated with a heightened risk of glaucoma.

Every increase in HDL levels was ‘associated with a 5 per cent higher risk’, they added.

The scientists also acknowledged the study had some limitations, including using just the one blood sample from each participant. 

This ‘might not accurately capture individuals’ typical lipid levels,’ they noted. 

But the findings build on previous research which has suggested there may be a link between high cholesterol levels and the increased glaucoma risk. 

Glaucoma is usually caused by fluid slowly building up in the front part of the eye, which increases pressure inside it.

As a result, the optic nerve, which connects the eye to the brain, becomes damaged.

Around 700,000 people in the UK and more than 2million in the US are living with glaucoma, which is usually symptomless in its early stages.

It mostly affects those in their seventies and over, but people of any age can get it.

Eye pain, blurred vision and vomiting are all tell-tale signs of an incurable condition known as the ‘silent thief of sight’.

However, the symptoms of glaucoma, which affects two per cent of over-40s in the UK, can vary considerably.

They can range from cloudy vision and teary eyes to vomiting. 

Glaucoma, which develops slowly over many years in most cases, can lead to a loss of vision if not treated promptly. 

Treatment aims to lower this pressure through prescription eye drops, oral medicines, laser retreatment, surgery or combination of these options.