New research has suggested that "good" cholesterol may not always help people lower their risk of developing heart disease.
A team at Cambridge University, funded by the British Heart Foundation, found that some people with high levels of "good" cholesterol are actually at a much higher risk of getting cardiac problems.
It is hoped the findings could help researchers develop new treatments for combating heart disease, as well as better identifying patients who may be at a much greater risk of suffering heart problems in the future.
Published in the journal Science, the study looked at a specific rare mutation that means people with high levels of good cholesterol - also called high-density lipoprotein (HDL) - are at an 80 per cent increased risk of getting heart disease.
Eating olive oil, fish and nuts can raise levels of HDL and doctors often look use it to determine a person's risk of having a heart attack.
The mutation - SCARB1 - affects around one in every 1,700 people and stops HDL from taking the fat it collects to the liver, where it can be processed. This could then put people at a higher risk of having fat accumulate in the coronary arteries, which prevents blood from flowing to the heart.
This significantly increases the risk of cardiac arrest, which is a life-threatening event. Heart disease is a big health problem in the UK, causing nearly 70,000 deaths every year.
The new findings could also see treatment change, as doctors may be less likely to recommend drugs designed to increase the levels of HDL cholesterol to treat heart disease. Instead, they may favour a more targeted approach, developing a personalised care plan for each individual patient.
Professor Peter Weissberg, medical director of the British Heart Foundation, called the study important as it sheds light into "one of the major puzzles" relating to cholesterol and heart disease; although there is evidence to suggest that HDL reduces heart disease risk, clinical trials on its effects have been disappointing.
"These new findings suggest that the way in which HDL is handled by the body is more important in determining risk of a heart attack than the levels of HDL in the blood," Professor Weissberg said.
"The discovery could trigger further research into the SCARB1 gene to identify new treatments that help prevent people dying suddenly from a heart attack," he added.
Find the nearest Barchester nursing home.