The harmful fat in blood

Dr. Emanuele Di Angelantonio

As well as cholesterol, we also have fats in our blood called triglycerides. For years scientists have been uncertain about whether these fats cause heart disease.

Research part-funded by the BHF has settled this controversy. The blood fat that gets most attention is cholesterol but University of Cambridge researchers have improved our understanding of another group called triglycerides that also affect heart health. 

These energy-rich fat molecules are naturally produced by the liver but can also come from eating certain types of fat-rich food.

Triglycerides and heart disease

Scientists have known for some time that high levels of triglycerides are associated with heart disease but, despite this, research had not found conclusive proof that high levels could be causing disease. Dr Emanuele Di Angelantonio and his colleagues at Cambridge decided to look for an answer by analysing the results of over 100 of these studies using what’s called a ‘meta-analysis’.

“By doing a meta-analysis, we could combine the results of lots of different studies to get some certainty where individually these studies had not produced significant results about the importance of triglycerides,” explained Dr Di Angelantonio. With his colleagues he looked at data from studies that assessed the impact on triglyceride levels and risk of heart disease of having a particular version of a gene. “We focused on a variant of a gene, called APOA5, known to influence triglyceride levels,” said Dr Di Angelantonio.

This variant causes increased triglyceride levels in the blood. “People with this variant had an 18 per cent greater risk of heart disease than people without the variant of APOA5,” added Dr Di Angelantonio.

What's next for research?

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The results indicated that triglycerides were causing heart disease but it was not exactly clear how. “More research is needed to show whether action to reduce levels of triglyceride in the blood actually reduces the risk of heart disease,” said Dr Di Angelantonio. This would involve doing large clinical trials over extended periods of time.

These kinds of meta-analysis studies, where lots of different sets of results are looked at together, are important because they allow researchers to see clearer pictures than they might get from just one study. Similar work done by BHF Professor Sir Rory Collins led to large scale clinical trials, funded by the BHF, which showed the effectiveness of statins. Many lives are being saved already by people taking these drugs to reduce their cholesterol level. Perhaps in the future more people will take drugs similar to statins that reduce their triglycerides to reduce their heart disease risk.

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