The ‘fat but fit’ paradox – where some people who are overweight have a seemingly healthy metabolism – may be explained by a good blood supply to their fat cells, according to new research funded by the British Heart Foundation.
The research – which suggests encouraging the growth of new blood vessels in fat could offer some protection against heart attacks and strokes – is being presented at the American Heart Association Scientific Sessions in Philadelphia, and has been awarded the best UK abstract at the conference.
Scientists from the University of Leeds have studied a receptor – known as IGF1-R – that plays a role in the growth of new blood vessels. The team showed that the removal of this receptor in cells lining the inside of blood vessels of mice fed a high-fat diet encouraged the growth of new blood vessels into fat. This was followed by beneficial changes to the fat, which may offer protection against heart and circulatory diseases in the long term.
According to the researchers, poor blood supply to fat can switch it into an ‘unhealthy’ state. Under these conditions, the fat cells release inflammatory signals that can promote the development of diabetes, high blood cholesterol and high blood pressure, which can all lead to furring of our arteries – the underlying cause of most heart attacks and strokes.
The researchers believe that blood vessels in fat release bioactive chemicals which encourage the fat cells to ‘brown’. Brown fat burns calories to generate heat, helps to control blood sugar, blood pressure and cholesterol levels, and protects against the furring of arteries.
The researchers now hope to use these insights to help develop drugs which can hijack this process and protect the heart and circulation.
Dr Natalie Haywood, Postdoctoral Research Fellow at the University of Leeds who led the study said: “It’s a myth that you can be overweight and completely healthy – but there may be some truth to the ‘fat but fit’ paradox. People with better blood supply to their fat may be more metabolically healthy and could be protected against heart and circulatory diseases.
The next step is to identify the healthy bioactive signals released by blood vessels so that we can potentially harness them to combat heart and circulatory disease in obesity.”
Professor Metin Avkiran, Associate Medical Director at the British Heart Foundation, said: “All of the cells in our bodies need a good blood supply to stay healthy – and that includes fat cells. If our diets are high in fat, we may risk storing up fat more quickly than our bodies can build new blood vessels.
Fat is an essential part of our diet, but too much of it can cause a wide range of health issues. This research may explain why some people who are overweight are more at risk of heart and circulatory disease than others. It’ll take a lot more research before we have a new drug to keep these fat cells healthy. For most people, with or without obesity, the best medicine will be a healthy diet and active lifestyle.”