A 'SPARE tyre' or 'beer gut' can weaken our ability to fight cancer, according to new research.
Researchers at Trinity College found that belly fat can stop cancer-killing cells from working although they are the body's first line of defence against the disease.
Like a sponge, the fat attracts the cancer-fighting T cells, which means they are not going to the site of a tumour, said researcher Dr Joanne Lysaght, assistant professor at the Department of Surgery in Trinity.
The fat around the abdomen is also linked with an increased risk of several cancers, including oesophageal adenocarcinoma, which occurs near the stomach.
This form of cancer has doubled in the last two decades and it is diagnosed in around 300 people annually, the study pointed out.
The details were outlined in 'A Picture of Health', a compilation of Health Research Board-funded research.
Dr Lysaght said: "We wanted to investigate why obesity is so closely linked with this particular cancer. And we found some clues in the immune cells that turned up deep in the obese belly fat."
The team looked at fat samples from 40 patients who had an operation for oesophageal adenocarcinoma and discovered that the fat from obese patients contained high levels of the active T cells.
"We found that about 40pc of the T cells were activated and inflammatory, and these are exactly the types of cells you want to kill a cancer tumour," said Dr Lysaght.
"These T cells could be contributing to inflammation, which is generally linked to cancer, or the obese fat could be acting as a sink for these cells meaning they can't do their job and go and fight the tumour."
This kind of "spare tyre" fat, which builds up around the abdomen, has already been linked to an increased risk of heart disease.
Even those who have a healthy weight overall, but have too much abdominal fat, have been found to be at risk because the fat is packed around the organs in the abdomen.
A separate study found that not getting enough sleep is bad for the heart because it affects the way the body controls blood pressure.
The study led by Prof Jack Janes of NUI Galway tried to explain a long-standing puzzle in health and checked healthy volunteers.
"One the one hand, population surveys show that chronic sleep deprivation contributes to the development of high blood pressure and cardiovascular disease.
"One the other hand, experimental studies indicate that sleep loss has little or no acute effect on blood pressure levels. This appears contradictory, because blood pressure level is a major predictor of cardiovascular health."
In the short term, the body's ability to control how the heart pumps blood around the body could be affected. If this is continued over time, sleep deprivation may cause hardening of the arteries.
This contributes to the development of high blood pressure and other cardiovascular problems.
Another study carried out by Dr Zubair Kabir of University College Cork found a gap is emerging between the general population and vulnerable communities when it comes to smoking.
He found that Polish, gay and lesbian communities in Ireland have double the rates of smoking compared to the general population and Muslims in Ireland.
Enda Connolly, chief executive at the Health Research Board said: "'The Picture of Health' clearly demonstrates how our funding is delivering improvements for people's health, patient care and health service delivery."