Until now, little had been known about the impact obesity has on the immune system as it attempts to fight off cancerous tumours
By Liz Farsaci for www.dublinlive.ie
A new link between obesity and cancer has been discovered by scientists at Trinity College Dublin, it was announced on Monday.
The body’s immune system can fail in the presence of excess fat, reducing its ability to fight cancer and other diseases, the research found.
The study confirms why the body’s immune system – led by cancer-fighting “Natural Killer” cells – stutter and fail in the presence of excess fat.
The link between obesity and health issues such as Type 2 diabetes, cardiovascular disease, and a range of infections is well known, as is the link between obesity and up to 50% of certain cancers, including liver, kidney and skin cancer.
But until now, little has been known about the impact obesity has on the immune system as it attempts to fight off cancerous tumours.
Through working with humans cell samples and mice, scientists discovered that the Natural Killer cells – white cells that are the body’s first line of defence – get clogged up by excess fat in people who are obese.
This clogging up then prevents Natural Killer cells from getting fuel from lipids, or fats, so they don’t have the energy to kill tumour cells.
At the same time, tumour cells can take in energy from lipids, helping them to grow rapidly, says Prof Lydia Lynch, Associate Professor in Immunology at Trinity College Dublin, who led the research.
“So obesity is a double hit,” Prof Lynch told the Irish Daily Mirror. “Obesity can fuel the tumour, and it can inhibit the anti-tumour response.”
The findings are crucial in the fight against cancer as obesity levels continue to rise in Irish adults and children, says Prof Lydia Lynch.
“Despite increased public awareness, the prevalence of obesity and related diseases continue,” said Prof Lynch.
“Therefore, there is increased urgency to understand the pathways whereby obesity causes cancer and leads to other diseases, and to develop new strategies to prevent their progression.
“Regular treatments may not work in the same way for obese people, and so we need to understand exactly what’s happening to the tumour and to the immune response in obese people,” added Prof Lynch, who also conducts research at Harvard Medical School and Brigham and Women’s Hospital in the US.
The research has just been published in leading international journal Nature Immunology.
Ireland has one of the highest rates in Europe, with one in four adults now classed as obese, while 22% of nine-year-olds are overweight or obese.
A study from the ESRI and Trinity College Dublin revealed at the weekend that 17% of children were overweight and 5% were obese.Only a quarter of nine-year-olds reached the recommended level of physical activity which is at least 60 minutes every day.