The Importance of Bacteria

29/08/2014

Gut bacteria are also known as gut flora or gut microbiota, with the metabolic activities performed by these bacteria resembling those of an organ.  In fact, around 100 trillion micro-organisms can be found in human intestines, a number ten times greater than the total number of human cells.  While scientists have long understood the important role that bacteria plays in the gut, recent studies have brought a new understanding of just how important balanced bacteria levels really are.

After studying the trillions of bacteria that populate the gastrointestinal tract and how they influence allergic responses to food, Dr Simon Keely, senior lecturer in immunology and microbiology at the University of Newcastle, came to the conclusion that changing gut bacteria is key in the prevention of life-threatening allergies.  “These findings are a game changer for understanding how allergies develop,” said Keely, who found that an increased use of antibiotics could disturb the harmony between bacteria and the immune system of the gut.  

The bacteria living in your gut may also directly affect the size of your gut, with numerous studies linking unhealthy levels of certain bacteria to obesity and high cholesterol.  According to researchers at the Alimentary Pharmabiotic Centre at University College Cork (UCC), a protein commonly made by gut bacteria is able to break down bile acids, reduce cholesterol, and control weight gain in mice.  Unbalanced levels of gut bacteria have been linked to overly-processed foods typical of Western diets, with both obesity levels and allergic conditions higher in countries with more access to processed food products.

“We reasoned that in the gastrointestinal tract that if bacteria influence bile acids, they might have an influence on the host’s [mouse] weight gain and metabolism,” said Dr Cormac Gahan from UCC, adding “So we went about looking at it experimentally and we basically showed if bacteria can break down bile acids then it influences weight gain in mice.”  With obesity becoming more of a problem every day, healthy gut microbiota communities could potentially play an important role in future weight loss programs alongside diet and exercise.

In an even more amazing connection, a healthy balance of gut bacteria has also been linked to mental health.  Along with breaking down indigestible compounds and defending against microbes, our gut also acts as a second nervous system.  This two-way process is sometimes called the 'gut-brain axis', a concept which helps to explain the hard-to-quantify but impossible-to-ignore 'gut feeling' experienced by so many.  It seems our gut bacteria influences the activation of genes important for brain function, while also playing an essential role in the growth of neurons, especially during pre-natal development.

Professor Tom Borody is an Australian doctor who has been championing the treatment of faecal microbiota transplantation (FMT) for 25 years.  Borody claims he is curing incurable diseases using an all-natural waste product we literally flush away - human stool.  While this might not be very nice to think about, Borody claims he has treated Crohn's disease along with a number of auto immune and neurological diseases.  While his claims are controversial, according to the ABC, two of Australia's biggest teaching hospitals are embarking on a large national trial based on FMT, as more people realise just how important gut bacteria is for human health.