Gut Bacteria and Immune Function

Gut health and gut microbiome have become massive talking points in recent years. Microbiome is another word for the bacterial colony that live in the gut synergistically with us. We provide them a safe and fertile environment in which to flourish, they provide us with a list of health benefits now becoming as long as your arm. They really do seem to deliver an effect on almost every physiological system to some degree or another.

One role that our gut flora plays that is only just becoming clear, but is looking to become a very exciting field of study indeed, is the influence that our gut flora can have upon our immunity. There certainly isn't an absolute and definitive picture of this yet as research is in its infancy, but a few key elements have become clear.

Our gut flora has a part  to play in immunological development

It is becoming clear hat there is a role for gut flora to play in the development of our immune system from birth. It was once thought that when we were born, our digestive tract was almost a sterile environment that had to be populated and given the opportunity to flourish. However, in recent years as analytical methods have improved, we now know that we are born with a pre formed bacterial colony, and that develops in utero and many commensal bacteria are found in the placenta.

We are born with an immature immune system that has to develop and grow. This is why we get every illness under the sun as kids as our immune systems need to be exposed to a wide variety of pathogens in order to develop responses for these. When we are born, we have a basic set of immune responses, but there are some types of cell that still need to grow and mature, and it is at this level that the gut bacteria are believed to offer a helping hand. Animal studies using mice found that mice that had a sterile digestive tract had under developed immune systems, but when they were given even a restricted level of bacteria to their digestive tract, their immune systems developed fully.

Our gut flora helps the immune system make better decisions

At every point of our life, we are exposed to hundreds and hundreds of different things via the food we eat, the air we breathe. If we reacted to every single one of this stimuli, we’d pretty soon be dead! Our immune system needs to develop a tolerance to most things in our environment, and be able to fully identify pathogenic influences that truly can be a problem to us. We have to be in a state of balance between tolerance and reaction. A very wide and diverse gut flora that is made up of many types of microorganism help to show the immune system what type of micro -organism will likely do us harm, and what types wouldn’t.

There is ‘cross talk’ between gut flora and cells of the immune system

This is where much of the newer research has begun to look, and this is the area that is the most fascinating. It seems there is dialogue between the bacteria that live in our gut, and the cells of the immune system. Our digestive tract is awash with immune activity, as it is such an easy entry route for pathogens. The gut wall is studded with patches of tissue called peyers patches. These are basically like surveillance stations that are continually monitoring gut contents and reporting this back to the rest of the immune system. If a pathogen comes along, the cells that dwell in the peyers patches detect whats going on and relay the relevant information back to the rest of our immune system so that it knows what the threat is and how to respond to it.

It now seems that via such immunological tissues as the peyers patches, the gut bacteria and the immune system can enter a conversation. The gut bacteria can stimulate certain responses and the immune system can talk back to down regulate other responses. There have already been links between these types of communications and celiac disease processes, inflammatory bowel disease, and even obesity. This IS in its early stages and specific conclusions around these diseases cannot be arrived at yet, but the early signs are truly fascinating.