An Introduction to the Human Microbiome by Elizabeth Bolam

There has been a lot of talk recently about gut bacteria, intestinal flora and the microbiome, but what does it all mean and why is it now being acknowledged as a major contributor to our health?
The human microbiome includes all of the microbes (bacteria, viruses, fungi, protozoa and helminths) that populate our skin, ears, nose, mouth, throat and intestinal tract. We have on average 10 trillion cells in the human body. The number of microbes inside us, on our skin and in our “nooks and crannies” outnumbers our human cells by a factor of about 10:1. Meaning there are in excess of 100 trillion microbes living on us and in us. This has led many to question whether we are in fact human or a colony of microbes in the shape of a human! The diversity and number of microbes in our gut plays a large role in determining whether we are healthy or suffering from ill-health.

So how do we develop our microbiome?

When we are developing in our mother’s womb we are largely free of any microbes. It is during the birth process, as we pass down the birth canal and out into the world, that we are inoculated through our mouth and nose and all over our body with our first microbes. We inherit our microbiome largely from our mother at this time. If our mothers’ microbiome is not healthy then we will not be inoculated with the ideal microbes for a healthy life. A baby born by caesarean misses out on this exposure to her mother’s microbes and instead will be largely inoculated with microbes from the hospital environment which are frequently not ideal for the development of a healthy microbiome. A baby’s immature microbiome will develop with a health giving profile or a health depleting profile according to a myriad of factors such as; whether they are breast fed, the number of courses of antibiotics they are given in their infancy or childhood, medications they are prescribed, the foods they are introduced to, how dirty or clean their environment is and the chemicals they are exposed to.

The balance and diversity of the microbes you have in your microbiome will ultimately determine the level of health or disease you experience. An over growth of pathogenic or “bad” microbes can cause a plethora of symptoms from gastrointestinal issues to autoimmune diseases to depression and anxiety. While I am referring to the microbes as either “good” or “bad”, it is not quite as simple as that. Many of the so called “bad” microbes when in small numbers relative to the “good” microbes have important health giving functions. It is only when their numbers become out of control that they can cause disease.
It is useful to use the analogy of a carpark to explain the microbiome in the gut. There are a fixed number of parking spaces and these can either be filled with a majority of “good” microbes or “bad” microbes. If you take a course of antibiotics for example, and kill a large majority of the microbes in the gut, as the microbiome works to replenish itself, depending on the environment in the gut, the parking spaces will be filled with either “good “microbes or “bad” microbes.

The health of the individual is usually affected when there is an overgrowth of the “bad” microbes compared to the “good” microbes. When rebalancing the gut microbes the aim is to provide an environment that encourages the growth of the “good” microbes and discourages the growth of the “bad” microbes. In this way as the “bad” microbes die off, their parking spot will be taken by the flourishing “good” microbes. A diet high in fibre, low in sugar and processed foods and high in healthy fats, vegetables and fermented food encourages the “good” microbes to flourish. The “bad” microbes flourish on a high sugar, low fibre, low vegetable diet. While diet is one of the main influences on the composition of the microbiome, there are other factors such as stress, sleep, exercise, medications, chemicals in the environment and even your thoughts that can have an effect on the health or otherwise of your microbiome.

Guest post by Elizabeth Bolam
Nutritionist
GAPS Practitioner
RN Div 1

Email: elizabeth@mindbodyvitality.com.au

Phone: 0458 758 706