The microbiome and gut health

The human microbiota consists of the 10-100 trillion symbiotic microbial cells harboured by each person, primarily bacteria in the gut; the human microbiome consists of the genes these cells harbour. A typical digestive tract contains a vast collection of microbial communities, including:

The gut contains more than 1000 bacterial species. And that’s a good thing, because a diversity of bacteria in the gut is associated with stability and resilience, which is a reliable indicator of gut health. And, interestingly, research has shown that the composition of the gut microbiome can change with dietary intervention, stress levels and quality of sleep.

Based on the recent advances in the area, a paper published by Berg et al on June 30th 2020 recommends the revival of the original definition of the microbiome term suggested by Whipps et al. Berg et al explain that, ‘The definition, which contains all important points that are valid even 30 years after its publication in 1988, was extended by two explanatory sentences differentiating the terms microbiome and microbiota’:

Definition of Microbiome

The microbiome is defined as a characteristic microbial community occupying a reasonably well-defined habitat which has distinct physio-chemical properties. The microbiome not only refers to the microorganisms involved but also encompass their theatre of activity, which results in the formation of specific ecological niches. The microbiome, which forms a dynamic and interactive micro-ecosystem prone to change in time and scale, is integrated in macro-ecosystems including eukaryotic hosts, and here crucial for their functioning and health.

Definition of Microbiodata

The microbiota consists of the assembly of microorganisms belonging to different kingdoms (Prokaryotes [Bacteria, Archaea], Eukaryotes [e.g., Protozoa, Fungi, and Algae]), while “their theatre of activity” includes microbial structures, metabolites, mobile genetic elements (e.g., transposons, phages, and viruses), and relic DNA embedded in the environmental conditions of the habitat.

Gut microbiota are unique to each individual. Their composition is influenced by various factors – some of which we can control, and others we can’t.

For example, when a baby is born, the delivery method can influence maternal-offspring exchanges of microbiota. In the womb, if the unborn baby is exposed to antibiotics, this can also affect their gut microbiome.

Throughout life, people can support the balance of their gut microbiome by making healthy lifestyle choices, such as the food they eat and how much exercise they get.

For more information about factors that influence the balance of the gut microbiome.

In healthy bodies, the gut microbiota perform a number of key functions:

When the microbiome becomes imbalanced, this is known as ‘dysbiosis’ and can be defined as:

An increase in potentially harmful microbes

Loss of microbial diversity

Loss of beneficial microbes

Dysbiosis can be implicated in the pathophysiology of gastrointestinal disorders and other metabolic conditions.

What causes dysbiosis?

Dysbiosis may be caused by medication (e.g. antibiotics) bacterial infections (e.g. gastritis) stress and lack of sleep.

Unlike with other organs of the body, communication between the gut and the brain appears to be a two-way affair. This two-way communication is believed to occur via various routes.

The gut contains more than 1000 bacterial species. And that’s a good thing, because a diversity of bacteria in the gut is associated with stability and resilience, which is a reliable indicator of gut health. And, interestingly, research has shown that the composition of the gut microbiome can change with dietary intervention, stress levels and quality of sleep.

There are various lifestyle factors that can influence the health of the gut microbiome. These include: