This blog is centred around the gut microbiome and the impact it has on our health and wellbeing, both when it’s working properly and when it isn’t.
This page, and those in the drop down menu, are dedicated to explaining a little more about what exactly the gut microbiome is, where it’s found, and what it does, and hopefully provide a bit of background to some of the posts.
Ok. Let’s go!
So, what is our gut microbiome?
Google define ‘gut microbiome’ and you pull up this rather wordy result:
The microbiome is defined as the collective genomes of the microbes (composed of bacteria, bacteriophage, fungi, protozoa and viruses) that live inside and on the human body.
Simply translated, the gut microbiome is all of the genes (i.e. the genome) of all the bacteria that live in your large intestine (see below).
Genes are what makes us identical, and they’re little units of inheritable information that our parents passed on to us, and we pass on to our children. Genes are made of up of sections of DNA, and they’re found on chromosomes; whilst we have 23 pairs of chromosomes (i.e. 46), bacteria only have one. But don’t think this is insignificant. Because there’s so many of them, the genes in our microbiome (that is, the sum of all the different microbes on our body) outnumber the genes in our own genome by about 100 to 1.
Whilst there are other microbes present, such as fungi and viruses, these are far outweighed by the presence of different kinds of bacteria which dominate the intestines. In fact they dominate us – and it’s estimated that there are 10 times the amount of bacterial cells in our body than our own cells, and account for as much as 1.5kg of our overall body mass.
But don’t be alarmed, because being inhabited by so many bacteria is actually beneficial to your health. It’s an example of a symbiotic relationship between bacteria and humans that has likely evolved with us. If you think about it, you’ve probably heard of the term ‘gut bacteria’ or ‘gut flora’ – and specifically that there are ‘good’ bacteria and ‘bad’ bacteria.
Scientists employ slightly more technical, less anthropomorphic terms to describe bacteria , such as mutualistic, commensal, and pathogenic:
- Mutualistic: where bacteria and humans exist in a relationship in which each individual benefits from the actions of the other
- Commensal: an association between bacteria and humans where one of us benefits and the other doesn’t either benefit or get harmed by it
- Pathogenic: a bacteria that causes a human harm or disease.
Ok, great. We know what a gut microbiome is. It’s a shed load of bacteria living in our gut, and the genes they contain.
So what do they do?
The gut microbiome has an enormous range of roles in our bodies:
- In our digestion:
- Extracts energy from food
- Produce essential vitamins
- Regulate metabolism
- In our brains:
- Regulates our appetite and energy levels
- Emotions and attitude
- Response to stress
- Learning and memory
- Response to pain
- In our immune systems:
- Physical barrier against nasty microbes
- Act as antimicrobials
- Stimulation and regulation of our own immune system in both the body and the brain
What they can do and their impact on your body/health is largely determined by the species that you have present. Everyone’s microbiome is different; consider it your bacterial fingerprint. It’s estimated that there are over 1000 different species; however, we do know that there are 4 particular species that dominate and can account for as much as 40% of the total microbiome:
- Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria
More information about what exactly this means for us can be found in the drop down menu branching from this page. 🙂
This video is a little patronising, and it has been endorsed by Danone (who make probiotic yoghurts), but it does cover the most basic points:
Gut anatomy
Confusingly, there are several words used interchangeably that relate to our digestive system. Simply put, our digestive tract, or gastrointestinal (GI) tract, is the route that food follows through our bodies from our mouths to our bottoms, including the digestive organs (stomach, small intestine and large intestine) that they pass through on the way.
The GI tract is split into ‘upper’ and ‘lower’, and it’s the lower GI tract that we’re most interested in when we’re talking microbiome. That’s because the lower GI tract contains the intestines, which are also known collectively as the bowel or the gut.
Zoom in even further, and we find ourselves only really being interested in the large intestine (also known as the colon). This is largely where the microbiome is found.
New roles of the microbiome are being discovered almost every week with the help of scientific research. Keep checking back here on the blog, where I’ll be attempting to keep you up to date with the latest findings.
Enjoy!
Lucinda
Gut Instincts 
