We have written about it before, but to be honest you might not want to know the details of what is inside your gut. I can tell you, though, that it is very important for your well being. In case you got curious, it is called the gut microbiota, a mix of maybe 100 trillion microorganisms, and can weigh up to 2 kilograms that you carry around with you on a daily basis.
Why not deduct it when you next step on the scale? It should be fair enough.
One third of our gut microbiota is common to most people, while two thirds are specific to each one of us. That is to say that the microbiota in your intestine is like an individual identity card. Not that anyone will use it as such, I wouldn’t think.
A most complex ecosystem
The large number of different microbial communities that can be found in the human gut and their impact on human health and disease is a most exciting new area of research. The gut microbiota contains a vast number of microorganisms from all three domains of life, including bacteria, fungi, and viruses. These interact in a complex way to contribute to our well being. It has long been a dark corner of missing knowledge, but the application of advanced DNA sequencing technology has been of an immense help in starting to better identifying the inhabitants.
The microorganisms in the gut can be broadly divided into prokaryotes (bacteria and archaea), bacteriophages (viruses that infect prokaryotes), eukaryotic viruses, and the meiofauna (microscopically small benthic invertebrates that live in both marine and fresh water environments — primarily fungi and protozoa). Of these, bacteria have been the most extensively studied. The gastrointestinal tract is now considered one of the most complex microbial ecosystems on earth and understanding how the multiple communities interact presents both opportunities and challenges.
And there is a life and death fight between the different kinds of inhabitants. It has long been known that the bacteria in the gut play an important role in both health and disease. It is also now becoming clear that the non-bacterial microbiota interacts in a complex way with the bacterial microbiota to contribute to these processes. The most common viruses in the gut are the bacteriophages. They infect and destroy bacterial cells and also have the ability to transfer genetic material from one bacterium to another, with potentially profound implications for health and disease.
There is a predator–prey relationship between bacteriophages and bacteria that can change the composition of the bacterial microbiota in conditions such as inflammatory bowel diseases. Bacteriophages induce immune responses in bacteria and transmit genomic material into bacteria that may alter their function. It makes them extremely important and we have only started to scratch the surface of understanding what they do.
There is also a fight between fungi and bacteria. Decreases in fungal diversity have been shown to be associated with an increase in healthy bacterial colonisation following probiotic therapy, suggesting niche competition between fungi and bacteria.
But there are disturbing signs
Antibiotics are valuable, potentially life-saving tools that have significantly reduced human morbidity and mortality. Unfortunately, antibiotics may also have unintended consequences from their off-target effects that may increase the risk of many long-term conditions. Recently, a possible link has been detected between antibiotic use in childhood and weight gain—with disruption to the normal gut microbiota considered the most likely cause.
It has also been suggested that over-use of antibiotic therapy might be fueling the dramatic increase in conditions such as obesity, type-1 diabetes, inflammatory bowel disease, allergies and asthma, which have more than doubled in prevalence in many populations. There is evidence that microbiota resilience decreases with each subsequent course of antibiotics and that, once disrupted, the normal microbiota may never recover completely or it may be replaced by resistant organisms.
So be kind to your gut microbiota
Take good care of your gut microbiota. The food you eat can have a profound effect.
Many studies have demonstrated the beneficial effects of prebiotics and probiotics on our gut microbiota. Serving as “food” for beneficial bacteria, prebiotics help improve the functioning of microbiota while allowing the growth and activity of beneficial bacteria.
Present in some fermented products such as yoghurt, probiotics help gut microbiota keep its balance, integrity and diversity. Although authorities are still to be convinced of the cause and effect of individual preparations on the growth of beneficial bacteria to award any of them a health claim status.