Your body is like a planet. It is inhabited by trillions of creatures adapted to the various environments provided by different parts of your anatomy.
Every surface of the body exposed to the outside world – including skin, nose, ears, mouth, teeth, lungs, vagina and gut – are potential real estate for microorganisms. Some prefer the intense acidity of your stomach, others the salty moisture of your armpits. Body odour – both pleasant and unpleasant – is produced by bacteria. Most of our 100 trillion resident microbes are bacteria, but we also house viruses, fungi and archaea.
The most densely populated region of the body is the colon or large intestine. This is not surprising because the surface area of your gut is up to 100 times greater than the surface area of your skin. Right now in your colon an estimated 1000 bacterial species are breaking down food, manufacturing vitamins, buffering toxins and keeping harmful infections at bay.
The way we live our lives affects not only the earth and its animals but also the population of microorganisms that call us home. In return, the activity of our microorganisms influences us – our general health as well as our mood, energy levels, immune function, metabolic processes, food intolerances, even our height and weight.
The combined weight of the bacteria that inhabit your body is about 2kg – more than the weight of your brain (1.4kg)! A gram of faeces contains more bacteria than there are people on earth.
No two people have the same microorganisms living on their bodies, not even identical twins. In other words, everyone has a unique microbial identity, just as we have a unique fingerprint. This is one of the reasons why one diet does not fit all.
- When and how do we acquire our distinctive microbial population (known as our microbiota)?
- What role do they play in health and disease?
- Can gut bacteria really make a person thin or fat?
- What is the best way of cultivating a healthy microbiota and how important is this?
If you follow mainstream media and marketing, you’d be forgiven for thinking that you simply need to feed your ‘good’ bacteria with pre- and probiotics, avoid eating junk and add fermented foods to your daily fare. While this is good advice, the situation is far more complicated and nuanced.
For a start, different bacteria behave differently under different circumstances. ‘Bad’ bacteria are not always bad for us and ‘good’ bacteria are not always good. Just as humans behave differently in different situations, so do bacteria.
The other issue is that this is still an emerging area of science. We don’t have all the answers. We don’t even have all the questions. Every day new research hits my inbox. Scientists are in the process of determining what constitutes a healthy microbiome. (The microbiome refers to the genetic makeup of our microbiota but many people use the two terms interchangeably.) Scientists are starting to compile a list of bacteria that seem to be desirable – and the key appears to be diversity. The more different species you carry, the better. But just as restoring a rainforest involves more than adding or subtracting a few species, so too restoring optimal gut health will mean more than simply tweaking our diet to encourage the growth of more friendly bacteria.
Over the ensuing months I’ll answer the questions posed above and keep you updated on the latest research involving our merry microbes.
* To read other HEB’s in the gut series click below: