When our health gets out of whack, we usually need to stop blaming the universe and refocus on that which we cannot see – our own amazing inner world. The living microbiota inhabiting the human body (about 1000 species collectively called the microbiome) weigh up to 2.72kg, about twice the weight of the average human brain, and exist in their trillions, outnumbering the cells in our whole body.

While getting your head around the reality that you’re a walking, talking bacteria farm swarming from entry to exit is unpleasant, there is good news.

Scientists argue that friendly gut microbes are so deeply involved in our bodily functions, they shouldn’t be considered aliens, especially as they have such a vested interest in controlling how our bodies react to foreign particles – the real alien baddies – such as pollution or potential allergens we breathe in and ingest.

Most microbiota only live 20 minutes in the intestinal tract, and their short lives are spent helping us have a healthy gut. That is the foundation for physical, mental and emotional wellbeing. Thanks to our friendly little aliens we can digest food, synthesise vitamins and ward off infection. Our digestive health is intimately linked to our immune, endocrine, circulatory and central nervous systems.

Scientists are intrigued by how microbiota influence the immune system. In recent decades, autoimmune diseases have been increasing; microbiome researchers say some of this is due to changes in our bacterial ecosystem – processed food diet, explosion of antibiotic use, and decreasing contact with the microbe-packed natural world of plants and animals.

“Our microbiome has changed significantly over the past century, and especially over the past 50 years,” says NYU microbiologist Martin Blaser, who puts much of the blame on widespread use of antibiotics.
"These organisms are part of our developmental choreography. They're part of who we are.
“We’re losing microbes with each generation; they are going extinct. These changes have consequences.”

Recent research on the microbiome has shown that its influence extends far beyond the gut, to the brain. During the past 10 years, studies have linked the gut microbiome to a range of complex behaviours, such as mood and emotion, appetite and satiety, and even learning and memory. Not only does the gut microbiome appear to help maintain brain function, but it may also influence the risk of psychiatric and neurological disorders, including anxiety, depression and autism.

Natural inoculation
Mums pass on a lot more than half their DNA! Good gut health starts with natural birth and breastfeeding. A baby collects their mother’s microbiome as they pass through the birth canal, and in the three to 24 hours after birth, including during breastfeeding. These pioneer bacteria help lay the foundation for an infant’s gut health, and therefore immune system and brain development, and profoundly influence their health through life.

It’s democratic
Gut microbiota interacts with both our innate and adaptive immune systems, directing them how to develop; in turn our immune system can decide what types of microbes we host.
Peaceful inner world
Our good gut bacteria is often thrown off balance, undermining the body's natural front line of defence and leaving it unable to fight off invading bugs. Since 70 percent of the body's immune system lies in the digestive tract, good gut bacteria is key to maintaining not only a healthy digestive system, and minimising unwanted digestive discomfort, but also to strengthen our immunity.

Caring for our inner world
An important source of gut microbial diversity is the number of different plants we eat. Eat a fibre-rich, whole foods diet rich in beans, nuts, seeds, whole grains, fruits, and vegetables, all of which feed good bugs. Fermented foods, like kefir, sauerkraut, kombucha, miso soup, have all been found to boost gut health. Take daily probiotics (from pro and biota, meaning “for life”) – these healthy, friendly flora can improve your digestive health and reduce inflammation and allergy. Limit sugar, processed foods, animal fats, and animal protein – these provide food for unhealthy bugs.Antibiotics, acid blockers, and anti-inflammatories damage friendly gut flora.
The bottom line
We live in a microbial world. Micro-organisms were among the first life forms and are still the greatest biomass on the planet.

Gut health affects every aspect of our physical and emotional being – we really are what we eat. The importance of the human microbiome is clear, as changes to intestinal microbiota have been associated with numerous short and long-term health and disease issues such as:

Poor sleepLack of energyDepression Immunity to seasonal viruses and bacterial infections (colds/influenza/tummy bugs, etc)Intestinal/inflammatory bowel diseases, such as Crohn's and ulcerative colitisAllergic diseases such as eczema, asthma, food allergy and hay fever – all mediated by the immune systemDiabetesObesityAutismCancer.