Bacteria don’t have the best reputation. They tend to be synonymous with germs, infection and disease – things we can catch from our external environment that make us sick. Things we make every effort to avoid contact with.
Bacteria have been sorely misrepresented. While there are nasty strains, many species of bacteria are much more a part of us than we realise. Our bodies are absolutely swarming with these single-celled organisms. The bacteria that dwell on and in our bodies, our microbiome, are, for the vast majority, not only harmless, they may even be helpful.
Our gut is home to our most abundant bacterial ecosystem – 99 percent of our body’s bacteria live in our gut. While it was previously believed by scientists that each person’s gut contains the same types of bacteria, we now know that this is not the case. There are more than 1000 different species of bacteria that can live in our gut, about 100 trillion microbes that can weigh up to 2kg, and our individual stock can vary greatly.
The gut microbiome has an intimate relationship with our immune system. 80 percent of our immune cells are in our gut and these cells take advantage of bacteria to protect us from pathogens. The good bacteria in our gut know to occupy any free space that would otherwise be left for harmful microbes to colonise. Some bacteria in the gut also help to make our immune system more tolerant, which results in a milder immune system response to irritants that may otherwise cause an allergy-type reaction.
Not only are bacteria an important part of our bodies, a lack of the right types of bacteria in our body may actually cause health issues. Imbalanced levels of bacteria in our gut have been found in people suffering from obesity, malnutrition, neurological diseases, depression, chronic fatigue syndrome and chronic digestive problems.
Just as our outside environment influences our health, so does the microscopic world living within us. A healthy stock of vitamin B producing bacteria can increase a person’s energy levels. Too much of a certain type of bacteria in the gut may increase a person’s tendency to gain weight from the food they eat. Supplementing with probiotics has been shown to give positive results to people suffering from irritable bowel syndrome and some food allergies.
Some studies performed on mice have shown that the expression of our health is largely dictated by the bacteria that live within us. Mice with too few bacteria in the gut are susceptible to infection by relatively harmless pathogens. They were also hyperactive, lacked a sense of caution, ate more and took longer for their food to digest. Those fed bacteria from mice with type II diabetes soon developed problems metabolising sugar. It is becoming increasingly clear that the nature of the creatures that live in our bodies make a significant difference to our overall health. And while microbiome research is still young, it seems bacteria make a hugely healthy contribution to our lives.