We are actually more bacteria than human! Trillions of microscopic organisms, or microbes, call the human body home; the traditional estimate is that the average human body is inhabited by ten times as many non-human cells as human cells, but more recent estimates have lowered that ratio to 3:1…….you are 3 times more bacteria than human!!
Here's a wonderfully clear explainer video by The Conversation (theconversation.com), taking you the basics of the the human microbiome.
We’ve actually known for a long time that the human body is teaming with microscopic organisms, research showed bacteria in the mouth as early as 1600s. However the phenomenon of a link between our microbiome and overall health is a relatively new area of study.
While the research is still in its infancy, the microbiome has been linked to everything from obesity, asthma and allergies to autoimmune disorders, such as rheumatoid arthritis and diabetes.
The microbiome also influences how our brain functions and is linked to conditions such as depression, anxiety and stress. These links explain why there is now a growing trend on creating or maintaining a healthy gut. And a healthy human gut consists of several thousand types of bacteria as well as other microbes, though some types will be more common than others.
The exact composition of someones microbiota is unique and it is constantly changing. It depends on what you eat where you live, who you live with, what you touch and even how you’re born.
Before you are born we have very little, if any, microbes inside us, microbes really start to colonise our bodies the moment we are born. The way we are born, either naturally or by cesarean, influences the type of microbes we first contact and hence the types of microbes that will first colonise our bodies. Babies born naturally come into contact with microbes found in the mother's intestinal and vaginal fluids. Whereas in a caesarean birth babies tend to be colonised by microbes typically found on the skin and in hospitals. Similarly babies breastfed will have a different microbiota profile than those that are formula fed.
From the day we are born our microbiome evolves quickly and reaches maturity during the first 2-5 years. After that it stabilises resembling that of an adult.
As an adult changes to our microbiota are likely to be small, but major shifts in composition can occur when we radically change our diet or take antibiotics, which kill bacteria. Significant life stages such as puberty pregnancy and menopause causes large changes to our microbiome and as we get older our microbiome ages too, and the number of microbes species decreases.
Since most microbes are in our colon or large intestine, what we eat feeds our microbiota, and what a healthy microbiota needs are fibre rich complex carbohydrate (CHO). Additionally the microbiota provide essential vitamins we can’t make ourselves, such as b vitamins.
Perhaps most important of all, the microbiota helps our immune system develop effectively, training it to differentiate between good microbes and bad pathogens that cause disease.
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