The Gut Microbiome: What It Is and Why It’s Important

What exactly is the gut microbiome?

The gut microbiome consists of trillions of microorganisms including viruses, bacteria and fungi which live along the digestive tract. We hold ten times more bacteria cells than human cells! The colonisation of the gut is initiated at birth and is influenced throughout life by a number of environmental factors, including; route of delivery, exercise, stress, alcohol, smoking, environment, sleep and diet. Throughout life the gut microbiota changes in response to environmental and lifestyle factors, making each of our gut microbiota completely unique.

Why is the gut microbiome important?

The gut microbiota influences numerous processes which occur within the body. These processes include: hormone production such as melatonin (the sleep hormone) and serotonin (the happy hormone), energy metabolism, the absorption of key nutrients and excreting waste products to name a few. Over recent years evidence has emerged to demonstrate the vital importance of the gut microbiome in managing health and disease.

The role of the gut in supporting digestion

A key role of the gut microbiome is to support digestion. The body is unable to digest certain types of fibre, such as resistant starch, lignins and non-starch polysaccharides. Consequently, the gut microbes do digest these. As these fibres are digested these microbes produce short chain fatty acids (SCFAs) which play a number of roles to support overall health. These include; reducing inflammation and maintaining the integrity of the gut barrier in order to prevent unwanted substances and pathogens passing into the bloodstream. SCFAs also help to stimulate satiety hormones in order to prevent over eating and inhibit the growth of the pathogenic bacteria (otherwise referred to as the ‘bad bacteria’). Additionally, SCFAs have also been found to help prevent gastro-intestinal dysfunction and support optimal nutrient absorption.

The role of the gut in supporting mental wellbeing

In more recent years, evidence has emerged to suggest that the gut and brain communicate with each other via the gut-brain-axis. The gut has been shown to produce neurotransmitters which send chemical messages to the brain via the Vagus nerve. As a result, the gut is often referred to as the second brain. Consequently, there is a significant relationship between the gut bacteria and mental health, anxiety and depression. Stress levels can also have a negative impact on gut health and therefore managing the production of cortisol is integral to supporting gut health. Furthermore, as mentioned above the gut is a primary site for secreting the happy hormone serotonin and low levels of this hormone can contribute to low mood.

The role of the gut in supporting immunity

70-80% of the body’s immune system is located in the gut therefore the gut microbes also play an important role in immunity. Some research has shown that specific types of bacteria within the gut can induce diverse immune cells which can impact the whole immune function, not just those cells which are located in the gut. As a result, looking after your gut bacteria is fundamental for supporting a healthy immune function.

The role of the gut in supporting sleep

Evidence suggests the short chain fatty acids produced by the gut microbiota can influence the central and hepatic clocks which in turn can affect sleep duration. Evidence highlights that disrupted sleep and delayed sleep latency (i.e. the amount of time it takes to fall asleep) has been associated with dysbiosis and the overgrowth of specific bacterial species. Looking after the gut microbiome can contribute to supporting healthy sleep. The general recommendations are to aim for 7-9 hours sleep per night.

The role of gut diversity in supporting our overall health

The very basics to aiding a healthy gut is ensuring gut diversity. Having a diverse gut microbiome essentially means that the good bacteria in the gut span across a number of different beneficial species. In addition to this, a good diverse gut profile also requires higher levels of beneficial bacteria than pathogenic bacteria. An imbalance between the good and the bad pathogens is referred to as dysbiosis. Low gut diversity, i.e. a narrow range of bacteria species within the gut has been associated with an increased risk of obesity, inflammatory bowel disease and Chron’s disease to name a few.

Evidently, the gut bacteria can play a significant role in supporting digestion, sleep, mental wellbeing, immune function and overall health. For more information on how to support a healthy gut read our article on Optimising The Microbiome Through The Diet.

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The Gut Microbiome: What It Is and Why It’s Important