AN ILLUSTRATIVE VIEW OF THE GUT MICROBIOME
Factors Influencing the Gut Microbiome
Geography
Where we live in the world can have a big impact on our gut microbiome. This is largely due to the different types of food available.
Different gut microbiomes are identified across the world.
In developing countries such as Malawi, a diet high in fibre and carbohydrates is seen. These compounds influence the expression of genes in our gut bacteria resulting in increased expression of genes involved in carbohydrate digestion and vitamin synthesis. In comparison, gut bacteria in developed countries such as the USA tend to have reduced gene expression for these processes due to a diet higher in fat and protein.
Diet
Vegetarian
Omnivore
Vegetarian diets tend to be high in fibre and carbohydrates and so resemble a similar gut microbiome as seen in developing countries such as Malawi.
A regular omnivore diet tends to be higher in fat and protein and therefore resembles a similar gut microbiome as seen in developed countries such as the USA.
The gut microbiome changes depending on our diet
Pharmaceutcals
Before antibiotics
After antibiotics: Damage to the protective barrier leaves the gut susceptible to infection
After probiotics: The gut is repopulated with beneficial bacteria
Antibiotics
Antibiotics are medicines prescribed in the case of a bacterial infection. They work to target pathogenic bacteria; however, antibiotic target spectrums are broad, meaning commensal bacteria in the gut are also affected.
The effect on the gut bacteria can lead to loss of the protective barrier leaving the gut susceptible to bacterial invasion through epithelial cells lining the gut.
Probiotics
These are derived from traditional fermented foods such as yoghurt, or from human origin and incorporated into foods, nutritional supplements or pharmaceutical products. They are used to balance the gut microbiota, prevent a secondary infection after antibiotics and improve symptoms seen in irritable bowel syndrome.