The human gut microbiome is the bacterial ecosystem of our intestines. It affects our body’s capability to extract energy from our diet. Currently there is an absence of understanding generally about the importance of the gut microbiome’s role in health and well-being. Research suggests that gut–brain axis, a bidirectional neurohumoral communication system in the human body, functions as a pathway for the gut microbiota to modulate brain function of its host. Finding out more about the gut microbiome could lead to the development of dietary interventions, permitting more control of its functions, consequently preventing diet-related and behavioural disorders.

The microbiome contributes to regulating energy equilibrium and brain development and function. The gut microbiome’s structure and function have also emerged as a novel modifiable factor that can impact the risk of developing metabolic-related diseases and eating behaviour. Nevertheless, we have a rather incomplete understanding of the interactions between potential causal factors of these disorders due to the fragmented and compartmentalised research done so far in this field.

Microbiota means “little living” and is the recent name given to the entire microbial community living in symbiosis with our body. Human beings have clusters of bacteria in different parts of the body, such as in the surface or deep layers of skin (skin microbiota), the mouth (oral microbiota), the vagina (vaginal microbiota), and so on.

Gut microbiota was originally called gut flora. It is the microbe population living in our intestine. It comprises tens of trillions of microorganisms, including at least 1000 different species of known bacteria with more than 3 million genes — 150 times more than human genes. (The adult human body is made up of about 37 trillion cells). Microbiota can, in total, weigh up to 2 kg. One third of our gut microbiota is common to most people, while two thirds are specific to each one of us. In other words, the microbiota in your intestine is like an individual identity card.

How do we create our microbiota?

Gut microbiota development starts at birth. The newborn’s digestive tract is sterile inside the uterus. It is colonised by microorganisms from the mother (vaginal, faecal, skin, breast, etc.), during the delivery. After three days the composition of the intestinal flora is directly dependent on how the infant is fed. Gut microbiota of breastfed babies’ is mainly dominated by Bifidobacteria, compared to the ones nourished with infant formulas. It is now thought by scientists that by the age of 3, microbiota becomes stable, continuing its evolution at an even rate throughout life.

Each of us has a unique microbiota.

  • It always fulfils the same physiological functions and they have a direct impact on our health.
  • It helps the body to digest certain foods that the stomach and small intestine have not been able to digest.
  • It has an important role in the immune system, performing a barrier effect.
  • It helps with the production of some vitamins.
  • It helps to fight aggressions from other microorganisms, maintaining the integrity of the intestinal mucosa.
  • A healthy and balanced gut microbiota is key to ensuring proper digestive functioning.

See more information on the gut microbiome on My New Gut and Gut Microbiota Watch websites.