Gut Flora

Specific Health Concern 18 December 2017


Discovering your gut flora…

The bacteria that live in our gut play an important role for our health and this article uncovers the functioning of this gut flora for a better understanding.

Article written by Ariane Monnami, nutritionist with degrees in Micronutrition and Neuronutrition.


Bacterial colonisation

Did you know? We have more foreign cells in our body than ones of our own!

Our gut contains around 100,000 billion bacteria, between 10 to 100 times more than the number of body cells.

Our gut is home to over 1000 types and 35,000 strains of different bacteria, distributed in a variety of ways according to the individual and the location within the gut. These bacteria therefore represent a person’s very own individual footprint, influenced by different factors: birth delivery method, diet, stress, antibiotics and pollution.

We can identify three categories of gut flora:

            – Dominant endogenous flora, contributing to 90% of anaerobic bacteria   (those that don’t require oxygen for growth)

            – Subdominant endogenous flora (including Lactobacilli).

            – Active gut flora, including bacteria that can turn into pathogens if their              proportion increases abnormally.


Friendly bacteria

In medical terms, we speak of ‘saprophytic’ bacteria – otherwise known as friendly bacteria which live in harmony with our bodies. 

What makes this bacteria so ‘friendly’? Well, our gut flora protects us against all kinds of intruders such as pathogens, fungi and viruses. It is also able to synthesise enzymes for digestion as well as provide us with essential vitamins: vitamin K, B5, B8 and B12.


What is gut flora made of?

The close link between mother and child

During natural childbirth, the child swallows a small amount of liquid found in the mother’s genital area. The bacteria present in this liquid will start to make their way to the child’s intestine and need only a few days to start making their own vitamin K. It is for this reason that vitamin K drops are also given to new-borns.

Birth by caesarean section – what are the effects on bacterial colonisation?

When born by caesarean, bacterial colonisation does not occur and as a result, gut flora formation is slightly compromised. However, breastfeeding can potentially get all of this complicated gut story ‘back on track’.


How can gut flora be damaged?


Only a few days of antibiotic treatment can be enough to cause gut flora imbalance and naturally, the longer and more frequent the treatment, the greater the problems caused.

Dietary imbalance

Whether it be too much fibre, too much meat or too much sugar, any dietary imbalance can also cause gut flora imbalance and have undesirable effects such as bloating, diarrhoea or constipation.


Gut flora and immunity

The bacteria present in our gut modify the functioning of the immune system in order to:

            – Fight against infectious pathogenic agents

            – Discourage food intolerances 


Gut fora and obesity

Recently, studies have shown strong links between gut flora and obesity, with bacteria variety amongst slimmer individuals differing from that found in overweight individuals. However, it nevertheless remains difficult to take a therapeutic approach towards this issue.


Gut flora – a second brain?

We often hear that our gut is our ‘second brain’ – the gut most importantly produces serotonin, a natural neuromodulator and anti-depressant.

Any sort of disruption in the functioning of our gut can therefore also have psychological effects.


The role of probiotics

According to Reid, “Probioitics are microorganisms administered in an active state and produce many beneficial effects on the health and well-being of the host”.

The most well-known probiotics are lactic bacteria (lactobacilli, streptococci and lactococcus) as well as bifidobacteria. 

Depending upon the strain, probiotics can have effects on the following:

            – Intestinal transit: diarrea, constipation and bloating

            – Immunity

            – Allergies



GRANGETTE C – Probiotiques et immunité. Probiotiques et régulation de la réponse immune allergique et inflammatoire. Cah. Nutr. Diet. 2007 ;42(2) : 2S76-85.

[HEYMAN M – Probiotiques et immunité. Effets des probiotiques sur le système immunitaire : mécanisme d’action potentiel. Cah. Nutr. Diet.2007;42(2):2S67-75.