Gut microbiome
A complex community of billions of bacteria, viruses and fungi living in the digestive tract, forming an ecosystem essential to digestion, immunity and overall health.
The gut microbiome (also called gut flora, though the technical term is microbiome) is made up of 100 trillion micro-organisms, more cells than the human body itself. The main players are the Firmicutes and Bacteroidetes bacteria, along with genera such as Lactobacillus, Bifidobacterium and Faecalibacterium.
A fresh angle (2024 study): the microbiome modulates the stress response via circadian rhythms and the HPA axis (hypothalamic-pituitary-adrenal). Dysbiosis sets the stage for chronic inflammation and for disorders of stress regulation. This explains why an unbalanced microbiome is linked to anxiety and depression (Institut Pasteur study, 2023).
The microbiome also affects the skin barrier. An imbalance can aggravate acne, eczema and other skin inflammation, as the gut and skin share the same embryological development. An “in & out” approach (nutrition + skincare) is therefore relevant.
Microbial diversity: more than 1,000 different species = stronger. Moderate exercise (a 30-minute daily walk) increases diversity and favours butyrate-producing bacteria (such as Faecalibacterium prausnitzii and Akkermansia), essential for the integrity of the gut barrier. Rest and meditation are also allies: the gut digests better when calm.