You are treating a patient with burnout, insomnia, persistent fatigue and sugar cravings? You may have already tried everything on the HPA axis, with no lasting improvement.
What if the lever were intestinal?
The link between gut microbiota and stress is now well established1: the microbiota modulates neuromediators, inflammation and the cortisol response.
But how can you act on this concretely, in practice?
In this article, discover the role of the microbiota in chronic stress, and refine your nutritional and micronutritional strategies.
1. Chronic stress, an underestimated physiological imbalance
You know better than anyone: in what patients tell you, the word “stress” comes up often, too often to be taken lightly.
But it is worth remembering that stress is not in itself pathological: it is a normal physiological reaction to an event perceived as destabilising. Everything depends on its frequency and intensity.
Faced with a stressor, the body moves successively through three phases:
The alarm phase: activation of the body’s defences (cortisol, glucose, heart rate, muscle tone)
The resistance phase: adaptation is maintained, at the cost of continuous physiological effort
The exhaustion phase: when resources collapse, giving way to physical, mental and immune exhaustion
In practice: spotting the signs of a persistent imbalance
In patients, chronic stress does not always present as an explicit complaint.
It often shows up as diffuse signs that are easily dismissed, which it is crucial to recognise as linked to disruption of the HPA axis.
Common clinical signsAssociated pathophysiological mechanismsUnrefreshing morning fatigueProlonged cortisol secretionNight-time wakingHPA axis instability and disrupted circadian rhythmAnticipatory anxietySerotonergic depletion and excess noradrenalineSugar, alcohol or tobacco cravingsCompensatory dopamine-seekingMood or concentration problemsLow-grade inflammation, neuromediator deficiency
The key message: prolonged stress does not just wear down your mood. It profoundly disrupts metabolism, immunity and neuroendocrine balance, particularly through overactivation of the HPA axis.
And if action is not taken quickly, rest alone is no longer enough to halt the spiral.
2. Brain and gut, a bidirectional axis
The microbiota is often described as our “second brain”.
But that expression may not go far enough: some argue the gut could even be considered the first. This is because most of the communication between brain and digestive system does not run “from the top down”, but rather from the microbiota to the brain.
According to current data, around 80% of messages travel in this direction, via the vagus nerve (mainly its afferent fibres), the enteric nervous system and a myriad of chemical signals2. These include:
GABA, the inhibitory messenger, whose production is supported by certain bacteria
serotonin, 80% of which is synthesised in the gut
BDNF, a neurotrophic factor involved in neuronal regeneration
dopamine, affected by chronic digestive imbalances
An imbalanced microbiota, whether depleted or inflammatory, therefore directly disrupts the regulation of these neuromediators3. In consultation, this dysregulation can show up as anxiety disorders, excessive rumination, emotional lability or even a depressive state.
The link is therefore genuinely bidirectional: chronic stress unbalances the microbiota, and an altered microbiota worsens the stress response.
Dysbiosis, permeability and inflammation: a vicious circle
In patients under chronic stress, the body’s response does not stay confined to the nervous system.
Under the effect of cortisol and pro-inflammatory cytokines, the intestinal lining weakens, promoting increased permeability4. This allows inflammatory compounds (such as LPS) to pass through, sustaining low-grade inflammation, worsening dysbiosis, and reinforcing the stress response.
This is a vicious circle: stress → inflammation → dysbiosis → worsening stress.
In consultation, this shows up as persistent fatigue, emotional instability, functional digestive disorders or resistance to conventional approaches.
This is why acting on the microbiota becomes a clinical priority, just as much as supporting the HPA axis.
3. Gut microbiota and stress: clinical recommendations
In chronically stressed patients, simply supporting the HPA axis is often not enough.
Restoring a functional microbiota, correcting stress-induced deficits, and rebalancing neuromediators are clinical priorities to prevent exhaustion or the condition becoming chronic.
Here are the main areas for intervention to draw on, according to the patient’s profile:
Clinical objectiveLevers to useConcrete actions to put in placeReduce vulnerability to stressDietary correction and magnesium support5A diet rich in magnesium (nuts and seeds, green vegetables, mineral water), reducing stimulants (coffee, sugar, phosphates)Calming the neuro-inflammatory responseOmega-3 + antioxidantsOily fish twice a week, rapeseed/flaxseed/camelina oil, colourful vegetables, turmeric, polyphenolsRebalancing neuromediatorsChrononutrition + precursor amino acidsAnimal protein in the morning (dopamine), complex carbohydrates + tryptophan later in the day (serotonin, melatonin)Restoring the microbiota-brain axisSpecific probiotics + prebiotics + permeability supportLactobacillus plantarum P128™, L. helveticus R0052, Bifidobacterium longum R0175, soluble fibre, glutamine, zincSupporting long-term adaptationAdaptogens and stress cofactorsStandardised ashwagandha (≥2.5% withanolides), microencapsulated saffron, bioactive L-theanine, standardised rhodiola
💡 Be wary of the “kitchen-sink list” effect: favour targeted courses of treatment tailored to the patient’s terrain, the stage of stress (acute, chronic, post-burnout) and the degree of adrenal exhaustion.
Conclusion: putting the microbiota back at the heart of care
Behind insomnia, cravings or chronic fatigue, a harmful intestinal terrain can sometimes be hiding, silent but active.
As a practitioner, acting on the microbiota-brain axis allows you to move beyond conventional approaches and restore genuine physiological resilience.
3 habits to keep in mind:
Think “microbiota” as soon as the HPA axis starts to exhaust, especially if the patient is not improving despite conventional approaches
Prioritise well-documented strains for stress regulation: L. plantarum, L. helveticus, B. longum
Also target permeability (glutamine, zinc, fibre): a leaky gut can sustain stress through silent inflammation
Would you like to bring these approaches into your practice, or find out more about the recommended products? Contact our team to discuss it further!
