You know that feeling of brain fog? Like there's cotton wool in your head, your concentration disappears and your energy sinks. Many people look for the cause in sleep deprivation or stress, but more and more research is pointing to a surprising source: your gut. Through the gut-brain axis, your microbiome and brain are in constant communication.

What is the gut-brain axis?

The gut-brain axis is the two-way connection between your gut and brain. This communication is through:

• Nerve pathways (such as the vagus nerve, a kind of highway between the abdomen and brain).
• Hormones and neurotransmitters (e.g., serotonin, 90% of which is produced in the gut).
• Immune signals and inflammatory factors.

Nature Reviews Neuroscience (2022) emphasizes that the gut is a "second brain" that constantly exchanges messages with our central nervous system.

How your microbiome affects your brain

• Neurotransmitters: bacteria such as Lactobacillus and Bifidobacterium make substances that affect the production of serotonin and dopamine.
• Inflammation inhibition: a healthy microbiome produces short-chain fatty acids (SCFAs) that dampen inflammatory processes - crucial, as low-grade inflammation is linked to depression and brain fog(The Lancet Psychiatry, 2021).
• Stress regulation: a diverse microbiome helps better balance cortisol levels(Harvard Health, 2022).

Brain fog: a signal from your gut

Brain fog is often not an isolated problem, but a symptom of crosstalk dysbalance between gut and brain. Possible causes include:

• Food intolerances → lactose or histamine can trigger inflammation in the intestines and brain fog.
• Microbiome depletion → fewer SCFAs = less fuel for brain cells.
• Stress → increases permeability of the intestinal wall ("leaky gut"), which in turn affects concentration and energy.

Oxford research (2021) shows that interventions that improve the microbiome (diet, probiotics, lifestyle) significantly enhance cognitive performance.

What to do about brain fog?

Not everyone responds well to standard advice like "eat more fiber." In some people, this actually causes additional symptoms due to limited fiber digestion. Fortunately, there are more innovative ways to support the gut-brain axis:

1. Targeted polyphenols
   - Pure cocoa, blueberries or green tea feed bacteria that stimulate neurotransmitters and antioxidants(Nature Metabolism, 2021).
2. Tryptophan rhythm hack
   - Foods rich in tryptophan (e.g. pumpkin seeds, turkey, sesame seeds) in the evening can improve serotonin and melatonin balance.
3. Cyclic prebiotic shifts
   - Instead of always lots of fiber: cyclic intake of fermentable nutrients (e.g. resistant starch from green banana flour or cooled potatoes). This prevents overload in sensitive intestines.
4. Postbiotics
   - Substances such as butyrate or propionate (SCFAs in ready-to-use form) mimic the benefits of a healthy microbiome, even with poor fiber digestion.
5. Vagus nerve training
   - Through deep breathing, cold stimuli or chanting/neurling, you directly stimulate the vagus nerve, thus better balancing the gut-brain axis(Frontiers in Neuroscience, 2020).
6. Circadian nutrition
   - Not what but when: your microbiome follows a day-night rhythm. Meal clustering within 10-12 hours synchronizes the gut-brain axis and reduces brain fog.

My InnerSelfie and the gut-brain axis

With a My InnerSelfie test, you map your gut microbiome, DNA and metabolites together. This not only gives you insight into your physical health, but also into your cognitive clarity and mental resilience.

Brain fog thus becomes not a mystery, but a signal you can measure and improve.

Key insights

• The gut-brain axis is a bidirectional connection between gut and brain.
• Your microbiome influences neurotransmitters, inflammation and stress.
• Brain fog can arise from imbalance in the gut-brain axis.
• There are more biohacks than just fiber, sleep and exercise.
• Multi-omics testing makes these signals visible and controllable.

Scientific references

• Nature Reviews Neuroscience. (2022). Gut-brain communication and health.
• The Lancet Psychiatry. (2021). Inflammation, microbiome and mental health.
• Harvard Health. (2022). Stress, gut health and brain function.
• Oxford University Press. (2021). Gut microbiota modulation and cognition.
• Nature Metabolism. (2021). Polyphenols and microbiota-driven brain health.
• Frontiers in Neuroscience. (2020). Vagus nerve stimulation and cognitive function.