Can stress really make your gut sick?
Stress really can make your gut sick: from abdominal pain and altered bowel habits to an increased risk of IBS and stomach complaints. If you suffer from chronic gut symptoms, stress is a factor worth discussing with your doctor.
Stress disrupts the functioning of your gut in several ways at once. The movement of the intestinal wall becomes dysregulated: sometimes the gut works too fast (diarrhoea), sometimes too slowly (constipation). At the same time, sensitivity to pain from the abdominal organs increases, meaning that the same stimulus hits harder in someone under stress than it normally would.
The intestinal wall itself also becomes more vulnerable. Stress makes the gut wall more permeable, allowing particles that would not normally pass through it to do so. This is sometimes called 'leaky gut'. Whether that in itself causes disease has not yet been proven, and there is currently no good evidence that treatments aimed at improving that permeability actually reduce symptoms.
In irritable bowel syndrome (IBS, a condition involving chronic abdominal pain and altered bowel habits), the link with stress is fairly strong. Stress appears to influence both the onset and the worsening of IBS. In chronic inflammatory bowel diseases such as Crohn's disease or ulcerative colitis, the connection with stress is less certain: there is an association, but whether stress actually causes those diseases has not been demonstrated. For stomach ulcers and acid reflux, a probable link with stress also exists.
Stress also has a negative effect on the composition of gut bacteria, but how exactly that works remains largely unknown. Probiotics are being investigated as a possible way to relieve stress-related gut complaints, but the evidence for this is still too thin to base any concrete recommendations on.
Based on multiple review studies (PMID 22314561, 28176047, 31076401, 20664075). The evidence for most associations is moderately strong and probably causal, except for IBD (associational and limited) and for the clinical relevance of leaky gut treatments (insufficient evidence).
What does too little sleep do to your gut?
Sleep deprivation may disrupt your gut microbiome, but we do not yet know with certainty how large that effect is in humans. Getting good sleep is sensible regardless, for your metabolism and immune system; whether targeted gut intervention produces any benefit in cases of sleep deprivation has not yet been proven.
Can a disrupted gut microbiome weaken your immune system?
A disrupted gut microbiome demonstrably dysregulates your immune system and increases the risk of chronic inflammation. Eating fermented foods is the best-supported way to do something about it.
Are abdominal pain and bloating signs of an unhealthy gut?
Abdominal pain and bloating are a sign that your gut needs attention, but on their own they say little about how "unhealthy" that gut is. If you have prolonged or severe complaints, first have other causes ruled out and seek guidance on diet or treatment.
Can an unhealthy gut contribute to skin problems such as acne or eczema?
A disrupted gut microbiome is associated with acne and eczema, although that association has not yet been proven to be cause and effect. Eating more fibre and plant-based foods is a sensible first step; for targeted probiotics the evidence is still too mixed for a clear recommendation.
Is there a real connection between your gut microbiome and your mood or brain?
There is a biologically plausible and, in animal research, robustly supported connection between your gut microbiome and your brain, but causality has not yet been proven in healthy humans. A varied, fibre-rich diet is the most concrete step you can take right now.
Can your gut microbiome influence your risk of heart disease?
Your gut microbiome influences your heart health through metabolic by-products that can promote arterial hardening, high blood pressure and blood clots. The association is plausible, but how best to modify the gut microbiome to protect your heart has not yet been sufficiently proven: always discuss major interventions with your doctor.