Gut profile microbiome & gut barrier – leaky gut test (stool)

Zonulin is a protein that can loosen the connections between the cells of the intestinal lining (tight junctions). When more zonulin is present, the gut wall can become more permeable (PubMed 21248165). That is why zonulin in stool is measured as a marker of the gut barrier and of "leaky gut".

Important for interpretation: a 2018 study showed that a widely used commercial zonulin assay does not detect zonulin itself but related proteins such as properdin (PubMed 29459849). The value is therefore an indication, not proof of a permeable gut wall, and is considered together with sIgA, histamine and the gut flora.

Secretory IgA is the most important antibody of the mucous membranes. The intestinal lining releases it into the gut, where it binds pathogens and foreign substances before they reach the lining (PubMed 21975936).

An elevated value can indicate an activated mucosal defence, for example with irritation or inflammation; a low value a weaker defence at the mucosa. Laboratories do not assess it uniformly; the report states the reference range of the laboratory that carried out the analysis.

Histamine is formed in the gut, among other things, when bacteria convert the amino acid histidine, and it occurs in foods such as aged cheese, wine or sauerkraut. It is broken down mainly by the enzyme diamine oxidase (DAO) in the intestinal lining (PubMed 33921522).

An elevated value in stool shows that there is a lot of histamine in the gut. Whether this contributes to complaints depends, among other things, on its breakdown; for the question of histamine intolerance there is the histamine and DAO analysis.

Yeasts such as Candida albicans are part of the normal gut flora in small amounts in many healthy people (PubMed 36135388). The report shows whether and in what amount Candida species are detectable.

Larger amounts can occur, for example, after antibiotics or with weakened immunity. Research is investigating the role of Candida in chronic inflammatory bowel diseases (PubMed 39735273). A distinct "Candida syndrome" with general complaints is not scientifically established.

Akkermansia muciniphila lives in the mucus layer of the gut wall and is associated with the gut barrier and metabolism; lower amounts have more often been found in overweight and metabolic disorders (PubMed 39940420). Bifidobacterium and Lactobacillus are lactic acid bacteria that contribute to an acidic gut environment. In studies of irritable bowel syndrome, Bifidobacterium was reduced (PubMed 30940523).

In addition there are E. coli and enterococci, which belong to the normal gut flora in small amounts. The report shows the amounts compared with the laboratory's reference range.

The digestion markers indicate how well the pancreas produces digestive enzymes, how bile acid metabolism is working and how well fat is broken down.

If the pancreas produces too few digestive enzymes (exocrine pancreatic insufficiency), this can show up as fatty stools, bloating, abdominal pain, diarrhoea and unintended weight loss (PubMed 37737818). Such complaints should be checked by a doctor; a home test does not replace that.

Stool pH reflects the environment in the large intestine. When gut bacteria ferment dietary fibre, short-chain fatty acids such as butyrate are produced and the pH falls (PubMed 11427691).

A rather high (alkaline) value can indicate that little fermentation is taking place, for example with a low-fibre diet; a very low (acidic) value can indicate strong fermentation, for example when carbohydrates such as lactose are not fully absorbed in the small intestine. pH alone does not allow a diagnosis.

The intestinal lining is a barrier: it lets nutrients through and holds back bacteria, toxins and undigested food components. It is held together, among other things, by tight junctions between the cells. "Leaky gut" describes a gut wall that is more permeable than usual (PubMed 31076401).

The term is colloquial. Increased permeability is well documented in various diseases; a distinct "leaky gut syndrome" as a diagnosis, however, is not established.

A review lists documented influences including endurance exercise, painkillers from the NSAID group (for example ibuprofen), pregnancy and certain food additives such as emulsifiers. Inflammatory and ulcerating bowel diseases are accompanied by increased permeability (PubMed 31076401).

Psychological stress is also being studied as an influence on the gut barrier (PubMed 36806451).

In research, gut permeability is measured mainly with sugar tests: you drink certain sugars and measure how much of them arrives in the urine (PubMed 31076401). In practice there are markers such as zonulin, measured in stool or blood.

This gut profile measures zonulin in stool together with sIgA, histamine, digestion markers and the gut flora. It therefore shows several indications of the state of the intestinal lining but cannot prove a permeable gut wall.

No. Increased permeability of the gut wall is well described in conditions such as coeliac disease or chronic inflammatory bowel diseases. A distinct "leaky gut syndrome", however, is not part of medical guidelines. Whether restoring the gut barrier improves complaints has not yet been shown (PubMed 31076401).

Research associates increased permeability of the gut wall with the following complaints and conditions, with varying strength of evidence:

• Irritable bowel syndrome with abdominal pain, bloating, distension, diarrhoea or constipation: increased permeability in some patients (PubMed 28404070).
• Coeliac disease and chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis: well documented (PubMed 31076401, PubMed 21248165).
• Autoimmune diseases: a link with zonulin is being researched, for example in type 1 diabetes (PubMed 32162764).
• Skin problems such as acne or atopic dermatitis: described in reviews via the "gut-skin axis" (PubMed 40050613).
• Stress, exhaustion and psychological strain: links between stress and the gut barrier are being studied (PubMed 36806451).

These are associations from studies, not causes in an individual. A stool test cannot explain complaints and does not provide a diagnosis. Persistent complaints should first be checked by a doctor.

Histamine intolerance is described with very different complaints that often occur after histamine-rich meals: bloating, abdominal pain and diarrhoea, headache, flushing, itching and hives, a runny or blocked nose and palpitations (PubMed 17490952).

These complaints are non-specific and can have many other causes, such as allergies. The diagnosis of histamine intolerance belongs with a doctor.

With blood in the stool or black stool, unintended weight loss, fever, diarrhoea at night, severe or new abdominal pain, persistent vomiting or difficulty swallowing, the first step is a doctor's practice, not a self-test. The same applies if your bowel habits change for the first time from around age 50 or if bowel cancer or chronic inflammatory bowel disease runs in the family.

If you suspect coeliac disease, do not stop eating gluten before the medical work-up, because the tests may otherwise come back falsely normal. A stool test does not replace bowel cancer screening.

This page does not give treatment recommendations. Whether a result means anything at all and which steps make sense depends on your overall situation: complaints, previous findings, medication and diet. That complaints improve by restoring the gut barrier has not yet been shown (PubMed 31076401).

What makes sense for you belongs in a conversation with the ORY expert team or with your doctor or naturopath, for example from the ORY expert network. The results consultation is included in the price.

No antibiotics for at least 4 weeks beforehand and no probiotic supplements for 1–2 weeks beforehand, so the sample reflects your usual gut flora. Only pause prescribed medication after talking to your doctor. The sample must not come into contact with toilet water, as this distorts zonulin, sIgA and histamine in particular; a collection aid is included. Send the sample only from Monday to Thursday.

Analysis usually takes 7–21 days from the arrival of the sample at the laboratory. As soon as your report is ready, we let you know. A results consultation with the ORY expert team is included in the price.

The gut profile microbiome & gut barrier costs €315 including VAT, shipping, return postage and results consultation.

Statutory health insurance in Germany generally does not cover stool analyses you order yourself. With private insurance, reimbursement may be possible; how it works is described under "Reimbursement by private insurance".

The gut profile microbiome & gut barrier (€315) combines selected key bacteria with zonulin, sIgA, histamine, digestion markers and pH. The basic gut profile (€285) is more compact. Microbiome Maxi Plus (€285) analyses the gut flora by molecular genetics with more than 400 bacterial species, but without mucosal markers; Microbiome Maxi Plus + gut barrier + absorption (€465) combines both. For histamine alone there is the histamine and DAO analysis.

Which scope makes sense for you can be clarified in the free initial consultation.