The cause of coeliac disease is almost certainly the loss of certain strains of commensal bacteria – for example strains of lactobacillus, Bifidobacterium, Firmicutes and Bacteroidetes. It is not gluten.
Symptoms of Celiac Disease
Typical symptoms include gastrointestinal problems such as repeated diarrhoea, swollen abdomen, absorption problems and loss of appetite.
In small children this can interfere with normal growth.
Out of date definition of Celiac or coeliac disease
The disease is often called an immune disease or an autoimmune disorder. It is associated with other so called autoimmune diseases such as Hashimoto’s thyroiditis. The term ‘autoimmune disease’ was originally used for disease where inflammation was common and the immune system over-reacted – an inexplicable problem associated with the patient. Now we know coeliac disease is an easily explained problem which develops from a loss of important gut bacteria (like Hashimoto’s, which is associated with SIBO – small intestine bacterial overgrowth)
Go to: Hashimoto’s disease
The laziness associated with the term autoimmune disease has left people confused. For example, it is often reported that the disease is ‘caused’ by gluten. This is simply not true.
The cause of Coeliac Disease
People with the condition may well have a reaction to gluten, a protein typically found in wheat, rye and barley. This can prompt inflammation and in some cases – but not always – the production of antibodies, as if some foreign body were present. Antibody tests are not always positive.
Patients may have a shortening of the villi that line the intestine; gluten also turns on an enzyme (zonulin) known to increase permeability and even create openings in the gut lining for yeasts to cross into the blood stream. But this can happen even if you do not have coeliac disease.
And a gluten-free diet, while it helps, is not the answer. A study in the Journal of Gastroenterology showed that even on a gluten free diet patients still exhibited a much higher rate of gastrointestinal problems than a healthy individual (1).
The bacterial cause of coeliac disease
The first evidence that this was a problem caused by the microbiome appeared in a 2014 Finnish study in the same journal (2). Even in totally gluten-free patients, symptoms persisted, and researchers showed that this was due to a completely different microbiota profile to that of a healthy individual. Those with coeliac disease had higher levels of Proteobacteria but lower levels of Firmicutes and Bacteroidetes (the latter being known to influence intestinal lining formation). Overall the diversity of the microbiome was far lower. People with coeliac disease have lost significant numbers of different strains of ‘good’ (commensal) gut bacteria. Even those on a strict gluten-free diet!
About the same time, a study appeared in the journal Inflammatory Bowel Disease showing that the microbiome differed between different people with coeliac disease so that symptoms differed (3). One patient might get severe stomach cramps, another migraine.
The risk can start young. Infants that went on to develop CD had lower levels of Bifidobacterium longum and higher levels of Enterococcus long before they developed CD Symptoms (4). This is a 2018 study in the journal Microbiome.
A recent meta-analysis by researchers at the Farncombe Family Digestive Health Institute at McMaster University in Canada has shown that coeliac disease is linked to IBD and vice versa. Having coeliac disease gives you a nine-fold higher risk of developing Intestinal Bowel Disease (5).
Having IBS also gives you a higher risk of developing CD. IBS, or IBD, is understood to be caused by an imbalance of the gut microbiome.
Tryptophan and coeliac disease
Then the same researchers found that a diet high in tryptophan may help. Tryptophan is an essential amino acid (meaning that you cannot make it yourself, you have to consume it).
Tryptophan is needed for growth and development, niacin (vitamin B3) and serotonin production, the last being linked to mood and sleep changes.
Tryptophan is found in chicken, turkey, pork, red meat, fish, tofu, beans, greens (like broccoli and cabbage), nuts, seeds and eggs.
Tryptophan is broken down by certain gut bacteria into chemicals that stimulate receptors in the gut lining and reduce inflammation. One of these receptors is the Aryl Hydrocarbon Receptor or AhR, known to be poorly activated in chronic inflammatory diseases of the gut such as IBS, colitis and Crohn’s. This is true for coeliacs too.
Poor AhR stimulation lowers anti-inflammatory molecules in the gut wall and damages the gut barrier. Two Lactobacillus strains were found to be part of the normal breakdown of tryptophan; if they are missing then poor AhR stimulation is the result (6).
Bifidobacterium and Lactobacillus strains are now understood to be Lactic Acid bacteria, found in very high levels in babies, damaged by antibiotics, vaccines, drugs, smoking, alcohol, stress and parasites, for example.
Go to: Lactic Acid bacteria