Coeliac Disease
Coeliac Disease
During World War 11, there was no bread to be had in the Netherlands and people were forced to eat tulip bulbs. ‘My mother roasted them,’ one survivor recalls, ‘and they tasted delicious then, because we were so hungry I suppose. I cooked some years later, just to taste them again, and they were absolutely disgusting.’
While most of the population was thin and unwell on this starvation diet, a few children were actually healthier than before. An observant Dutch doctor noted that these were the children who, before the war, had suffered from constant diarrhoea, fatigue, poor growth and muscle wasting. They were suddenly stronger and, his enquiries revealed, their diarrhoea had vanished. But when the food situation improved at the end of the war, all their old problems returned. By carefully experimenting with the diet of these patients, the doctor discovered that eating wheat and rye caused the symptoms. Subsequent research has revealed that both contain a collection of proteins, referred to as gluten, which are the source of coeliac disease.
Belly disease
Coeliac disease (or celiac disease) is an old name which simply means ‘belly disease’. It is derived from the Greek word for’belly’ — koilia. Once the cause of the symptoms became understood, a new name was devised — gluten-sensitivity enteropathy — but it has not really caught on. Other terms that you may come across are non-tropical sprue and coeliac sprue, based on the close resemblance of the symptoms to those of tropical sprue. This disease, found in those who live or have lived in the tropics, is probably caused by bacterial infection. There is no causal link with coeliac disease.
Symptoms
The symptoms of coeliac disease are:
• diarrhoea, with pale, bad-smelling stools
• in a few patients, constipation rather than diarrhoea, but this is very rare
• bloating and wind
• damage to the lining of the intestine. This is of a characteristic type: the complex folded structures (the villi) of the intestinal lining are destroyed. Additionally, huge numbers of immune cells are present.
• the loss of the villi results in failure to absorb nutrients from food (malabsorption) causing poor growth in babies, and weakness and weight-loss in adults.
• poor appetite, especially in babies. This can greatly reduce the diarrhoea.
Coeliac disease usually appears in babies during weaning, a few weeks after cereals are introduced, but it can also begin for the first time in adults. The tendency to coeliac disease is genetically inherited, so it runs in families.
Where coeliac disease runs in the family, another disease, dermatitis herpetiformis, is also likely to occur. Dermatitis herpetiformis has the same basic mechanism as coeliac disease but very different symptoms:
• an intensely itchy rash, sometimes with tiny blisters; the rash is symmetrically distributed on the buttocks, shoulders, scalp, and the outer surfaces of the knees and elbows
• the same characteristic damage to the lining of the intestine as seen in tests for coeliac disease, though generally less severe
• diarrhoea, in some cases, but not all. About 5% of those with coeliac disease actually go on to develop dermatitis herpetiformis. Most people have either one or the other.
Both diseases are caused by the same gene, which results in sufferers developing antibodies against one of their own proteins, an enzyme called tissue-transglutaminase. The job of this enzyme, which is found in the intestines, is to assist with the breakdown of gluten.
If no gluten is present, the enzyme does not arouse the interest of the immune system. It is the process of gluten digestion, in which a particular peptide is produced from gluten, that provokes the autoimmune reaction. (A peptide is any short length of protein chain, obtained from the complete protein chain by digestion.)
What seems to trigger the autoimmune reaction is this enzyme–peptide combination: the offending peptide, newly produced and still attached physically to the enzyme. There is something about the particular ‘chemical picture’ that this combination makes which outrages the immune system of individuals with a particular genetic make-up.
The impact of this autoimmune reaction on the intestinal lining is severe in coeliac disease, less so in dermatitis herpetiformis. What causes dermatitis herpetiformis is a particular type of antibody, called dimeric IgA, which is transported by the bloodstream from the gut to the skin. It is deposited in the skin all over the body, but for some reason only provokes inflammation in certain areas.
In rare cases, an IgE-mediated food allergy to wheat can co-exist with coeliac disease, making reactions more severe.
Secondary problems
Paradoxically, while the damaged gut lining of untreated coeliac disease makes a poor job of absorbing specific nutrients (e.g. iron and vitamins) in a form that the body can use, it also lets through far more intact, or partially digested, food molecules. These get into the bloodstream in such numbers that they can lead to idiopathic food intolerance (see p.74). Sensitivity to soya is a common problem, because it is so heavily used in gluten-free bread and other prepared food. Those with coeliac disease who have not improved fully, despite a strict gluten-free diet, often benefit from an elimination diet (see p. 194). This must be done under medical supervision.
Another possible effect of the intestinal damage is lactose intolerance (see p.79), producing a sensitivity to milk.
The frequency of schizophrenia is higher among those with coeliac disease than among the general population. Coeliacs not following a strict gluten-free diet are also vulnerable to other psychological problems. These might be linked to the effects of food-derived exorphins (see pp. 76-7) and other peptides on the brain. The increased permeability of the gut could play a part in this, allowing more exorphins to reach the bloodstream.
Diagnosis
A biopsy (see p. 92) is the only really reliable form of diagnosis. It is crucial that this is done before removing gluten from the diet, because the damage is repaired if gluten is avoided and the healing process is fairly rapid for some people (though in others it takes many months). If the intestinal lining reverts to a normal appearance quite quickly, an accurate diagnosis is never obtained, which can have serious consequences: if you or your child are coeliac, you need to know.
New blood tests can also be helpful in diagnosis, but they do not give the unequivocal result obtained with a biopsy.
Research from the United States suggests that coeliac disease is under-diagnosed in some countries compared to others – for example, Italy screens children routinely but the States does not. Some authorities suspect that there is a great deal of ‘hidden’ coeliac disease in the States, and this could be true in other countries as well. There is no routine screening of children in Britain.
The symptoms of coeliac disease are not always distinctive. Many cases are first detected when patients with rather non-specific symptoms are discovered, by a blood test, to be anaemic.
Treatment
There are no drug treatments for coeliac disease and avoiding gluten religiously is the only way to remain well. Those who are lax about their gluten-free diet may be more vulnerable to certain cancers of the digestive tract.
A strict gluten-free diet is not easy to follow (see p. 177). The most severely affected coeliacs are so sensitive to gluten that they react violently to even a tiny amount: this is known as coeliac shock and can be fatal.
A gluten-free diet is also the treatment for dermatitis herpetiformis, but at the outset the rash can be controlled with the highly effective drug dapsone.