Over time, the surface area of the small intestine becomes damaged, causing a flattening or atrophy of the microvilli (tiny hairs that help with the transportation of food through the intestine). This leads to malabsorption of all nutrients (vitamins, minerals, fats, proteins and carbohydrates) and, typically, weight loss, although many other conditions can ensue as well.
The reason this occurs is not wholly understood, but one theory is that there is a lack of appropriate digestive enzymes. Another theory is that the immune system perceives a part of the gluten protein to be ‘foreign’ and attacks it. In the ensuing battle, the immune system inadvertently damages the intestinal lining.
The symptoms include bloating, diarrhoea, foul-smelling stools, pale stools, and poor growth in babies and children. In adults there can also be pain, malaise, weakness and weight loss. Fatigue and irritability are also common. The skin and tongue may appear pale due to a lack of the normal red pigment found in blood. Bone problems may occur, such as deformity, pain or propensity to fracture.
Since nutrients are incompletely absorbed, increased bowel frequency, with the passage of bulky, pale stools, may occur; there may be associated abdominal pain and/or distension. However, many sufferers experience no bowel disturbance, and may be constipated rather than suffer diarrhoea.
It is likely that many people with gluten sensitivity have few or no symptoms, so the condition can remain unrecognized.
How Common Is It?
In Britain, the condition affects approximately 1 in 1,000 people. If one family member is affected it is more likely that others in the same family will have it as well. The frequency of gluten sensitivity is greater than among the general population in people with certain other disorders, particularly those with the type of diabetes that requires insulin.
Although not backed by solid research evidence, one estimate puts the figure at much higher than 1 in a 1,000, and more like 1 in 200. This is consistent with the suggestion that for every coeliac known there are five others who have yet to be identified. Perhaps with the wider recognition and acceptance of food intolerances, these individuals will either come forward or be identified by a practitioner, and we will have a better idea of how widespread this problem is.
How Is It Treated?
Treatment involves avoiding all gluten foods – namely wheat, rye, barley and oats. Once the intestinal lining has been damaged, however, it can take some time to repair itself, and usually the individual needs to replenish nutrients either intravenously or orally. In many cases there are a host of other foods to which the coeliac sufferer is intolerant (soy and milk, for instance) due to the damage done to the intestinal lining, which often means that even if they avoid gluten their health does not immediately return to normal.
What Complications Can Arise?
Women with untreated gluten sensitivity can experience infertility, though this reverses itself once glutens are withdrawn from the diet. Before and during pregnancy, women with gluten sensitivity should be particularly careful to take a supplement of folic acid, as advised for all women.
Thinning of bones (osteoporosis) may be more common among people with coeliac disease than in the general population.
Dermatitis herpetiformis
People with an itchy, blistering skin eruption affecting the knees, elbows, buttocks and back, called dermatitis herpetiformis, almost always also show evidence of gluten sensitivity on intestinal biopsy. Zinc deficiency may also be a significant nutritionally-related issue with this condition, for which zinc supplements are needed.
Coeliac Disease and Mental Health
Interestingly, many people with coeliac disease also suffer bipolar disorder, highlighting the connection not only between the intestines and the brain but between gluten intolerance and brain functioning. Symptoms associated with gluten intolerance (rather than coeliac disease) include altered behaviour, depression, irritability and a short attention span.
An Inherited Disposition
It would appear that coeliac disease is at least partly an inherited disposition, because it runs in families. It is a condition that does not have to be present at birth to later reveal itself. One belief is that coeliac disease is a manifestation of humans’ inability to adapt to wheat, which has only been available to humanity over the past 10,000 years – the blink of an eye in evolutionary terms. However, this does not explain the prevalence of wheat intolerance, the most likely cause of which is the sheer repetition and high doses that we consume, possibly at every meal and snack.
Coeliac Testing
Just because you experience symptoms after eating foods that contain gluten, this does not mean you have coeliac disease. The definitive test is a biopsy from the surface of the small intestine.
A flexible telescope (endoscope) is usually passed through the mouth into the stomach and upper intestine so that the lining can be inspected and a biopsy taken. This process takes only a few minutes and is often made easier and less uncomfortable by giving the patient a mild sedative beforehand. Alternatively, a biopsy can be obtained by swallowing a special capsule on the end of a narrow tube.
If the biopsy is abnormal, a second test may be advised after a period to check that the intestinal surface has returned to normal.
When there is doubt about an earlier diagnosis, or the changes seen on biopsy are uncertain, another biopsy may be advised after a person has deliberately eaten gluten for a period (this is called a ‘gluten challenge’).
Blood tests are helpful in detecting the body’s reaction (antibodies) to gluten or as an indication of intestinal damage. The blood test that can give a strong indication of coeliac disease analyses tissue transglutaminase IgA levels along with reticulin and endomysial IgA antibodies. A positive result in this test also gives an indication of an inherited susceptibility to gluten intolerance. Other blood tests can be used to identify deficiencies of iron, vitamins such as folic acid, or minerals such as calcium. Such blood tests are useful for screening relatives or to ascertain whether a gluten sensitivity may be the cause of symptoms or of nutrient deficiency. These tests do not make the diagnosis, but indicate the advisability of a biopsy test.
If abdominal symptoms are troublesome or develop despite treatment, a barium X-ray of the intestine, which involves swallowing a tasteless white liquid, may be advised.
For more information about coeliac disease, please contact:
Coeliac Society of the UK
PO Box 220
High Wycombe, Buckinghamshire
HP11 2HY
Tel: 01494 437 278
www.digestivedisorders.org.uk
