Saturday, March 30, 2013

The Many Faces of Coeliac Disease

Suffering from diarrhoea, abdominal pain and / or weight loss? These are some of the key symptoms that might alert a doctor to the possibility of coeliac disease or an issue with gluten. Research, however suggests that individuals suffering from these 'classic' symptoms are merely the tip of the iceberg and that there are many, many more people who are likely to be affected..

So how does Coeliac Disease differ from gluten intolerance?

Coeliac disease is an autoimmune disease where in genetically susceptible individuals the villi in the small intestine (where food is absorbed), are progressively destroyed causing nutrient malabsorption. In non - coeliac gluten intolerance this villi damage does not happen, although gluten intolerance has still been associated with many serious health issues as we shall see

So what health issues are caused by gluten?

In some individuals the presenting symptoms will be similar to those described above, however in the majority of cases, ( yes it is important to note that it is in fact the majority of cases!), symptoms will be different or in fact there may be no symptoms at all. If symptoms are present then these may include digestive issues such as constipation, indigestion, bloating and flatulence. Alternatively signs and symptoms seemingly unrelated to the gut might emerge such as headaches, depression, schizophrenia, skin problems such as psoriasis and eczema and other autoimmune conditions such as hashimotos thyroiditis, graves disease, MS, lupus, abnormal liver function tests, infertility, anaemia, B12 deficiency and tiredness.

But if I've been tested then I have no need to worry do I?

In the UK, the main way that Coeliac disease is screened for is initially by a blood test for anti transglutaminase antibodies. Sometimes anti endomysial antibodies are also included. If the blood results come back as normal, then the individual is generally considered to be coeliac free and no further testing is deemed necessary. Generally they are told that they can continue to eat gluten and the case is closed. The problem with this is that the blood tests are in fact very accurate, very accurate indeed - if and here's the big 'if' - you have total villous atrophy. Research indicates than in this scenario the tests are 90-95% accurate

However, the damage caused by coeliac disease doesn't happen overnight. You don't go to bed with perfectly healthy villi one day and wake up the next with them totally flattened. It takes time to happen and in some individuals it can take years and years. During this time you may or may not be experiencing any signs or symptoms related to gluten intolerance, but if you are susceptible then an inflammatory process is going on and sooner or later it will make itself known one way or another.

An additional problem with this test is that IgA anti tissue transglutaminase and anti endomysial antibodies are measured. This is fine provided the individual has adequate levels of IgA antibodies. However we know from research that IgA deficiency is more prevalent in coeliacs. This means that a negative result on a coeliac test may be caused by this IgA deficiency and may in fact be a false negative.

More false negatives may be found on tests from individuals who have suspected a gluten intolerance and have attempted to self medicate by avoiding wheat and other gluten containing grains.

So if the Coeliac tests aren't that accurate then how else can I find out if gluten is a problem for me?

Although there are no 100% fool proof tests for gluten sensitivity you can increase the reliability of the tests by requesting a total IgA test to see whether IgA deficiency is an issue for you. It is also worth getting tested for both anti tissue transglutaminase and anti endomysial antibodies (both IgA and IgG). Research shows that including both markers increases the accuracy of the test and helps with diagnosis. Genetic testing for coeliac disease is also available and if positive increases the likelihood of gluten being an issue for you.

If the Coeliac markers are still negative then it is worth having a blood test which measures levels of antibodies (IgG and IgA) to gliadin (the toxic element of gluten). Unlike the other antibodies, which are autoimmune antibodies, anti- gliadin antibodies are antibodies to the food itself. We produce them in much the same way as we produce antibodies to milk proteins, egg proteins or to other foods and it is possible that these may be produced before we start producing autoimmune antibodies. This test is also useful for detecting non celiac gluten intolerance.

The bottom line however is this: if you know that gluten disagrees with you or you have a history of gluten intolerance or coeliac disease in your family it would be sensible to strictly avoid gluten to prevent the likelihood of developing one of the many diseases associated with gluten sensitivity.

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