Advising patients to go onto a gluten free diet even a few years ago was always rather miserable: a lifetime of heavy bread and rubbery pasta, and often requiring a prescription. A stroll down the aisles of most supermarkets now, is testimony to the explosion of the Gluten Free trend. Palatable bread, sausages, ready meals, pesto, even foods that would never contain gluten are stamped 'naturally gluten free' to get in on the act. The reason for this is gluten has gone from being solely linked with coeliac disease (since this was established in 1952) and has now been accused of causing many illnesses from eczema to depression. There are also many high profile celebrity endorsements for going gluten free.
Gluten is made up of two proteins (gliadin and glutenin), which are brought together in the dough making process of mixing flour and water to give it structure and elasticity. Gluten is found in wheat, and also other grains like barley and rye. Gluten is therefore not just found in bread, pasta, cakes and biscuits but also stocks, sauces, and processed foods. Patients with coeliac disease must avoid gluten as their immune system reacts to gluten to lead to inflammation and damage to the lining of the bowel. This leads to abdominal pain, diarrhoea, weight loss, fatigue and also nutritional deficiencies. If coeliac is left untreated there is a greater risk of cancer and osteoporosis. Hence people with the symptoms that might mean coeliac disease should have a blood test looking for the antibodies implicated in the gluten allergy, which is a very reliable screening test. About 1% of people in the UK are thought to have coeliac disease.
So, if somebody does not have coeliac disease why might they feel better when they avoid gluten? This phenomenon has not been fully explained, but has found itself with the label of non-coeliac gluten sensitivity. We do know these people do not have coeliac disease, but is gluten definitely to blame? Yeasts and even pesticides have been implicated as the component of traditional gluten containing foods that might be triggering these symptoms. Also people with abdominal pain, diarrhoea and wind may respond to a low FODMAPs diet (fermentable oligo- di- and monosaccharides and polyols). FODMAPs are present in many fruit and vegetables, but also are in gluten containing grains. Maybe a gluten free diet works in these people because they are eating less of these fermentable FODMAPs.
Why has the incidence of coeliac disease risen? It has been claimed that the industrialization of bread making may have led to both strains of grain that have different proteins and also due to faster production processes, proteins we did not used to be exposed to now survive the baking process. Some bread manufacturers even add extra gluten to bread to make it springier. Hence, the link between coeliac disease and gluten is indisputable. However, the notion of other health benefits of going gluten free needs more evidence and scrutiny, although it is likely to help some patients with functional abdominal symptoms of irritable bowel syndrome.