By Matt O'Neill, MSc(Nut&Diet), APD
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There's a lot of marketing and buzz going around about the evils of gluten in our diet and the increased prevalence of coeliac disease. But do you need to be concerned about gluten - wheat protein - and eliminate it from your diet? In this article, I explain all.
What is gluten and coeliac disease?
The Neolithic Revolution, which occurred around 10,000 years ago was when animals were first domesticated and crops were cultivated. This introduced a whole range of new foods and proteins into the human digestive system.
While most proteins were readily consumed, some people's immune systems struggled to tolerate others. As an agricultural crop the widespread consumption of wheat triggered, in a portion of the population, gluten intolerance or coeliac disease.
When people with coeliac disease consume gluten, an abnormal immune reaction occurs involving T cells, which results in inflammation and damage to the small bowel lining. This impairs absorption of nutrients and can lead to a wide range of symptoms and medical complications.
Prevalence and the reasons why
Today, coeliac disease affects more than 1 in 100 Australians. Over the last half century, it has become approximately twice as common every two decades.
Why the prevalence is increasing remains unknown, but a variety of environmental factors and the `hygiene hypotheseis' (too much cleanliness) have been proposed.
People are typically diagnosed in adulthood and are mostly female. Alarmingly, 80% of Australians with coeliac disease remain undiagnosed. This is because symptoms are wide-ranging and largely non-specific.
Symptoms and diagnosis
In people with coeliac disease, gluten causes widespread inflammation not limited to the bowel. Sufferers are commonly troubled by gut upset (such as abdominal pain, bloating, diarrhoea and/or constipation), lethargy and nutrient deficiencies, such as low iron. They can also suffer loss of fertility, migraine headaches, abnormal liver function, arthritis and autoimmune diseases, such as type 1 diabetes.
Bones are more likely to be thinned out (osteoporosis) and sufferers can develop certain cancers, such as lymphoma. The good news is that early diagnosis and treatment can greatly reduce the chances of these complications.
A blood test is used to screen for coeliac disease. However, a bowel sample is required to make a definite diagnosis, where flattening and inflammation of the small bowel lining is found under the microscope.
Small bowel samples are obtained by gastroscopy, a ten-minute procedure performed under sedation that introduces a flexible instrument via the mouth into the small bowel.
It's vital that a gluten-free diet isn't started before testing for coeliac disease, as this can cause false negative results.
Genes and the environment
Coeliac disease shares certain predisposing genes with autoimmune diseases, such as type 1 diabetes. These genes control how the immune system `recognises' and responds to foreign proteins and are fundamental for the disease to develop.
Genes alone are not enough to cause coeliac disease and environmental factors are thought to play an important role in `triggering' disease in those with genetic susceptibility. Some factors appear to increase coeliac disease risk, such as rotavirus infection in infancy, while some may reduce the risk. Breastfeeding at the time gluten is introduced to an infant, for instance, may protect against developing the disease.
Excluding all dietary sources of gluten from wheat, rye, barley and oats allows the small bowel damage to heal and symptoms to resolve, but it's not easy. Wheat flour, the most common and significant source of gluten, is found in many foods such as bread, breakfast cereals, cakes, biscuits and pastries.
There are also `hidden' sources of gluten found in sauces and processed foods and less obvious items, such as malted foods and beer. Gluten-free alternatives are increasingly available, however, but may be less palatable and require adjustment of taste buds.
The gluten-free diet needs to be very strict to work. Even small amounts of gluten (about 50mg which is less than 1/100th of a slice of bread), can cause bowel damage.
Is gluten-free for everyone?
A recent market survey commissioned by Coeliac Australia indicates that approximately 10% of Australians are currently following a strict or significantly reduced gluten diet.
This is ten times greater than the total number of Australians thought to have coeliac disease and is most likely due to the mounting public perception that a gluten-free diet is `healthy' or suitable to treat a variety of symptoms and illnesses.
While many people feel their symptoms might improve on a gluten-free diet, this doesn't necessarily mean they have coeliac disease. Nor does it mean a gluten-free diet is the most appropriate treatment for them.
Many cases of perceived wheat or gluten intolerance reported by patients is not due to gluten itself but intolerance to the wheat's carbohydrate component (fructans). For some, a diet reducing fructans and other fermentable carbohydrates, a low FODMAP diet can be a more effective and appropriate treatment than going gluten-free.
So, you can understand that gluten intolerance, like any other food intolerance or allergy can be quite tricky. If you feel you may be experiencing symptoms of coeliac disease or any digestive distress, please see your Doctor and ask to for advice and testing, if required.
Then, I'd recommend seeing an Accredited Practising Dietitian (APD) who specialises in food allergies and intolerances for further dietary assessment, advice and ideally a list of foods to avoid and include in your diet.
It's worth the effort to get checked out properly rather and get expert help to build a dietary plan to feel better.
Bottom line - You don't need to be afraid of gluten. But if you can't tolerate gluten, you need to avoid it and get onto a gluten-free nutrient-rich diet.
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