Before you jump on the gluten free bandwagon, a review has found that only a small proportion of Australians who claim to feel rubbish after eating gluten are likely to be truly sensitive to gluten or wheat.
The review highlights a recent study which found that only 16 per cent of people who self-reported a gluten sensitivity actually have reproducible symptoms when they didn't know if they were being given wheat or a placebo.
The researchers say identifying people who are truly sensitive to gluten or wheat is important given that a gluten free diet has several drawbacks, including cost and nutrient content.
A double-blind, placebo-controlled, dietary crossover challenge with gluten is needed to confirm legitimate sensitivities.
From the study:
Non-coeliac gluten or wheat sensitivity results in gastrointestinal and/or extra-intestinal symptoms associated with the ingestion of gluten- or wheat-containing foods, in the absence of coeliac disease or wheat allergy.
Up to one in 100 people in Australia may have coeliac disease but many more report symptoms after eating wheat products.
A wide range of symptoms are associated with NCG/WS, including gastrointestinal, neurological, psychiatric, rheumatological and dermatological complaints.
The pathogenesis of NCG/WS is not well understood, but the innate immune system has been implicated, and there is overlap with coeliac disease and the functional gastrointestinal disorders (irritable bowel syndrome and functional dyspepsia).
If you think you have a problem with gluten - go see your doctor.
Update: Wondering exactly how a gluten-free diet is risky, nutrition-wise? Here's what the study authors had to say:
Gluten-free products are not necessarily equivalent to their gluten-containing counterparts regarding their macronutrient and micronutrient content. Several studies have demonstrated that gluten-free diets may not provide adequate amounts of trace elements and vitamins such as calcium, vitamin D, folate, thiamine, riboflavin and niacin. This translates to clinical studies which have demonstrated high rates of micronutrient deficiencies, such as folate and vitamin B in patients treated with a gluten-free diet.
The diet also differs in regards to protein and fat content, although accounts vary in regards to the specific breakdown.
A gluten-free diet may adversely affect cardiovascular risk factors such as total cholesterol levels, weight gain leading to obesity, glucose tolerance and blood pressure and may lead to development of the metabolic syndrome. A potential explanation for this is the higher glycaemic load of gluten-free foods. Again, accounts vary, with other studies demonstrating a potentially beneficial effect of a gluten-free diet on cardiovascular risk factors, for instance by increasing serum high-density lipoprotein levels.
A gluten-free diet may lead to exposure to toxins, with recent reports of high levels of arsenic being found in the urine of patients who self-reported adherence to a gluten-free diet. This may be due to the high arsenic content of rice and rice flour, often a substitute for wheat in gluten-free products.
Many of these observations are limited to studies in patients with coeliac disease who are on a gluten-free diet, and there is less in the literature regarding the health effects of a gluten-free diet in patients with NCG/WS. A gluten-free diet has also been shown to influence the intestinal microbiome, with a reduction in Veillonellaceae, a pro-inflammatory bacterial genus, after treatment with a gluten-free diet.