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Adopting a gluten-free diet is one of the most popular lifestyle trends in Australia, with an estimated one in 10 adults limiting their consumption of wheat-based products.
Along with a popular perception that cutting out gluten – the protein component of wheat, rye and barley – aids weight loss, many people shun bread, pasta and beer because they believe it improves gut health and alleviates symptoms like bloating, stomach pain and fatigue.
The thing is, gluten isn’t the culprit for most people. A growing body of evidence points the finger at a group of carbohydrates, or sugars, called FODMAPs – which stands for ‘fermentable oligosaccharides, disaccharides, monosaccharides and polyols’ – that aren’t properly absorbed by the digestive system.
‘Coeliac disease affects a small percentage of the population, but for the majority of people who experience gastrointestinal symptoms following the consumption of wheat-based foods it’s likely that FODMAPS may be the issue,’ says Dr Rhiannon Snipe from the School of Exercise and Nutrition Sciences at Deakin University.
FODMAPs are found naturally in many foods and food additives. They are the lactose in milk and cheese, the fructose in honey and apples, and, crucially, the fructans in wheat, rye and barley.
FODMAPs are fermented by the bacteria living in your intestines. Most people ingest FODMAPs without any problems, but people with gut conditions like irritable bowel syndrome (IBS) – which affects a whopping one in seven adults – can experience gastrointestinal discomfort like lower abdominal pain, bloating, wind and altered bowel habits.
A strict gluten-free diet for life is the only treatment for coeliac disease, a permanent autoimmune disorder that causes gut issues like bloating, abdominal pain, diarrhoea, lethargy and anaemia. It’s also associated with infertility, migraine headaches, abnormal liver function, arthritis, osteoporosis and autoimmune diseases such as type 1 diabetes and thyroid disease.
Coeliac disease is relatively rare and affects one in 70 Australians. For everyone else who isn’t affected by the condition, there’s not a lot of evidence that eating gluten is harmful. In fact, a gluten-free diet can be distinctly unhealthy. To compensate for the missing taste and texture of gluten, many gluten-free foods are packed with fat and sugar.
'For the majority of people who experience gastrointestinal symptoms following the consumption of wheat-based foods it’s likely that FODMAPS may be the issue.'
Dr Rhiannon Snipe,
School of Exercise and Nutrition Sciences, Deakin University
Some people go gluten-free and notice an improvement in gut symptoms but an emerging body of research shows that a low-FODMAP diet, which reduces foods containing the carbohydrates, can be more effective in reducing symptoms than going gluten-free.
Confusion abounds because foods high in gluten are often high in FODMAPs, explains Dr Snipe.
‘A lot of the wheat, barley and rye products that contain gluten also contain FODMAPs,’ she says. ‘A series of large double-blind randomised crossover studies have given people gluten and FODMAPs and examined their symptoms, and it was the FODMAP components in wheat, barley and rye that were causing more symptoms than the gluten.’
Dr Snipe says about 70% to 80% of people with IBS experience symptomatic relief when they follow a low-FODMAP diet, which is administered over several weeks by a dietitian.
‘A low-FODMAP diet involves restricting all high-FODMAP foods for a period of two to six weeks,’ she says. ‘Once symptoms reduce, you’ll strategically reintroduce certain types of FODMAPs back into your diet to try to identify which particular FODMAPs are causing the symptoms.’
It’s important to figure out which FODMAPs cause digestive distress because those that don’t are an important part of the diet.
‘A lot of the high FODMAP foods feed our good bacteria and produce beneficial products that are good for our bowel health,’ says Dr Snipe. ‘It’s good for some of the bacteria to be able to ferment and produce beneficial products that help our colon to remain healthy.
‘If you’re avoiding all of them and not reintroducing them, it can result in changes to your bacterial composition that may not be beneficial for your health.’
Plus, she says there’s a lot of conditions that overlap with these sorts of gut symptoms so consulting a qualified health professional is the most effective way to identify the cause of the symptoms.
‘There are many dietary and non-dietary causes of gastrointestinal symptoms that should be investigated systematically with support from a general practitioner and dietitian,’ says Dr Snipe.
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