THINKING OF GOING GLUTEN-FREE? READ THIS FIRST
Sally Shi-po POON (Registered Dietitian)
Gluten-free diet has gained considerable popularity in the general population over the past decade. Many celebrities and athletes have acclaimed it as an effective way to better health, weight control and athletic performance. There is, however, a lack of scientific evidence to support these claims. On the contrary, there are studies suggesting that gluten avoidance in diet may not be as “healthy” as it claims.
What is gluten-free diet?
Gluten-free diet is a diet that doesn’t contain any gluten. Gluten is a protein that is found in wheat, barley, rye, malt, and oats (unless they are labelled gluten-free). These ingredients are commonly found in bread products, pasta, breakfast cereals, cakes, cookies, batter-fried foods, beer and ale. There are a number of gluten-free grains and plant foods that are suitable for those on gluten-free diet. They include amaranth, arrowroot, buckwheat, cassava, corn, flax, legumes, millet, nuts, oats labelled gluten-free, potato, quinoa, rice, sago, seeds, sorghum, soy, tapioca, and teff.
Who should follow gluten-free diet?
People who have coeliac disease should follow gluten-free diet strictly. Coeliac disease is a serious, genetic, autoimmune illness where the consumption of gluten induces damage to the small intestine and causes nutrient malabsorption. Symptoms include bloating, diarrhoea, nausea, gas, constipation, fatigue, mouth ulcers, unexpected weight loss, hair loss and anaemia. The only treatment for celiac disease is strict avoidance of gluten for life. If you think you have coeliac disease, do not remove gluten from your diet until your doctor makes a diagnosis. If you remove gluten from your diet too early, it will cause an inaccurate result for both blood test and gut biopsy.
Non-coeliac gluten sensitivity
Some people have gut symptoms when eating gluten, even if they don’t have coeliac disease. This is called non-coeliac gluten sensitivity. Symptoms are similar to coeliac disease, such as abdominal pain, bloating, and diarrhoea. Most people with non-coeliac gluten sensitivity agree that there is an improvement of symptoms after following gluten-free diet. The exact trigger for the non-coeliac gluten sensitivity remains controversial thus far. There are reports suggesting that fermentable oligo-di-mono-saccharides and polyols (FODMAP) in wheat, rather than gluten, induce the gut symptoms. The exact cause is, however, yet to be identified.
Is gluten-free diet healthy for the general population?
Not really! Although some celebrities adopt gluten-free diet for weight loss, there is no data to support similar effectiveness among people without coeliac disease. It is important to note that gluten-free does not necessarily mean low-energy. In 2017, experts from the European Society for Paediatric Gastroenterology Hepatology and Nutrition warned that gluten-free products should not be considered a healthy substitute to regular foods because they usually contain higher levels of saturated fat and lower levels of protein.
In 2017, a study published in British Medical Journal found that gluten-free diet may increase cardiovascular risk as a result of reduced consumption of hearty wholegrains. Gluten-free cakes, cookies, muffins, crackers, bread and pizza are usually made with refined carbohydrates, which are high in glycaemic index, and low in B vitamins, iron, and dietary fibre.
In addition, people on gluten-free diet were found to have significantly higher levels of heavy metals such as arsenic, mercury, lead, and cadmium than those not avoiding gluten. More research is needed to determine whether this diet poses a significant health risk in the long run. In case if gluten-free diet is needed, the best way to avoid excessive exposure to these metals is to diversify the food menu.
Does gluten-free diet improve athletic performance?
Implementation of gluten-free diet among non-coeliac athletes has become increasingly popular because of perceived ergogenic and health benefits. In 2015, a carefully designed study published in Medicine & Science in Sports & Exercise concluded that a short-term gluten-free diet had no overall effect on exercise performance, gut symptoms, perceived well-being, intestinal injury, and inflammatory responses in non-coeliac athletes. Whether avoiding gluten for a longer period of time would lead to improvements in sports performance or well-being is yet to be identified. Nevertheless, current study suggests that gluten-free diet is not a panacea. Athletes should always remember that proper nutrient intake and timing are critical components of athletic success.
Before adopting gluten-free diet…
The significance of gluten-free diet in the general population remains controversial and more research is warranted. Before adopting gluten-free diet, you should consult a dietitian to ensure that you will get all the essential nutrients from a variety of foods, including gluten-free grains, fruits, vegetables, legumes, fish, lean meat, nuts, seeds, and dairy.
If you are suffering from any gut symptoms, such as abdominal pain, bloating, or diarrhoea, you should consult a doctor for medical advice. Self-treatment or delay in treatment is undesirable.
Sally’s Nutrition Blog @ Hong Kong Tatler: https://hk.asiatatler.com/life/everything-you-need-to-know-about-going-gluten-free