Saturday 15 December 2018

Non-coeliac athletes eye gluten-free diet for edge

Catherine Norton

Gluten-free (GF) used to be a diet followed exclusively by coeliacs; people with an autoimmune disorder of the small intestine that requires gluten to be completely eliminated. But there has been an explosion in gluten-free diet popularity that has surpassed even the low-carb trend and it shows no sign of decelerating.

We know that among the general population, gluten avoidance has become prevalent primarily as a result of self-diagnosed bowel-related disorders. People with symptoms associated with irritable bowel have dabbled with many different dietary restrictions in the belief that these may alleviate symptoms. However, many without abdominal complaints have also elected to adopt dietary restriction under the premise that a wheat or gluten-free diet, for example, is healthier or can aid weight loss.

Many non-coeliac athletes (especially endurance athletes) have also begun to adopt this diet. Some say they remove gluten from their diet to control weight. Others follow the diet to reduce inflammation.

Widespread beliefs about GF diets among athletes emphasise that gluten removal is healthier, reduces GI distress, reduces inflammation, and improves athletic performance. Regardless of the reason, the question is: should non-coeliac athletes go gluten-free?

Most sport-nutrition professionals have become aware of, and experienced, the explosion of GF diets, yet do not have adequate scientific evidence quantifying or qualifying this diet amongst athletic populations. In one of the first studies investigating the phenomenon of gluten-free diets in non-coeliac athletes, researchers at the Canadian Sport Institute Pacific tracked non-coeliac competitive cyclists following gluten-free diets and those with gluten in their diets, and compared results.

The findings were that there was no difference in athletic performance, perceived GI distress, inflammatory markers, intestinal damage or overall well-being between the two groups. These findings do not support the perceptions that a GF diet may have an ergogenic effect or health benefits in non-coeliac athletes.


Despite this fact, many athletes report anecdotal benefits. Could this perceived benefit be attributed to blind faith? The 'belief effect' can be very powerful, with some researchers suggesting that the belief in an intervention can improve performance by one to three per cent. This may be the case but more often than not the adherence to a GF diet will result in changes to nutrient intakes and not just gluten avoidance.

Keith Earls and Gerhard van den Heever take a breather during the Munster squad training session in Limerick this week. Photo: Sportsfile
Keith Earls and Gerhard van den Heever take a breather during the Munster squad training session in Limerick this week. Photo: Sportsfile

Eliminating wheat, oats, barley and rye helps reduce the processed food intake when done correctly. Replacing bread, pasta, pastries, cereals, pancakes, savoury snacks and crackers with healthier alternatives (gluten-free or not) may be the reason for increased perceived benefits of the GF diet.

Following a gluten-free diet can promote the consumption of more nutrient-dense, whole-food choices. This could mean that the perceived benefits of a GF diet may be due to consuming less refined carbohydrates and increasing fruit and vegetable intake rather than the removal of gluten.

There are some caveats. Adopting a GF diet without appropriate nutrition advice may be associated with increased expense, inadequate intake of some micronutrients, including B vitamins, fibre and iron, as well as compromised gut health through reduced beneficial gut bacteria populations. These issues have the potential to pose problems for athletic populations and the general public.

Self-prescribed GF diets can be risky, not only because this may restrict food selection, but because it could also result in overlooking the underlying causes of GI distress if appropriate medical or nutrition advice is not sought.

An athlete's diet is a key element to training adaptations and athletic performance, and all elements affecting nutrition intake must be considered when deciding to adopt a GF diet for non-medical reasons.

Given the restrictive nature of this diet and the unknown effects of long-term adherence to a GF diet in non-coeliac athletes, further research in this area is essential to determine the effects of a GF diet on parameters of exercise performance and gut health.

Always seek professional advice before adopting dietary restrictions.

Dr Catherine Norton

is a Performance Nutritionist

with Munster Rugby

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