It's the stuff dreams are made of - albeit the nightmares of many an athlete: gluten has become an object of fear not only in hip, vegan urban circles. Even more and more cyclists are trying to avoid the cereal ingredient, also known as "gluten protein". Tour dominator Chris Froome, for example, avoids gluten wherever possible.
According to sports physicians and sports science studies, more than 40 per cent of competitive athletes in some endurance disciplines now abstain from gluten, which is made up of proteins and helps bread dough to rise during baking, for example. Avoiding gluten means avoiding foods containing wheat, rye, spelt, oats, barley and other grains. Many people voluntarily avoid gluten in the hope that this will lead to a healthier diet - and better athletic performance.
But as is the case with nutrition: while some rave about it, others are sceptical. "I've noticed that there's a lot of hype surrounding the topic," says Daniel König, a sports physician at the University of Freiburg who is in contact with many top athletes. Far more athletes abstain from gluten than would be expected from a medical perspective. "The athletes almost always make the diagnosis themselves - and there is rarely a medical review. Whether there are actually positive effects is usually not measured." So is it perhaps more of a trend - which is also significantly more expensive than a conventional diet?
From a medical point of view, there are two groups of people who should avoid gluten in their diet: On the one hand, there is the group that suffers from coeliac disease - in this country, the proportion of people affected is estimated at around one per cent. In people with coeliac disease, the mucous membrane of the small intestine becomes chronically inflamed. The disease does not develop as a result of gluten consumption; it is an autoimmune disease with presumably hereditary - but also other - triggers.
In addition, the term "gluten sensitivity" is becoming increasingly established in medicine for those people in whom neither an allergy nor coeliac disease can be found, but in whom physical suffering is reduced by avoiding gluten. It is not known exactly how many people this affects. However, their symptoms are known: headaches, skin problems, nausea, vomiting, diarrhoea and flatulence are the most common.
FAST EVEN WITHOUT GLUTEN
Patrick Konrad, a professional with the German team Bora, has proven that you can also compete in the world's toughest cycling race with coeliac disease: The 25-year-old Austrian finished the 2016 Tour de France in 65th place overall. He had only been diagnosed with the intestinal disease the previous year. Until then, he had been eating as cyclists traditionally do: with large amounts of carbohydrates. For a long time, he didn't even realise that something was wrong: "I used to have problems with my bowels and thought it was normal when you sit for hours on end, train hard and eat a lot," recalls Konrad. However, when medical examinations revealed a lack of iron and folic acid, he went to see a specialist - who diagnosed Konrad with the disease. This was followed by a period of adjustment lasting around three months, a learning phase. "You have to pay attention to everything, because many supposedly gluten-free products are contaminated," explains Konrad. He now manages well without the cereal gluten, eating rice cakes instead of muesli bars. His intestinal problems have disappeared. Konrad has to give up gluten - but he realises that many of his colleagues are also interested in the topic, without any medical indication.
This is the case for Paul Voß, Konrad's team-mate. Like many professionals, the 30-year-old also deals with nutritional issues. However, he has neither coeliac disease nor gluten sensitivity. He has not yet had this tested because: "I would be afraid of the results if I were tested for intolerances," says Voß. He admits that a few years ago he was still amused when his team-mate at the time, Linus Gerdemann, ate rice instead of pasta. But Voß also became increasingly sensitised. He realised that he had problems with digestion and regeneration after large portions of pasta. He then changed his diet - at least at training camps and before important competitions - and eliminated wheat and other gluten-containing products - and has benefited from this ever since, he says. He also has his weight under control: "I hardly snack any more." Wheat biscuits or reaching for a packet of muesli: you can't do that because they contain gluten.
ALTERNATIVES TO WHEAT
"The demand for gluten-free food is pretty high right now," Jeaun-Mari Breytenbach, the South African team chef for Patrick Konrad and Paul Voß, has also realised. That's why she now mostly cooks gluten-free and wheat-free - she uses quinoa and wholegrain rice or at least egg noodles - and avoids sugar in starters, main courses and desserts. She publishes her recipes on the Internet. According to Breytenbach, cutting out gluten is not just about reducing symptoms, but also about using alternative foods to create a healthier diet - for example by increasing protein intake.
Breytenbach is in good company with this view. The current Cannondale team has been gaining experience with a gluten-free diet for many years; team boss Jonathan Vaughters is a self-confessed pasta fan and has had his team eat gluten-free since 2010. One of the main arguments in favour of going gluten-free is the theory that without gluten, inflammation in the intestines can be reduced and regeneration improved, which in turn benefits athletic performance. The former Team Sky chef, Nigel Mitchell, is also considered an advocate of voluntary gluten-free eating; he is said to have helped Bradley Wiggins to build up his form and now, fittingly, cooks for the Cannondale team.
German cyclist Matthias Schindler, whose big goal is the 2020 Paralympics, is less concerned with improving his performance and more with his health. Since an unsuccessful tumour operation, the 34-year-old has been completely paraplegic; he was initially in a wheelchair, had major weight problems and then changed his diet - partly because the development of tumours is often associated with diet. Today, he avoids foods containing gluten because he believes that wheat products are full of problematic substances. Schindler never consciously suffered from gluten consumption and did not have intestinal cramps or diarrhoea like other athletes. But he is certain that he benefits from not eating gluten. And he has lost weight - 25 kilograms since his peak weight.
FEEL BETTER, ACHIEVE MORE
For athletes like Schindler, the Dr Feil research group is an important source of inspiration. The association of researchers from the fields of sports science, medicine, biology and physiotherapy has been campaigning against traditional dietary rules for years. The founder of the team, Wolfgang Feil, is the author of the book "Die F-AS-T Formel: What Successful Athletes Do Differently" - and he firmly believes that gluten should be an important issue for athletes. It is known from studies that gliadin - one of the two gluten components - promotes inflammation and increases intestinal permeability. "So there is the potential for allergies and inflammation."
From this perspective, it is a real problem substance for performance-orientated athletes, because those who do a lot of sport need a lot of energy - and those who top up with wheat products find themselves in a dilemma, according to Feil: "Many people overdo the amount of wheat they consume. The intestine is then permanently confronted with greater permeability and is more likely to become inflamed - and this leads to regeneration problems and greater susceptibility to injury." The biologist and sports scientist advises anyone experiencing work-related stress who still wants to achieve sporting goals to avoid gluten completely during such a phase - even without a medical diagnosis.
Sometimes it's just a question of feeling, as with Timo Büttner, who works in a bike shop and has successfully taken part in the Alpenbrevet or the TOUR-Transalp as an ambitious amateur cyclist. The 41-year-old not only eats a gluten-free diet, but also a vegetarian one - since undergoing heart surgery seven years ago, he has focussed on healthy eating. He has been cutting out gluten-containing foods for three years - his wife has also joined in and they even bake their own bread with alternative flours. "It makes us feel better," says Büttner.
The only question is: Is this feeling a placebo effect - or can the effect be medically proven? And doesn't it really matter as long as people can cope better with it?
Professor Daniel König from Freiburg is rather cautious. When people up and down the country talk about the benefits of giving up gluten, he counters: "The conclusion that a gluten-free diet generally improves performance cannot be proven. There is no evidence that people without irritable bowel syndrome benefit from going gluten-free." For example, a recent Australian-Canadian study found a lack of scientific evidence for the "hype". Christine Graf from the Institute of Exercise and Neuroscience at the German Sport University in Cologne has also noted the anti-gluten trend among athletes and considers it "not appropriate at present".
POSSIBLE CARBOHYDRATE DEFICIENCY?
Daniel König even warns that omitting wheat products containing gluten, for example, can even lead to problems if they are not replaced in a targeted manner: this could result in a lack of carbohydrates, but also of vitamins B1 and B6, zinc and selenium. Anyone who is used to eating carbohydrates from cereals must first learn how to replace the corresponding amounts from alternative sources - otherwise there is a risk of a lack of energy. This effect can certainly be used to lose weight, but there is also a risk here. Graf also points out that gluten-free alternative products often contain higher levels of salt and fat.
The views are therefore controversial. Wolfgang Feil believes that university research in Germany is five years behind the times. "Wheat is not a good food," he says. However, not all scientists are convinced by the arguments of Dr Feil's research group on the subject of gluten. DSHS Professor Graf says: "The data situation is actually scientifically inconsistent."
KNOW OR BELIEVE?
So is giving up gluten just a question of faith? For some, it probably is. But at least the fronts are not as hard as one might initially expect. Physician Daniel König, for example, will not talk any of his patients out of a gluten-free diet if they feel more comfortable or at least feel their performance has improved. And Wolfgang Feil doesn't necessarily preach the complete avoidance of wheat, rye or spelt either. "You shouldn't see things in black and white, but rather realistically assess the dangers of gluten."
You can still eat a pizza or a sultana bun - but you shouldn't permanently eat all carbohydrates from wheat alone, says Feil. When in doubt, even the wheat critic believes that it is even better to consciously stick to gluten-containing foods from time to time. Because otherwise you wean yourself off it - which can then lead to major problems for gluten-free athletes in competitions, for example when it comes to supplying them with bars.
One thing is certain at the moment: it is an attractive market. Alongside the mass markets for conventional foods, niches are opening up in which people are paying significantly more for the expected benefits. Professional cyclist Patrick Konrad also recognises the problem. Diets become significantly more expensive if they are consistently gluten-free; even the alternatives from the supermarket, such as gluten-free pasta, cost significantly more than standard pasta. "It costs brutally more money if you consistently pay attention to your health when eating," observes handicap athlete Matthias Schindler. Professional and amateur athletes alike are not only faced with the question of whether a gluten-free diet improves performance or not, but also whether they want to pay the price for - actually or supposedly - healthier food. At the moment, the answer for many athletes is probably: definitely.
THIS IS GLUTEN
Gluten is a mixture of proteins in some types of grain, a collection of ethanol- and water-soluble proteins. In wheat, for example, gluten consists of gliadin and glutenin, two storage proteins. Gluten is found in spelt, wheat, barley, rye and other cereals. Due to its special composition, oats can be tolerated by coeliac patients if they are grown and processed separately. However, oat products from the standard range are often contaminated with residues of wheat or other cereals.
GLUTEN-FREE ALTERNATIVES
If you want to live gluten-free, there are many alternative grains and other products to choose from. Popular choices include amaranth, buckwheat, millet, corn and quinoa. Like rice, potato is a general substitute food with a high carbohydrate concentration - which makes it a good alternative to wheat pasta. Soya also plays an important role in the gluten-free diet.
COELIAC DISEASE AND SENSITIVITY
In many cases, coeliac disease can be diagnosed with the help of blood tests. Here, certain antibodies in the serum are detected in the laboratory. Even though there are now over-the-counter self-test kits available, experts advise going straight to the doctor if coeliac disease is suspected. The diagnosis is confirmed with tissue samples from the small intestine. Unlike coeliac disease, gluten sensitivity is not an autoimmune disease, but an intolerance. It cannot be diagnosed by blood or tissue tests, but by eliminating gluten from the diet and observation. If your well-being improves when you avoid gluten, you can assume that you are sensitive.
