Around 1 in 133 people in the US, or 1% of the population, have celiac disease - a more serious form of gluten intolerance.
Gluten is a protein found in wheat, barley, rye and triticale (a combination of wheat and rye). It acts as a "glue" in foods such as cereal, bread and pasta, helping them hold their shape. Gluten can also be found in some cosmetic products, such as lip balm, and it is even present in that nasty tasting glue on the back of stamps and envelopes.
In some individuals, consuming gluten can cause illness. It is estimated that around 18 million people in the US have some form of gluten intolerance - referred to as non-celiac gluten sensitivity (NCGS) - causing symptoms such as bloating or gas, diarrhea, fatigue, headache and itchy skin rash.
Around 1 in 133 people in the US, or 1% of the population, have celiac disease - a more serious form of gluten intolerance. In celiac disease, gluten triggers an immune response that attacks the lining of the small intestine. This means the body is unable to effectively absorb nutrients into the bloodstream, which can lead to anemia, delayed growth and weight loss.
Celiac disease can lead to other conditions, such as multiple sclerosis (MS), osteoporosis, infertility and neurological conditions if left untreated, and the only effective treatment for celiac disease is to adopt a strict lifelong gluten-free diet.
What is a gluten-free diet?
For celiacs, a gluten-free diet means avoiding all foods that contain the protein, even in the most smallest amounts.
Breads, beer, candies, cereals, cakes and pies, french fries, pastas, processed meats and soups are among some of the foods that should be avoided, unless they are specifically labeled gluten free. Oats can come into contact with wheat during production stages, so unless labeled gluten free, they should also be avoided.
There are many foods that are naturally gluten free, including fruits and vegetables, fresh eggs, fresh meats, fish and poultry (not marinated, breaded or batter-coated), unprocessed beans, seeds and nuts, and the majority of dairy products.
Many grains and starches are allowed as part of a gluten-free diet, including buckwheat, corn and cornmeal, flax, quinoa, rice, soy, arrowroot and millet. Celiacs should be careful, however, that these grains have not been mixed or processed with grains, preservatives or additives that contain gluten.
Following a gluten-free diet may have been challenging a decade ago, given that many of our staple foods contain the protein. But grocery stores are now stocked with an array of gluten-free alternatives, albeit at a higher price than gluten-containing products.
While the availability of gluten-free foods is great for people with gluten sensitivity, more and more of us without such an intolerance are turning to gluten-free products. Why? Many of us believe gluten is bad for us, even when there is very little scientific evidence suggesting it is.
'Gluten is only bad for your health if you are a celiac'
According to a survey from market research company NPD Group, almost 30% of adults in the US claim to be reducing their gluten intake or cutting the protein out completely - a proportion that is much higher than the number of people who have celiac disease.
But there seems to be limited evidence that - outside of celiac disease - gluten is bad for our health. A 2011 study, conducted by Peter Gibson and colleagues from Monash University in Australia, claimed that NCGS may be a legitimate disorder, after finding participants that consumed gluten experienced increased bloating and fatigue.
A 2013 study from the same research team, however, overturned their previous findings. "We found no evidence of specific or dose-dependent effects of gluten in patients with NCGS," the team concluded. In fact, the researchers found the bloating previously identified may be attributable to consumption of carbohydrates called FODMAPs (fermentable, oligo-, di-, monosaccharides, and polyols).
And in November 2014, Medical News Today reported on a study published in the Journal of Proteome Research, in which investigators found non-gluten wheat proteins - serpins, purinins, α-amylase/protease inhibitors, globulins and farinins - may be triggers involved in celiac disease.
Gaynor Bussell, a dietitian and spokesperson for the UK's Association for Nutrition, told Medical News Today: "Gluten is only bad for health if you are a celiac."
Lisa Cimperman, a clinical dietitian at the University Hospitals Case Medical Center in Cleveland, OH, and a spokesperson for the Academy of Nutrition and Dietetics, added: "Gluten is neither essential not detrimental to one's health or quality of diet."
Gluten has been 'popularized as a dietary villain'
As such, some nutritionists believe following a gluten-free diet without having received a diagnosis of celiac disease does not offer health benefits, but the unwarranted praise for the diet makes us believe it does.
Cimperman told us:
"There are no beneficial health effects [to a gluten-free diet]. Wheat and gluten have recently become popularized as dietary villains by a number of books and media outlets.
Unfortunately, talk show hosts and celebrities are able to amplify such messages while having little to no health or nutrition credentials. There is no research to support gluten-free diets for anyone other than those affected by celiac disease."
In fact, some experts claim following a gluten-free diet in the absence of celiac disease may actually be detrimental to health, as it can lack the nutrients needed to maintain a healthy, balanced diet. According to the Mayo Clinic, a gluten-free diet may lead to lower levels of iron, calcium, fiber, folate, thiamin, riboflavin and niacin.
Rafe Bundy, a nutritionist and spokesperson for the Association for Nutrition, disagrees, claiming it is possible to get all the nutrients you need with a gluten-free diet.
"There are many people around the world that consume a diet which is naturally gluten free or low in gluten," she said. "A good example is most of Asia, where the main staple food is rice, not wheat. It's perfectly possible to have a healthy diet which is also gluten-free diet using most standard dietary advice."
Another point that goes against a gluten-free diet, however, is that many processed gluten-free products can be higher in fat, sugar and calories than their gluten-free alternatives, which can lead to weight gain.
"'Gluten free' has achieved health halo status," Cimperman told MNT. "People believe that this term absolves the food of any other negative characteristics. The reality is that gluten-free junk food or desserts are certainly no healthier than their gluten-containing counterparts."
Are we being 'duped' into believing gluten-free is healthy?
But if this is the case, why do the non-gluten intolerant public continue to pile up their shopping baskets with gluten-free products? A survey conducted by consumer research company Nielsen revealed that sales of gluten-free products in the US rose by 16.4% in 2013-14, reaching $23.3 billion.
In sync with the earlier statement made by Cimperman, Bussell told us: "They have been duped by popular but poorly informed celebrities and media."
A survey revealed that sales of gluten-free products in the US rose by 16.4% in 2013-14, reaching $23.3 billion.
When you have celebrities like Paltrow and McCarthy openly talking about how going gluten free has changed their lives, while promoting numerous books on how to make your own delicious gluten free meals at home, it is hard not to take notice.
It is also hard not to notice the increasing array of gluten-free products available in grocery stores. But is this because the stores are bowing to the consumer demand? Or are they simply jumping on the gluten-free hype in an attempt to make more money? Bussell believes it may be a bit of both.
"It's true that grocery stores will try and bow to demand," she said. "It's a vicious circle as they may try and sell more by promoting gluten free as a good myth. On the other hand it does give a true celiac more choice other than what they can get on prescription."
Some nutritionists believe that the focus on gluten-free diets and the growing availability of gluten-free foods may also be driving awareness of celiac disease.
"Increased awareness of the gluten-free diet hopefully provides an opportunity for increasing awareness of celiac disease, the symptoms of celiac disease, the diagnosis process and the associated health implications of undiagnosed celiac disease," a spokesperson from Coeliac UK told MNT.
But is there also a worry that a gluten-free diet will be seen as nothing more than a "fad," distracting from the seriousness of celiac disease?
"There is the possibility that those who remain unaware of celiac disease fail to appreciate the seriousness of the disease," said Cimperman. "My hope is that people with celiac disease and other knowledgeable individuals will see this as an opportunity to educate."
Before adopting a gluten-free diet...
From the evidence presented in this feature, it is clear that the pros and cons of a gluten-free diet among non-celiacs need to be investigated further.
For now, it seems the gluten-free trend is set to continue. But before you go scrapping the protein from your diet - whether due to gastrointestinal problems or the desire for a change in food intake - Cimperman offers a word of advice:
"Any gastrointestinal symptoms, such as chronic or severe abdominal pain, bloating or diarrhea should be discussed with a doctor. Your doctor will need to assess for many other conditions that may be causing symptoms. Self-treating may delay proper treatment.
In addition, it is important to continue consuming gluten prior to being tested for celiac disease - following a gluten-free diet prior to being tested may result in a false negative. If you still want to follow a gluten-free diet after celiac disease or any other health problems have been ruled out, talk to a dietitian to make sure your diet contains all the essential nutrients."
Our Knowledge Center article - "What is gluten intolerance? What is celiac disease?" - provides further information on these conditions.