Published on 25th April 2018


The ‘gluten-free’ label is becoming a familiar sight. Mike Murphy looks at why more people are choosing to cut out this natural protein, even without doctors’ orders 

If you have the autoimmune condition coeliac disease (CD), you need to avoid gluten for life. That, according to current medical knowledge, is nonnegotiable. But with only an estimated one in 100 of us being affected by CD, the rise in popularity of gluten-free (GF) products doesn’t seem to add up.

Gluten-avoidance is considered by many to be something of a fad, but it is now estimated that eight per cent of the UK population avoids gluten1 as part of a ‘healthy’ lifestyle — something which has not gone unnoticed by food manufacturers, who have responded with gusto. In 2015, 12 per cent of new food products launched in the UK carried a GF claim,1 with GF breakfast cereals leading the charge with sales growing by 79 per cent a year since 2010.2

Gluten and coeliac disease

CD is a condition that often, but not exclusively, occurs in genetically susceptible individuals whereby gluten (a protein component found in wheat, barley and rye) triggers an autoimmune reaction that can damage the lining of the small intestine, leading to symptoms such as abdominal pain, vomiting, diarrhoea, weight-loss and, eventually, malnutrition. Sufferers may also develop a separate condition called dermatitis herpetiformis, which causes an itchy rash with blisters that burst when scratched. Because CD is an autoimmune condition and not an allergy or intolerance, sufferers will not have anaphylaxis or symptoms usually associated with allergic reaction. Instead, they are likely to have vomiting and diarrhoea, with longer-term damage occurring on the inside. Although following a GF diet will enable the gut to heal, re-introducing gluten will cause the immune system to react again, damaging the gut microvilli, which is responsible for absorbing nutrients.

Prior to the millennium, the prevailing medical opinion was that CD was a very rare disorder, but studies have since demonstrated that it is, in fact, one of the most common genetic diseases of humankind affecting almost one per cent (1:133) of the population.3

The treatment option — total exclusion of gluten — may seem simple but, as CD sufferers will attest, that’s easier said than done. Today, on top of the obvious culprits like cereals, pasta and bread, gluten can be found in everything from sausages and beer, to soy sauce, salad dressings and even some cosmetics,4 not to mention foods that inherently do not contain gluten but which may have been contaminated by factory processing. For somebody with CD, this can be a real problem because it only takes trace amounts to cause harm.5

Kathryn Miller, Coeliac UK head of food policy, told Optimum Nutrition that CD is well understood and clearly defined by the presence of specific genes, the abnormal immunological response to gluten and associated production of IgA antibodies. “Less is known about what triggers the reaction to gluten in those predisposed and why; although 40 per cent of the population have the required genetic make-up, the disease affects only one per cent,” she says.

Miller explains that although the symptoms of CD can appear or be identified at any age after including gluten in the diet, most people are diagnosed in their forties or fifties.

While eliminating gluten completely from the diet is the only known treatment for CD, there has, however, been recent media attention on tablets that are claimed to help break down gluten. But Miller says that it is not advisable for individuals with CD to take any kind of supplement as a substitute for a GF diet. “A number of enzyme supplements are available which claim to break down gluten when they are taken with foods, and are marketed to people with coeliac disease and/or gluten sensitivity,” she says. “Independent research of five currently available digestive enzyme supplements shows that they are ineffective in degrading the toxic parts of gluten. The only current treatment for coeliac disease is a strict gluten-free diet for life.”

What is gluten?

Gluten is found in grains, which are seeds from cereal grasses that have evolved to survive from season to season. Easily transported and stored for considerable periods without spoiling, they have become a commodity upon which we have grown dependent for the majority of our food supply.6 Wheat was the earliest recorded grain to be cultivated and is a staple food for more than a third of world’s population. The wheat kernel is mostly starchy carbohydrate with roughly 10-12 per cent being protein.7 Although there are hundreds of different proteins found in wheat, 80 per cent of the protein content is made up of two specific protein molecules (also found in barley and rye), gliadin and glutenin, which combine to form what we call gluten. As the name implies, gluten has glue-like properties that give dough its stretchy consistency and enables bread to rise by trapping the carbon dioxide gases produced by the yeasts feeding on the sugars, creating its spongy texture.

Although coeliac disease can be identified at any age after including gluten in the diet, most people are diagnosed in their forties or fifties

In order to digest protein, stomach acid and enzymes released from the pancreas go to work to break down the protein in our food into peptides and individual amino acids, which are then absorbed into the bloodstream and utilised by our cells. There is a view, however, that gluten is a difficult protein for humans to digest and that gliadin, a large component of gluten, is resistant to digestive enzymes.8

The lining of the small intestine, where we absorb nutrients from our food, is only one cell thick. This layer of cells, known as the epithelial barrier, maintain tight junctions between themselves in order to absorb individual nutrients while preventing whole food particles and other toxins from entering the blood stream. Some research has shown that “irrespective of the genetic expression of autoimmunity”9 gliadin triggers the release of a compound called zonulin from these cells, which is thought, in some individuals, to cause intestinal permeability, commonly known as ‘leaky gut’.10

The problem begins when unwanted molecules and toxins leak into the bloodstream, activating a response from the immune system in the form of inflammation and production of gluten-associated antibodies; the job of which it is to seek out any gluten molecules in the blood and tag them for destruction. It has been suggested that this immune response is also a causative factor in various autoimmune diseases; although, according to the NHS, there is currently little evidence to support this. It does, however, acknowledge that some conditions and medications can be associated with increased intestinal permeability.11

Gluten and autoimmune diseases

As people search for answers to their health problems, there is a growing suspicion that gluten could be implicated in various diseases. The NHS advises that “a number of other health conditions can increase our risk of developing coeliac disease”10 such as type 1 diabetes, thyroid conditions, ulcerative colitis, and neurological conditions affecting the brain and nervous system. However, it also states: “It’s unclear whether these health conditions directly increase your 

risk of developing coeliac disease, or whether they and coeliac disease are both caused by another, single underlying cause”,10 suggesting that it does not propose that gluten is a causative factor in these other diseases. However, lack of consensus has not prevented gluten from being considered a primary suspect in various autoimmune illnesses.

What we do now know is that CD is actually a systemic disease that can manifest anywhere in the body.12 An impact of CD is that it can cause malabsorption of nutrients, leading to conditions such as osteoporosis and anaemia: for every CD-sufferer with gut-related symptoms, there are eight who have related symptoms outside the gut.13 For example, there are studies as far back as the 1960s connecting CD with neurodegenerative diseases and disorders of the brain.14 And, suggesting that gluten might impact other diseases, one study into individuals aged between three and 57 and diagnosed with both CD and attention deficit hyperactivity disorder (ADHD) found a GF diet was associated with significant improvement in all markers of behaviour.15

The debate over whether gluten is a factor in diseases other than CD continues, but in 2012, one group of scientists agreed that there was a spectrum of gluten-related disorders beyond CD, referred to as non-coeliac gluten sensitivity (NCGS).16 The symptoms of NCGS can mimic those of CD but without the autoimmune response and subsequent tissue damage to the gut lining and potentially other tissues in the body, making its clinical diagnosis challenging. In fact, today the only diagnostic criteria of NCGS is the reported improvement of symptoms when gluten is excluded from the diet. A recent trial found that NCGS is the cause of irritable bowel syndrome (IBS) in 20 per cent of IBS sufferers.17


Recent research, however, does indicate that gluten could, in some cases, be a red herring. In 2011, Professor Peter Gibson, head of the department of gastroenterology at Monash University, Victoria, Australia carried out a doubleblind, randomised, placebo-controlled study into the effect of gluten on individuals without CD. The study concluded that “non-coeliac gluten intolerance may exist, but no clues to the mechanism were elucidated”.18

Two years later, Gibson’s team carried out a new study on NCGS subjects with IBS, but this time incorporated the low FODMAP diet, which his team had developed to relieve IBS. FODMAP refers to fermentable oligosaccharides (e.g. fructans found in wheat, rye and some vegetables); disaccharides (e.g. lactose, found in milk); monosaccharides (e.g. free fructose found in honey and some fruit); and polyols (e.g. sorbitol and mannitol),19 all of which are carbohydrates and sugar alcohols found in everyday foods, but which are not absorbed easily by the gut and so begin to ferment, causing painful bloating and gas.

This new study found no evidence that gluten affected NCGS subjects. But what it did reveal was that in “all participants, gastrointestinal symptoms consistently and significantly improved during reduced FODMAP intake” and that “NCGS, as currently defined, might not be a discrete entity or that this entity might be confounded by FODMAP restriction”.20 

Despite this, however, Gibson told Optimum Nutrition that this did not mean that the NCGS-debate was over. “

It tells us that it is likely that, for most people who believe they are gluten intolerant, without coeliac disease, gluten is not the cause,” he said. “It may be other components of wheat, rye and barley. It does not tell us that gluten sensitivity does not exist.”

Because of the findings, however, Gibson says that NCGS individuals who have IBS might benefit from a low FODMAP diet rather than a GF diet. “Wheat, rye and barley are rich sources of FODMAPs, especially as they are generally eaten in large amounts — e.g. bread, pasta,” he says. “Most people with NCGS have IBS and lowering FODMAP intake may benefit them greatly. This was shown in the 2013 study.” Despite the level of restriction on a low FODMAP diet, he also said that it was easier to follow than a GF diet.

As for the suggestion that there could be a link between gluten and other autoimmune diseases, Gibson says that there is no scientific evidence for this and that it would be difficult to propose a biological mechanism. “There are other components of wheat that are 

being investigated for their effects on the immune system,” he says. “It would be good to have well designed studies to address this issue, but such studies would be difficult.”

A happy, unexpected side effect is that I have more mental clarity and enhanced memory and recall,” she says. “I feel like I am looking healthier and more fit due to giving up gluten. A family member who hadn’t seen me for a few months remarked about it.”

Gluten-free non-coeliacs

Many, however, feel they do not have time for science to provide the answers with peer-reviewed studies.

Felicia Kwaku, a senior nurse, says that she had a very sensitive gut for many years, despite being given the ‘all clear’ from CD. She would “flush” if she ate “anything white”, and had a painful, tender stomach, changeable bowel movements, and often felt bloated. In 2013 she was on proton pump inhibitors and had developed a bleeding duodenal ulcer and Helicobacter pylori infection.

She was advised by a gastroenterologist to cut out tomatoes and coffee but, after consulting a nutritional therapist, excluded gluten from her diet. Since cutting out gluten she says she has less bloating, feels less heavy and more energised. But vigilance is key, she says. “I can’t take anything for granted as gluten winds up in places that I would never have expected.”

Kari Nogle has also recently cut out gluten in an attempt to help her thyroid. “Upon discovering I had thyroid nodules… I have committed to at least a year without gluten to see if it helps save my thyroid. “

The first two weeks were especially difficult. Many of my old go-to foods contain gluten, and I didn’t have replacement foods in place yet. Plus, I wasn’t used to having to think before putting food in my mouth. I made a few involuntary mistakes while cooking for my family in the beginning, and sometimes you just forget that certain items contain gluten, such as soy sauce. Other mishaps happened when I was drinking… I ploughed into some sourdough bread on three occasions during ‘happy hour’. Needing some comfort foods in the beginning, I substituted sugary foods for gluten foods. I have weaned myself from those. Now my concern is that glutencontaining food additives are sneaking in occasionally without me knowing.”

Despite not knowing yet whether her new regime has helped her thyroid, Kari says that she feels much healthier without gluten. “A happy, unexpected side effect is that I have more mental clarity and enhanced memory and recall,” she says. “I feel like I am looking healthier and more fit due to giving up gluten. A family member who hadn’t seen me for a few months remarked about it.”

She has, however, noticed an improvement in her ability to swallow — something that had been affected by her thyroid problem. “I’m very encouraged by the improvement in my ability to swallow vitamins. It was getting to the point where I was avoiding taking vitamins because they would sit in my throat right next to the thyroid for up to 10 minutes. Now I can take several vitamins with only a slight, quicker sensation of them getting stuck.”

However, Kari remains concerned that gluten might prove not to be the culprit for her condition. “I won’t know for several months when I am resonogramed. If the size of the nodules has not decreased, then I’ll remove other possible culprits from my diet.” 

Also, a sample of one person without controlling for other factors cannot be considered ‘proof’. Regardless, she says that she thinks she will continue to be gluten-free. “After four months, it isn’t that big of a deal going without bread, cereal, and cookies.”

Research links low-gluten diet to higher diabetes risk

It was recently widely-reported that gluten-free (GF) diets might increase the risk of developing type-2 diabetes. The news headlines had followed a press release from the American Heart Association, which announced the findings of a study by researchers from Harvard University, which had been presented to the association’s Epidemiology and Prevention / Lifestyle and Cardiometabolic Health 2017 Scientific Sessions.

The Harvard team had analysed 30 years of data from 199,794 participants, finding that while most participants had gluten intake below 12g per day, those who ate the most gluten within this range had a 13 per cent lower risk of developing type-2 diabetes, compared with those who ate approximately fewer than 4g per day. Perhaps crucially, the study had found participants who ate less gluten also tended to eat less cereal fibre, which can help protect against type-2 diabetes.

“We wanted to determine if gluten consumption will affect health in people with no apparent medical reasons to avoid gluten,” said Geng Zong, PhD, a research fellow in the Department of Nutrition at Harvard University’s TH Chan School of Public Health in Boston, Massachusetts.

“Gluten-free foods often have less dietary fibre and other micronutrients, making them less nutritious and they also tend to cost more. People without coeliac disease [CD] may reconsider limiting their gluten intake for chronic disease prevention, especially for diabetes.”

However, while this was a large study, cause and effect cannot be assumed. The study did link low-gluten diets with type-2 diabetes, but the study used observational, self-reported data. None of the participants followed a GF diet.

Participants completed food-frequency questionnaires every two to four years. The researchers then used the data to estimate gluten intake according to consumption of pastas, cereals, pizza, muffins, pretzels, and bread.

Self-reported data reflect what participants remember or choose to record at the time, and so it is difficult to say how reliable this is. Also, the study did not take into consideration other factors such as overall diet and lifestyle. We do not know whether those who went on to develop type-2 diabetes ate a healthy diet in general, whether lifestyle factors increased risk of illness, or whether they had a genetic susceptibility to diabetes. We also do not know the reason for participants eating 

fewer foods with gluten, which could have provided interesting insights.

However, the findings do raise the question as to whether a GF diet is a healthy diet. The researchers may suggest that people without CD might reconsider going GF, but people with CD have no choice: and faced with the health problems that CD can lead to, the additional threat of type-2 diabetes is concerning.

Interestingly, studies have also found that following a GF diet has a marked effect on the microbiome. This is thought to be because fibre, which provides food for our gut bacteria, is reduced when gluten is cut out. It has been suggested that individuals with CD should increase their intake of fibre and prebiotic foods to compensate for this loss to the microbiome. What this may mean is that simply replacing wheat, barley and rye products with GF products may not be helpful. Increasing prebiotic foods such as onions, garlic and leeks, and fermented foods such as kefir and sauerkraut should be beneficial along with consuming grains such as quinoa, amaranth, buckwheat and brown rice.

Demand for GF products is growing. It is a phenomenon that has led to much wider choices for people who know for certain that they must not eat gluten

Growing trend

Because of individuals like Felicia and Kari, the demand for GF products is growing. It is a phenomenon that is welcomed by Kathryn Miller of Coeliac UK because this has led to much wider choices for people who know for certain that they must not eat gluten. “As demand for gluten-free products has increased, we have seen improvements in availability of gluten-free foods in shops and restaurants as well as more variety and better quality products which benefits consumers with coeliac disease. We’ve also seen increasing media attention around the gluten-free diet, which is positive for awarenessraising amongst the general public and in food businesses like restaurants.”

But, says Miller, diagnosis rates for CD are still very low and so Coeliac UK wants to try to find the “estimated half a million people with coeliac disease who don’t yet know they have it”.

She says: “Our diagnosis campaign aims to help improve diagnosis rates and signpost people to their GP to get tested before cutting gluten out of their diet. Once on a gluten-free diet, the testing doesn’t work so it is really important to get tested first. There is a self-assessment questionnaire available which advises whether it’s recommended that you get tested, available at“

Coeliac UK is also campaigning to keep NHS support for gluten-free staple food to protect vulnerable groups due to the higher cost and limited availability of gluten-free staple food like bread.”

However, as Professor Gibson’s research has shown, for non-coeliacs, gluten may not be the enemy. So individuals who feel that they might benefit from going GF may wish to discuss it with their GP first. And where CD is not the problem, it may also be worth investigating FODMAPs to see if there is a food on that list which is causing problems.

Following a GF diet is not easy and, in the long run, may not be worth the inconvenience and expense. But if you do choose to cut gluten from your menu, look for wholefood replacements that will keep you nourished.

For more information see:
For more information on coeliac disease visit: 

Additional reporting by Maggie Charlesworth



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