Sorting fact from myth about a gluten-free diet, and why it may be bad for you
For one in 100 people gluten is a poison; a further 6 per cent may suffer discomfort if they eat it; for the rest of us, there is no evidence avoiding gluten does you good, and some evidence it can cause weight gain and harm health
A few years ago, gluten-free products were virtually unheard of, but these days they’re so common on supermarket shelves it’s hard not to think of gluten as some kind of diet enemy like trans fats or added sugar.
For an estimated one per cent of the population who have coeliac disease, gluten is indeed a poison. Just a brief exposure to the protein compound – primarily found in wheat, barley and rye – can cause an immune response from the body that damages the surface of the intestines, disrupting the body’s ability to absorb nutrients from food.
For up to six per cent of the population with non-coeliac gluten sensitivity, gluten can induce gastrointestinal or extraintestinal symptoms such as mental fatigue (aka “brain fog”), lack of energy or lethargy, gas, bloating, abdominal pain or cramps, diarrhoea and even constipation.
But for the rest of the population, gluten, which gives elasticity to dough and makes bread chewy, is perfectly palatable. Yet a gluten-free diet has become trendy in recent years, much like wearable technology, athleisure, CrossFit or cold-pressed juices.
While a gluten-free diet is a critical – and only – medical treatment for people with coeliac disease, most who follow the diet do so for other reasons, such as the impression that it’s “healthier” than a regular diet, or for no particular reason at all, according to recent commentary on the fact and fiction of the gluten-free fad in the Journal of Paediatrics.
“The prevalence of coeliac disease is increasing, reflected by escalating awareness of coeliac disease in the scientiﬁc community. This increase in disease prevalence and awareness of coeliac disease, however, does not account for the disproportionate increase in growth of the gluten-free food industry,” says the commentary’s author, Dr Norelle Reilly, from New York-Presbyterian/Columbia University Medical Centre. “According to market research, consumers without coeliac disease purchase the vast bulk of gluten-free products.”
The global market for gluten-free products is valued at US$4.63 billion and is projected to reach US$7.59 billion by 2020, according to analysts MarketsandMarkets. Market analysts Technavio predict the Asia-Pacific region will be the fastest growing region for the global gluten-free food market till then.
One of the latest products to join the gluten-free gang is beer made from the world’s first WHO-approved “gluten-free” barley developed by Australian scientists.
Even makers of some products such as vegetables and Greek yogurt – which never contain gluten anyway – have added “gluten free” labels as a marketing tool.
In a 2015 Nielsen survey of 30,000 adults in 60 countries worldwide, 21 per cent of individuals surveyed rated gluten-free as a “very important” attribute when making food purchasing decisions.
Since going gluten- and grain-free, Stefanie Ross Hemshall, who owns a Hong Kong sports store chain, says her autoimmune disease and previous issues with bloating have disappeared.
Jeff Paine, a recreational cyclist, went on a gluten-free diet to lose weight. “It worked,” he says. “Unfortunately I was miserable and hungry, so now I am just fat again.”
If you’re considering jumping on the gluten-free bandwagon – or if you’re already aboard – here are some myths raised by Reilly to ponder over.
Myth: the gluten-free diet is a healthy lifestyle choice with no disadvantages
Fact: for individuals who do not have coeliac disease, wheat allergy, or non-coeliac gluten sensitivity, there is no data supporting the presumed health beneﬁts of a gluten-free diet, Reilly says. In fact, the opposite may be true in certain cases, particularly when the diet is followed without the guidance of an experienced registered dietitian or physician.
Gluten-free packaged foods frequently contain a greater density of fat and sugar than their gluten-containing counterparts. Increased fat and calorie intake have been identified in individuals after a gluten-free diet, Reilly writes. People who have switched to a gluten-free diet have become overweight or obese, become resistant to insulin or developed metabolic syndrome. The diet may also lead to deficiencies in B vitamins, folate and iron, given a lack of nutrient fortification in many gluten-free products.
Recently emerging evidence suggests those consuming gluten-free products without sufficient diversity may be at greater risk of exposure to certain toxins such as arsenic and mercury.
Myth: gluten is toxic
Fact: there is no data to support the theory of an intrinsically toxic property of gluten for otherwise healthy and asymptomatic adults and children, and certain studies have specifically demonstrated a lack of toxic effect, Reilly says.
Gluten, comprising gliadins and glutenins, is one of the many protein components of wheat. For the majority of people, gluten proteins pass through the gastrointestinal tract without leading to disease.
Theories that the increasing prevalence of coeliac disease may be attributable to augmented quantities of gluten in wheat related to breeding are not supported by literature. Some have speculated that coeliac disease, and possibly non-coeliac gluten sensitivity as well, may be on the increase as the result of processing of foods and increased per capita gluten consumption such as
through addition of vital gluten to foods.
Myth: a gluten-free diet is necessary for healthy first-degree relatives of individuals with coeliac disease, or for healthy infants at risk of developing coeliac disease
Fact: even if you have family or relatives with coeliac disease or gluten sensitivity, Reilly says a gluten-free diet is not advisable under any circumstance without first testing for coeliac disease while the person is consuming gluten in an unrestricted fashion.
Recent studies show that pooled rates of coeliac disease among first-degree relatives are about 7.5 per cent. For a small subset of patients who are guided by an experienced registered dietitian, a gluten-free diet can lead to better health and an improved quality of life.
For at-risk infants in particular, the topic of gluten introduction has been the subject of great scrutiny in recent years. The most current understanding based on long-term cohort studies in at-risk infants is that neither delaying gluten introduction from the recommended six months of age to one year, nor introducing it at four months of age alters long-term coeliac disease risk estimates.
Myth: only people with coeliac disease need to be on a gluten-free diet
Fact: there are multiple symptoms for excluding gluten from one’s diet, including non-coeliac gluten or wheat sensitivity, and wheat allergy.
Non-coeliac gluten sensitivity, the prevalence of whicih ranges from 0.5 to six per cent, is a poorly understood condition for which the clinical diagnostic criteria have only recently been clarified, Reilly writes.
Recent evidence has supported the hypothesis that certain people with sensitivity to fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (a group of poorly absorbed, short-chain carbohydrates also known as “Fodmaps”) may be misclassified as having non-coeliac gluten sensitivity.
A minority of those with gluten-related symptoms are wheat allergic. Symptoms in such patients may be immediate or non-immediate, and frequently are respiratory, cutaneous (affecting the skin) or digestive in nature. A diagnosis is done through a combination of clinical symptoms, possibly dietary challenge, lab tests for specific antibodies and prick tests. People with wheat allergy may usually safely consume other gluten-containing foods without issue.