Food fadism: exposing the gluten myth
Geoff Winestock
Foods labelled as gluten free are proliferating in restaurants and even command whole shelves in Coles and Woolworths. Actor Gwyneth Paltrow has just published yet another gluten-free cookbook titled It’s All Good. Dinner parties are aborted because dishes are found to contain offending gluten-laden ingredients such as bread crumbs, pasta or soy sauce.
Yet two studies in Melbourne last year suggest that apart from a fairly small group of people there is no evidence that gluten does any harm.
Gluten, a type of protein found in the grains wheat, barley, rye and oats, can indeed be a serious problem for about 1 per cent of the population who suffer from coeliac disease.
In these people, gluten triggers a toxic reaction that damages the lining of the guts, killing the little hairs or villi that absorb nutrition. Over time, coeliacs who keep eating gluten are much more likely to develop a range of really nasty problems such as diabetes, rheumatoid arthritis, osteoporosis, infertility and lymphoma. And it can lead to total gut failure resulting in malnutrition and even death.
This is all well understood but the argument in medical circles has been over whether non-coeliacs should also go gluten-free. There are many people, mostly women, who complain that eating gluten makes them feel bloated, funny in the tummy or down and lethargic.
They are driving the gluten-free market and causing all that fuss at dinner parties. One survey found 10 per cent of people said they were avoiding or reducing their gluten intake because, like Paltrow, they think it is bad for them.
But is there such a thing as non-coeliac gluten intolerance or is it just another self-indulgent food fad?
Jess Biesiekierski, who completed a PhD at Monash University, based at Eastern Health Clinical School, Box Hill Hospital in Melbourne, was part of a research team that created a stir two years ago by giving the first clinical evidence that gluten might cause gastrointestinal symptoms in people without coeliac disease.
The double-blind randomised trial gave gluten-free and gluten-laden food to 34 non-coeliac patients who complained of what is known as irritable bowel syndrome, that is chronically bad tummies. It found that their symptoms improved if they gave up gluten.
When it was published in the American Journal of Gastroenterology in 2011 it gave a shot in the arm to the gluten-free industry. Gluten intolerance or sensitivity was validated.
But Biesiekierski now says the results were always tentative and the test found no mechanism such as markers of inflammation or immune response to explain the impact of the gluten. Late last year, she presented two follow-up studies at the Australian Gastroenterology Week in Adelaide.
The tests were redesigned to see if it was gluten or something else causing the problems. One test of 37 people looked at a high gluten, low gluten and gluten-free diet while in the second arm of the test 22 patients were put on a gluten or gluten-free diet. The result was that no gluten-specific gastrointestinal effects were reproduced.
The follow-up study is now being reviewed for publication in the American Journal of Gastroenterology so the debate is likely to start taking a very different turn. Biesiekierski says that as of now non-coeliac gluten sensitivity is not well understood. It may yet exist but more research is needed.
“We do not know the prevalence, mechanism, diagnostic procedure or practical issues of treatment,” says Biesiekierski.
Given this uncertainty, Biesiekierski is worried that people are rushing onto gluten-free diets without adequate advice. About 45 per cent of people who self-diagnose as gluten intolerant put themselves on a gluten-free diet.
But the risk is that if they cut out all the four gluten grains, their diet will be too low in fibre and vitamin B, causing other nutritional problems.
As a registered nutritionist, Biesiekierski’s advice for people who think they feel bad after eating high-gluten foods such as bread or pasta or drinking beer is first to get checked for coeliac disease. In fact, about two-thirds of people who say they have “gluten sensitivity” have not been checked for coeliac, so that is a good first step.
Although it is possible to have coeliac disease without showing any symptoms, usually coeliac sufferers experience general stomach problems such as indigestion, a bloated feeling, diarrhoea or constipation and lethargy.
Doctors say men are especially reluctant to be tested, and tend to tough out the symptoms. A simple blood test and gene screening can rule out the disease in about two-thirds of cases. After that, to tell for sure, you need to take a test called an endoscopy involving a light general anaesthetic and biopsies of your small intestine.
But doctors say women are twice as likely as men to take the test. It takes on average about 11 years from the time men first complain of symptoms for them to start keeping the gluten-free diet. Maybe they are reluctant to adjust their diets. It is true that gluten-free beer tastes “weak” to put it politely. Yet doctors say delay will only aggravate the consequences in later life.
“The severity of the symptoms is linked to how long it takes you to change your diet,” says Jason Tye-Din, a gastroenterologist from the Walter and Eliza Hall Institute and chair of Coeliac Australia.
After excluding coeliac disease, Biesiekierski says some changes to diet might be useful for people with chronically bad tummies. While the clinical evidence that gluten causes problems is almost non-existent, there is strong evidence that some foods that contain gluten also contain another group of substances for which there is strong evidence they can cause gut problems.
These so-called short-chain carbohydrates, known as FODMAPs (Fermentable Oligosaccharides, Monosaccharides And Polyols), are difficult for the gut to absorb. Bacteria make them ferment, which is what gives you the bloated feeling and pain, although not the long-term damage linked to coeliac disease.
There are many kinds of FODMAP in many different foods and they disagree with some people more than others. Fructans are in wheat and rye bread but also in garlic and onions. There is excess fructose in pears and honey and sugar polyols in stone fruits and some artificial sweeteners. Another FODMAP is lactose in milk.
Since bread and pasta are high in fructans, they could well be causing irritable bowel syndrome, but it has nothing to do with gluten. So many people may be mistaking gluten sensitivity for a problem with FODMAPs.
For many it might make sense to buy gluten-free products but it has nothing to do with their absence of gluten. It is because coincidentally many products that are gluten-free are low in FODMAPs. Gluten-free pasta and bread, for instance, are usually made from corn, rice or quinoa, which contain no fructans.
“It is likely, therefore, that ‘gluten restriction’ will automatically reduce a patient’s dietary FODMAP intake and this may explain why so many people report feeling better on a gluten-free diet,” Biesiekierski says.
One other consideration is that although prices have come down thanks to the gluten-free fad, gluten-free foods are very expensive, so check if there are any alternatives. Monash University has produced a low FODMAP diet, which is available in pamphlet form or via a smartphone app.