Is wheat, fructans or gluten the problem?

Posted by Marnie Nitschke on

Expert food intolerance dietitian Marnie Nitschke explains why gluten may or may not be the problem. 

Wonderful wheat –  we’ve been cultivating this crop for tens of thousands of years, and for good reason! It’s versatile, delicious and an important, affordable source of energy and nutrients in traditional eating patterns. By grinding the grain and turning it into flour, we’re able to transform this humble grain into all manner of everyday staples, from whole-grain breakfast cereals and breads to pastry and cakes. 

Wheat is also used extensively as an ingredient in processed foods to enhance flavour and texture. So it’s pretty hard to avoid! And unfortunately, not all of us tolerate wheat particularly well due to a variety of factors.  

How would you know if you don’t tolerate wheat? You might feel excessively heavy and bloated after high-wheat foods like pasta, bread or pizza. It might give you stomach pain, diarrhoea, uncomfortable gas, reflux or constipation. For people who are wheat intolerant, wheat can even cause tiredness, aches, pains and brain fog.

So what is it about wheat that upsets some people, and how strictly do they need to avoid it? The answer is complicated (as it often is with nutrition). Let’s break it down:

A word about gluten.

Gluten is a unique protein found in the wheat grain and, consequently in wheat flour and products. It’s stretchy and great at binding moisture, which is key when we think of baked items like soft, doughy bread and light, delicate pastry. It’s also why gluten-free bread and pastry tend to be smaller, more dense, crumbly and dry. 

While gluten is a magical component when it comes to taste and texture, it’s also one of the likely culprits when someone reacts badly to eating wheat. This is because gluten is a complex molecule, which our digestive enzymes find hard to fully break down and absorb.  

For most of us, gluten can be consumed without any gut damage or adverse symptoms. But in some people with more sensitive digestive and immune systems, the ‘heaviness’ of gluten just doesn’t sit well and may even cause low-grade gut inflammation. Although studies are hard to come by, it has been estimated that approximately 5% of the population experience gluten sensitivity.

Importantly, gluten is the cause of intestinal inflammation seen with coeliac disease. 

What is coeliac disease?

Coeliac disease is a common autoimmune condition affecting about 1 in 70 Australians. It is caused by an underlying genetic trait that causes inflammation in the small intestine when gluten is consumed. In the case of coeliac disease, even very small doses of gluten (from cross-contamination or crumbs) can be enough to cause ongoing damage. As a result, adherence to a gluten-free diet needs to be strict and lifelong. 

Symptoms of coeliac disease can vary widely – from vague, irritable bowel-type symptoms through to nutrient deficiencies, diarrhoea, pain and weight loss. Surprisingly, how sick you feel does not correspond to the degree of bowel damage. Some may have severe symptoms but minor damage, while others may be symptom-free but have extensive damage.

If you have any gastrointestinal symptoms, unexplained nutrient deficiencies, or other autoimmune diseases, testing for coeliac disease and proper management is very important.  

Good to know:

To be tested for coeliac disease, you can have a simple blood test that looks for antibodies in your blood. It’s important to have this test while you’re still eating gluten for an accurate result. So please don’t try to self-diagnose and remove wheat before talking to your doctor or gastroenterologist. 

Fructans in wheat.

In the last 20 years, research into IBS and food intolerance has come leaps and bounds. We’ve learnt about particular carbohydrates in wheat - called fructans - that are big drivers of symptoms in sensitive individuals. 

Fructans are difficult to digest, highly fermentable sugars found separately to the gluten, in grains like wheat, rye and barley. These sugars are big gas producers and can draw water into the intestine, causing stretching of the gut, discomfort, diarrhoea, and constipation. Importantly, fructans do not cause damage to the gut.

Numerous studies have now shown that reducing wheat products, or opting for lower-fructan options like sourdough bread, or specially produced wheat flour can significantly reduce IBS symptoms. And this is without having to cut wheat or gluten out completely! 

What does this mean for me?

Proper testing and dietary advice is vital when dealing with wheat intolerance. Even if you have minor symptoms, or symptoms that come and go, testing for coeliac disease is the first step – before you remove wheat and gluten from your diet.

Many people with non-coeliac wheat or gluten sensitivity will tolerate some wheat products in their diet, and the amount tolerated will vary greatly. Frequent anecdotal reports describe breads, pasta and pastry being eaten and enjoyed during travel in Europe, while the same foods at home are not tolerated. This could potentially be due to nutritional differences in strains of wheat used around the world.

Once coeliac disease has been ruled out, experimenting with different foods is a good idea to find your threshold. This is best done with the help of an experienced dietitian who can guide you through a structured reintroduction process. 

At the end of the day, the more relaxed you can be with your diet, and the greater the variety of foods included, the better. A good croissant is a work of art that I wouldn’t want anyone to miss out on – unless it’s absolutely necessary!


Marnie Nitschke is an experienced Accredited Practising Dietitian who specialises in gastrointestinal nutrition and supporting people to have an easier relationship with food. Find out more at and follow her on Instagram @forkthatnutrition

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