Gluten – the good and the bad
What actually is gluten, and why does it cause some people problems? Professor David Cameron-Smith dishes up the facts.
Less than two decades ago gluten was the success story of the grains industry, with wheat varieties rich in gluten all the rage. This exciting, new-world wheat enabled the creation of deliciously fluffy, light breads and pastries, plus that perfect al-dente pasta.
Locked in with the starch from wheat, which is ground to make flour, is the small amount of gluten protein. Gluten is found in most grains and cereals, with the highest levels in wheat flour. When water is added to flour, it is the gluten proteins that give dough its elasticity and stickiness. Kneading bread flour separates the gluten proteins into long strands. When yeast is added, carbon dioxide bubbles are produced and trapped by the sticky and stretchy gluten. It’s these trapped bubbles that gives baked bread the soft, fluffy structure loved by so many. Without gluten, bread is flat, hard and often unappealing.
"Coeliac disease is an extremely severe bowel inflammatory response caused by an allergy to parts of the gluten proteins."
So what is wrong with gluten?
In the past few decades the rise in high gluten wheat has paralleled the emergence of coeliac disease as a major cause of ill health. Coeliac disease is an extremely severe bowel inflammatory response caused by an allergy to parts of the gluten proteins. The impact on the gut is severe, with significant damage to the delicate lining that aids in normal gut function. The current and only effective solution is a gluten free diet. For people with coeliac disease, this means exceptional vigilance. Gluten is found in trace amounts in many foods. Even gluten free alternatives, such as oats, can become contaminated in the production process. Gluten can be hidden in flavourings, modified food starches and is used as a binding agent in some supplements and vitamins.
Coeliac disease has a wide range of complications and symptoms from abdominal pain, diarrhoea, bowel irritability, iron deficiency anaemia and increased risk of osteoporosis. These symptoms also occur in many people who do not show the small allergic signs of coeliac disease. This is covered by the poorly described Irritable Bowel Syndrome (IBS). IBS is a syndrome because the causes are not yet known. The condition or conditions are real and often extremely debilitating, it’s just that there is little evidence that gluten intolerance is the root cause. This could be that the current tests for gluten allergy are not sensitive enough or not measuring the right immune target. Other theories are that it is not just gluten, but that the human gut can develop sensitivity and intolerances to a wide variety of ingredients, including some sugars (including frucans and oligosaccharides) and a range of plant proteins. Still other scientists are investigating whether the cause stems from the types of bacteria living inside the large intestine.
• Gluten: A protein found in wheat, rye, barley and oats and foods made from these grains.
• Coeliac disease: An autoimmune disease whereby consuming gluten causes inflammation and damage to the small intestine lining.
• Gluten sensitivity: A condition where eating gluten results in gastrointestinal symptoms similar to those in coeliac disease, without damaging the small intestine.