A gluten free diet is followed by individuals with coeliac disease, dermatitis herpetiformis or non-coeliac gluten intolerance. Gluten is a protein made up of glutelin and prolamin. Wheat, rye, barley and oats and most ingredients derived from these grains must be avoided.
What and Where Is Gluten?
Gluten is the main protein in wheat, rye, oats, barley and other similar grains and their products including wheat family: atta, bourghul/bulgar/bulghur/bulgar, couscous, dinkel, durum, emmer, farina, faro, freekah, German wheat, graham flour, kamat, Polish wheat, semolina, spelt, triticale (hybrid of wheat and rye) as well as malt (barley), pilcorn (oats). Gluten contains an equal amount of two protein fractions glutelin and prolamin. It is the latter, alcohol soluble prolamin that is thought to cause damage in coeliac disease.
Oats contain 5-15% of the damaging prolamins, and are still recommended to be excluded by people requiring a gluten free diet. There is current research investigating the possibility that some people with coeliac disease may be able to tolerate oats in their diets. The inclusion of oats in gluten-free diets is also controversial not only because of uncertainty whether they cause mucosal damage in coeliac disease, but also because oats are commonly contaminated by contact with wheat or barley during harvesting, transport, storage or milling.
Different prolamins are also found in rice, corn/maize, millet and sorghum; however, these prolamins do not have the same damaging effects and can be consumed safely. More research is needed to further understand the mechanisms involved.
Gluten-containing Food and Understanding Food Labels
Gluten is found in foods containing wheat of all types, rye, oats, barley and triticale, all of which need to be avoided in a gluten free diet. As gluten has rubbery, elastic characteristics, it is often used as an ingredient in bread, cakes, pasta and many other types of prepared and commercial foods.
Gluten can also be found in foods that contain ingredients that are derived from the gluten-containing grains listed above, including bran, couscous, flour, semolina, spelt and wheat germ, as well as wheaten corn flour, malt, malt extract, malt vinegar and starch derived from wheat.
For this reason it is not always apparent which foods contain gluten. Examples of less apparent sources of gluten include confectionery, sauces, gravies, soups, sausages or processed meats, starch, hydrolysed vegetable protein (HVP), natural flavouring, soy sauce, and even beer and some medications. It is surprising where you can find it! Food labels must always declare sources of gluten.
Coeliac New Zealand has a useful website at www.coeliac.org.nz and a help line 09 820 5157.
Sources Of Gluten
To assist people with food allergies who need to avoid gluten, Food Standards Australia New Zealand (FSANZ) requires that ingredients derived from cereals containing gluten and their products, namely, wheat, rye, barley, oats and spelt and their hybridised strains must always be declared on food labels (other than beer and spirits). This requirement is part of the food standard relating to Mandatory Declaration of certain substances in Food Likely to Cause Adverse Reactions (including gluten). Reading the ingredient lists on products is extremely important! Where food is offered without its label e.g. restaurants, canteens, buffets, for immediate consumption, the allergen information must be declared in connection with the display of the food, or declared to the purchaser upon request.
Food labelled as ‘low gluten’ must contain less that 0.02% gluten (or 20 mg gluten per 100g food), and no oats or malt. There is no place for foods with a ‘low gluten’ claim on label in the coeliac diet. Some people with other forms of gluten intolerance may find these foods useful.
Example Ingredient List:
Barley: Ingredients derived from gluten-containing grains must be declared on food labels.
Gluten Free Food
The manufacture of gluten free products requires that stringent processing guidelines be followed. This is to ensure that gluten free raw material is not contaminated by gluten containing foods. According to the Food Standards Australia and New Zealand, food labelled as ‘gluten free’ must not contain any detectable gluten, and no oats or malt. Food labelled as ‘low gluten’ must contain less that 0.02% gluten.
Once familiar with label reading, following a gluten free diet will not be difficult to manage, but it is recommended to seek initial expert guidance from an Accredited Practicing Dietitian, who can give assistance with advice to suit individual needs.
Care must also be taken to replace wheat, rye, oats and barley with other cereals because these grains are a valuable source of carbohydrates, fibre, vitamins and minerals. Suitable grains and cereals include: arrowroot, amaranth, buckwheat, corn/maize, lupin, corn flour (maize), millet, polenta, potato flour, psyllium, rice, sago, seeds, sorghum, soy and tapioca.
Ingredients derived from gluten containing grains that have been highly processed to remove all protein are also suitable; examples include caramel colour, glucose (syrup and powder), maltose, fructose and dextrose. Food Standards Australia New Zealand require that any food which contains grains containing gluten or products made from grains containing gluten must have this information on the label. An example is dextrose which can be derived from many grains. The processing to produce dextrose removes all detectable gluten however a product containing dextrose derived from wheat must say ‘contains products from wheat’ or ‘wheat dextrose’. If this product is labelled ‘gluten free’ then the manufacturer has also independently analysed the product and found no detectable gluten.
Cooking Gluten Free
In cooking, gluten makes rising possible, stretching around trapped air and setting when cooked. It can be very difficult to replace gluten in cooking. For baking, a mixture of flours often works best. To make an acceptable substitute, ensure you substitute by weight and not by volume. Also, to make gluten free flours rise better, mix gluten free baking powder or soda with water before adding it to the dry ingredients.
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This fact sheet contains general information and is not intended as a substitute for medical advice. Please consult your healthcare professional for specific advice for your personal situation.
Food Standards Australia New Zealand (2011). The Australian New Zealand Food Standards Code Section 1.2.8. Anstat, ACT. www.foodstandards.gov.au/_srcfiles/Standard_1_2_8_Nutrition_Info_v115.pdf
Coeliac New Zealand www.coeliac.org.nz
What is Coeliac Disease – The Coeliac Society 2011. www.coeliacsociety.com.au/dis-what.html
Coeliac Disease web page last updated October 2010 from Health Insite A healthdirect Australia health information service this page has other useful links www.healthinsite.gov.au/topics/Coeliac_Disease
Coeliac Research Fund www.coeliacresearchfund.org/
Coeliac Disease Dietitians Association Australia web site Last Updated: Tuesday, 18 January 2011 http://www.daa.asn.au/index.asp?pageID=2145834411
The Gut Foundation (2005). Coeliac disease: food allergy & intolerance. The Gut Foundation: Randwick, NSW. www.gut.nsw.edu.au/assets/documents/Coeliac Text.pdf
Ciclitira, P.J., Ellis, H.J., Lundin, K.E.A. (2005). Gluten-free diet – what is toxic? Best Practice & Research Clinical Gastroenterology 19:359-371.
Better Health Channel (last updated Nov 2010) Gluten Free Alternatives www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Gluten-free_alternatives?open
Better Health Channel Gluten Free Diet (last updated Mar 2011) www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Gluten-free_diet?open