Gluten is a mixture of two proteins, gliadin and glutenin. When mixed with water, it becomes sticky and so forms the familiar texture of dough made from wheat and rye flour. When gluten comes into contact with the lining of the small intestine, a reaction occurs, where the immune system mistakenly attacks the lining of the bowel as if it was a ‘foreign’ organism.
The small intestine has ‘villi’, which are tiny finger-like projections, visible under the microscope. They provide a large surface area, over which we absorb nutrients, such as vitamins, folic acid, iron and calcium. In coeliac disease these villi are attacked by the immune system and are eventually destroyed. This results in food going down the gut without nutrients being absorbed (malabsorption), leading to vitamin and mineral deficiencies, anemia, and osteoporosis.
Gluten is found in wheat, barley, and rye. That means a gluten-free diet cannot include bread, biscuits, cakes and pastries, pasta, common breakfast cereals, and many manufactured soups and sauces. Gluten is also hidden in some foods such as chips and similar snacks, as well as chips in restaurants. Stay away from “modified food starch” too.
Cooking oil (or mixed vegetable oil) can contain wheat-germ oil, so use sunflower or olive oil instead. Malt vinegar, soy sauce, mustard and mayonnaise contain gluten. Beer and whisky are made from grain containing gluten, but other alcoholic drinks, such as wine or cider are gluten-free. Most specialists now consider all distilled forms of alcohol safe to drink, provided no colorings or other additives have been added, as they might include gluten ingredients. Wine, sherry, port, cider, rum, tequila, bourbon and vermouth are all probably safe. Liqueurs and pre-mixed drinks should be examined carefully for gluten-derived ingredients.
Special care must be taken when checking ingredients lists as gluten may come in forms such as vegetable proteins and starch, modified food starch (when derived from wheat instead of maize), maltodextrin, malt flavoring, and glucose syrup. Many common ingredients contain wheat or barley derivatives.
Some medicines contain gluten, so you must check with your pharmacist.
The suitability of oats in the gluten-free diet is still somewhat controversial. Some research suggests that oats in themselves are gluten free, but that they are virtually always contaminated by other grains during distribution or processing (most oats are milled and stored in the same mills as wheat and are probably contaminated with gluten). However, recent research indicated that a protein naturally found in oats (avenin) possessed peptide sequences closely resembling wheat gluten and caused mucosal inflammation in significant numbers of coeliac disease sufferers. Some examination results show that oats are very dangerous to certain celiacs, while not very harmful to others. Given such conflicting results, excluding oats is the only risk-free choice for coeliac disease sufferers.
Hidden Gluten
Here’s a list of places you might not expect to find gluten:
- Sausages contain breadcrumbs (the bread is one of the ways in which the texture of the sausage is obtained, without including an unacceptably high proportion of fat), except the most high class variety of butcher’s sausage, and even in this case it’s quite likely.
- Burgers, grillsteaks and similar products generally also include bread or other wheat products in the mixture.
- Crab sticks and prawnies seem to be made entirely of fish, but if you check the label and you will find wheat flour or modified starch listed in the ingredients.
- Some drinks contain gluten as a thickener, to provide ‘body’.
- Wheat flour may be a hidden ingredient in ice cream, ketchup, mayonnaise and instant coffee.
- You often find gluten in low fat versions of products, to make them seem less watery (for example, yoghurt, soft cheese or mayonnaise).
- Pre-packed grated cheese is coated in flour or modified starch to stop it from sticking together in the packet – this includes the cheese sold with jacket potatoes in takeaways, unless they grate their own (but most don’t).
- Obviously, anything coated in batter or breadcrumbs contains gluten in the coating. This makes almost every fish product out of bounds for the gluten intolerant, as the ones that aren’t coated are usually packaged in a sauce thickened with flour.
- Monosodium glutamate, known to Chinese cooks as ‘taste powder’ or ‘ve-tsin’ is manufactured with gluten. This ingredient is very frequently included in factory-prepared goods, but may not be listed on the label – or merely described as a ‘flavor enhancer’ or ‘natural flavoring’.
- Soy sauce is almost always made by fermenting soy beans and wheat together, so contains gluten.
- Although wheat germ does not itself contain gluten, because of the process of separation employed in manufacture, it is likely that a small amount of gluten will be present in wheat germ sold in the stores.
- Malt and malt extract are derived from wheat, and can be a hidden source of gluten. This is sometimes listed as maltase or malto-dextrin.
- Any alcoholic drink made from grain — beer or whisky, for example, contains gluten.
- Even medicines may contain gluten, used as a thickener or a binder.
Gluten-free food
Of course, many foods do not contain gluten, including all fruits and vegetables, rice, maize, sweet corn, nuts, potatoes, red meat, chicken, fish, eggs, and dairy products (although a lot of patients with gluten allergies also react poorly to dairy, so if a gluten-free diet does not improve your symptoms, we should look at a dairy-free diet too).
Several grains and starch sources are considered acceptable for a gluten-free diet. The most frequently used are maize (corn), potatoes, rice, and tapioca (derived from cassava). Other grains and starch sources generally considered suitable for gluten-free diets include amaranth, arrowroot, millet, montina, lupine, quinoa, sorghum (jowar), sweet potato, taro, teff, and yam. Various types of bean, soybean, and nut flours are sometimes used in gluten-free products to add protein and dietary fiber. In spite of its name, buckwheat is not related to wheat; pure buckwheat is considered acceptable for a gluten-free diet, although many commercial buckwheat products are actually mixtures of wheat and buckwheat flours, and thus not acceptable.
Important: This article is not intended to serve as a treatment for gluten allergy, nor is it intended as a substitute for qualified nutritional and medical guidance from appropriate professionals.