Gluten-free diet

Gluten is a protein found in wheat, rye, barley, and oats. In people with celiac disease, eating or drinking anything containing gluten causes symptoms and damage to the lining of the small bowel. A gluten-free diet allows the bowel to heal and symptoms to improve.

Gluten is often blamed for the gut symptoms experienced by people with irritable bowel syndrome (IBS). However, recent research suggests that the carbohydrate component of wheat, rye, and barley (part of a group of foods known as FODMAPs) is more likely to be the cause of the problem for people with IBS.

Despite the restrictions, a person on a gluten-free diet can still enjoy a wide and varied diet. It is important to read the labels of all packaged or prepared foods.

Gluten-free foods#

Many foods are naturally gluten free, including:

• meat, fish, and chicken that is unprocessed (or frozen or canned with no sauce)
• eggs
• dairy products such as milk, yoghurt, most cheeses, cream, and many custards and ice creams
• fruits and vegetables – fresh, frozen, or canned (but not sauced), and fruit and vegetable juices
• seeds, nuts, and nut butters
• baking products such as corn (maize) flour, soya flour, lentil flour, rice and rice flour, potato flour, sorghum, buckwheat, millet, and amaranth
• naturally gluten-free grains and cereals such as rice, polenta, quinoa, buckwheat, tapioca, sago, arrowroot, and teff
• condiments such as tahini, honey, maple syrup, cocoa, most vinegars (except malt vinegar), tomato paste, and some sauces and dressings
• drinks such as water, milk, fruit and vegetable juices, coffee, mineral water, wine, and spirits

You can also buy commercially prepared gluten-free products, including bread, pasta and noodles, breakfast cereals, baking mixes, biscuits, crackers, condiments, and snack bars. Always check the labels, because some products may contain gluten where you would not expect it.

Foods that can contain gluten#

Always check labels carefully, as gluten can be found in products you might think are safe. Foods that can contain gluten include:

• cereals and baking products – wheat, wheat flour, spelt, semolina, couscous, wheat bran, barley, and oats
• breakfast cereals containing wheat, oats, or barley, and corn or rice cereals that also contain malt extract from barley
• some icing sugar mixtures and baking powders
• pasta and noodles such as spaghetti, lasagne, gnocchi, and many instant noodles
• bread, cakes, pastry, and biscuits made with gluten-containing flours (including spelt and sourdough)
• meat products prepared with breadcrumbs or batter, and many processed meats unless labeled gluten free
• thickened soups, meat pies, and frozen meals
• condiments such as malt vinegar, some mustards, relishes, pickles, dressings, stock, gravy, and yeast extract from barley
• snacks such as liquorice, some sweets and chocolates, savoury snacks, and some flavored chips
• drinks such as cereal-based coffee substitutes, some malted milk and drinking chocolate powders, and most beers (though gluten-free beers are increasingly available)

Reading food labels#

All packaged foods carry an ingredient label on the box, package, or bottle. There are a few ways to find suitable foods by reading the label, including looking for foods made for the general market that do not contain ingredients derived from gluten-containing grains.

In many countries, food labeling rules require ingredients and food additives derived from wheat, rye, barley, or oats to be declared, and gluten to be flagged when present. In many places, a product can be labeled “gluten free” if it contains fewer than 20 parts per million of gluten. Current tests can measure the gluten proteins in wheat (gliadin), barley (hordein), and rye (secalin), and a separate test for oats (avenin) is also available.

A note on oats#

Whether oats can be labeled “gluten free” varies between regions. In some places, oats may be marketed as gluten free if there is no measurable contamination with wheat, rye, or barley, so you may find products labeled “gluten free” that contain oats.

Evidence shows that uncontaminated oats are well tolerated by most people with celiac disease. However, in some people, eating oats can trigger a potentially harmful immune response. The absence of symptoms when eating oats does not necessarily mean they are safe, as bowel damage can still occur without symptoms.

It is recommended that anyone who wishes to include oats in their gluten-free diet does so under medical supervision. A gastroscopy and small bowel biopsy before and after three months of regular uncontaminated oat consumption can help guide whether a person with celiac disease can safely eat oats.

Gluten-free cooking#

A dietitian can recommend gluten-free recipe books, websites, and apps. As a general rule, choose recently published cookbooks, as older publications may contain outdated dietary information.

In some cases you can adapt existing recipes for cakes and biscuits to make them gluten free. Because gluten helps a cooked product hold together, you may need another binding agent. Suggestions include:

• replacing the role of gluten with xanthan gum or guar gum powder
• using gelatine or psyllium husk
• adding an extra egg to pancake batter

Be prepared to experiment, and accept that some early attempts may not work out. There are many recipes for gluten-free flour substitutes, or you can buy ready-made gluten-free flour mixes, pastry, and baking powder.

Avoiding gluten contamination#

To maintain a gluten-free diet, it is important for people with celiac disease to avoid contaminating their own food with gluten. Tips include:

• using a separate toaster for gluten-free bread, or protecting it in toaster bags
• cleaning all kitchen utensils, chopping boards, and appliances that have been used for gluten-containing foods
• preventing gluten-containing crumbs in condiments by having a single-dip policy, or keeping separate “gluten free” spread containers
• using a clean pot, clean water, and a clean strainer to cook gluten-free pasta
• using clean oil when deep frying
• washing your hands after handling gluten-containing food

Travel and a gluten-free diet#

Traveling on a gluten-free diet can present some extra challenges, but a little planning ahead goes a long way.

• Most airlines offer gluten-free meal options. Call the airline or use the online booking page to enter dietary requirements, and follow up a few days before you travel. Cruise lines can often accommodate gluten-free requests too.
• Always pack some gluten-free snacks in your hand luggage, such as rice crackers, nuts, dried fruit, and crisps.
• When booking accommodation, consider apartments with a kitchen, or at least a room with a microwave and refrigerator, so you can buy naturally gluten-free foods and self-cater.
• Use an app or website to find nearby restaurants with gluten-free options and shops that stock gluten-free foods.
• Restaurant cards in different languages can help you communicate your dietary needs when language is a barrier. The level of detail varies, so check the card in your own language to confirm it covers what you can eat, what to avoid, and cross-contamination.
• Some travel agencies specialize in organizing gluten-free friendly holidays.

Key points#

• Gluten is commonly blamed for gut symptoms experienced by people with irritable bowel syndrome (IBS).
• A gluten-free diet allows bowel healing and symptom improvement in people with celiac disease.
• It is important to read the labels of all packaged or prepared foods.
• Prevent gluten-containing crumbs in condiments by having a single-dip policy.

Where to get help#