Celiac disease and gluten-free eating: a calm, practical guide

The celiac disease diet is a strict, lifelong gluten-free way of eating. That means avoiding wheat, barley, rye and anything made from them, choosing naturally gluten-free foods and products labeled gluten-free, and keeping gluten from reaching your food through shared surfaces, pots and fryers. According to the NIDDK, a registered dietitian can help you learn to spot gluten when shopping, cooking and eating out.

Celiac disease is a long-term immune and digestive condition. When someone with celiac disease eats gluten, it triggers damage to the small intestine, which can cause ongoing digestive symptoms and reduce how well the body absorbs nutrients. The NIDDK estimates that about 1% of people worldwide have celiac disease, and that many people in the US who have it have not been diagnosed (NIDDK).

This guide covers the practical side: testing, grains, oats, labels and your own kitchen. It is general information, not medical advice. Your doctor and a dietitian who knows celiac disease are the right people to tailor it to you.

If you suspect celiac disease, the most useful thing you can do is keep eating gluten until you have been tested. The NIDDK explains that if you avoid gluten ahead of testing, the results may not be accurate (NIDDK).

• Blood tests look for certain antibodies that are usually higher than normal in people with untreated celiac disease.
• A small intestine biopsy, taken during an upper GI endoscopy, lets a pathologist look for the changes celiac disease causes.
• The Celiac Disease Foundation notes that you must be eating gluten for antibody testing to be accurate.

If you have already cut out gluten, talk to your doctor. They may suggest a supervised "gluten challenge", where you eat gluten again for a period so testing can work. The Celiac Disease Foundation says this should only be supervised by a physician trained in celiac disease, and never undertaken during pregnancy.

Gluten occurs naturally in wheat (including durum, emmer, semolina and spelt), barley, rye and triticale (NIDDK). Barley often hides as malt, malt extract, malt vinegar and brewer’s yeast. The Celiac Disease Foundation adds farro, farina, graham, einkorn and Kamut khorasan wheat to the wheat family.

The right-hand column comes from Coeliac UK’s grains guide, which also gives an important warning: naturally gluten-free flours can be milled where wheat flour is milled. Choose flours and grains labeled gluten-free where you can.

Beyond grains, gluten turns up in places you might not expect: sauces thickened with flour, traditional soy sauce, seasonings, soups and processed meats. Our guide to hidden sources of gluten walks through the most common ones.

Often, yes, with two cautions. The NIDDK says research suggests most people with celiac disease can eat moderate amounts of oats, but advises eating only oats labeled gluten-free, because cross-contact between oats and gluten grains is common (NIDDK).

• Contamination: regular oats are often grown and processed alongside wheat, barley and rye. Words like "pure oats" or "100% oats" do not mean gluten-free (Coeliac UK).
• Avenin: oats contain avenin, a protein similar to gluten. Coeliac UK notes that a very small number of people with celiac disease may still react to gluten-free oat products.
• Amount: the NIDDK suggests asking your doctor or dietitian how much oat is appropriate for you.

In the US, foods labeled gluten-free must contain less than 20 parts per million of gluten (NIDDK). The FDA explains that it chose this level partly because methods to reliably detect gluten below it were not yet validated when the rule was written.

• The claim is voluntary. A food can be gluten-free without saying so on the pack.
• A gluten-free food cannot contain wheat, barley, rye or crossbreeds such as triticale, or ingredients made from them, unless that ingredient has been processed to remove gluten and the food stays under 20 ppm.
• Malt extract, malt syrup and malt vinegar made from barley cannot be used in foods labeled gluten-free.
• The rule does not cover USDA-regulated meat, poultry and some egg products, or most alcoholic drinks (NIDDK).

Wheat is one of the nine major food allergens in the US, so it must be named on packaged food labels. Barley and rye are not on that list. That is why reading the full ingredient list matters, not just the "Contains" line. For the details of labels, certification and "made in a facility" statements, see gluten-free vs celiac-safe.

Cross-contact happens when gluten-free food touches gluten-containing food or surfaces. It can happen while food is grown, processed, stored, prepared or served, and the NIDDK recommends storing and preparing gluten-free foods separately at home.

A small, preliminary study shared by the Celiac Disease Foundation offers useful perspective. Gluten-free bread toasted in a shared toaster, and a knife used for both kinds of cupcake, mostly stayed under 20 ppm. Gluten-free pasta cooked in water already used for regular pasta did not: it picked up significant gluten, sometimes up to 115 ppm. Rinsing with fresh water reduced that. The researchers still recommend following your celiac care team’s guidance while more research is done.

1. Cook gluten-free pasta in a fresh pot of fresh water, every time.
2. Keep separate jars of butter, jam and spreads, or always use a fresh knife, so crumbs don’t travel (Coeliac UK).
3. Use toaster bags or a separate toaster, and consider a separate bread board.
4. Fry gluten-free food in fresh oil or a separate fryer.
5. Wash surfaces and cookware with hot soapy water or a dishwasher. Coeliac UK notes that standard washing removes gluten.
6. Store gluten-free foods on their own shelf, labeled, so everyone in the house knows.

If someone you live with eats gluten, our guide to caring for someone with food restrictions has ideas for shared kitchens.

Going gluten-free can feel like losing a lot of foods at once. It often helps to start from what you can build meals around rather than what you are leaving out. All of the ideas below rely on plain, naturally gluten-free foods, with the usual caveat: anything processed, marinated, seasoned or sauced needs a label check.

Gluten-free breads, pastas and crackers can be useful, but they don’t need to be the center of every meal. Rice, potatoes, corn, quinoa, buckwheat and millet are all naturally gluten-free starting points (Coeliac UK). Plain tofu is gluten-free, but marinated tofu often contains soy sauce, so check it.

If you live with IBS as well as celiac disease, some naturally gluten-free foods may still be among your triggers. Our IBS and low-FODMAP eating guide explains why, and a dietitian can help you combine both.

Gluten-free eating can be varied and nourishing. Plenty of everyday foods are naturally free of gluten in their plain form: fruit, vegetables, plain meat, fish, eggs, plain dairy, beans, lentils, nuts and the grains above. Processed, marinated or sauced versions are where you need to check.

The NIDDK notes that packaged gluten-free foods can be higher in sugar than the regular versions, and that your doctor or dietitian can help you plan gluten-free meals that meet your nutrient needs. It is worth asking them about fiber, iron and other nutrients, especially in the first months.

• Ask your doctor for a referral to a registered dietitian who knows celiac disease.
• Bring any new or changing symptoms back to your care team rather than troubleshooting alone.
• Keep a simple food and symptom diary if it helps those conversations.
• When you start eating out with celiac disease, plan ahead and ask specific questions.