For many people, decisions about what to eat every day aren’t especially complicated. Some center simply on what they can find or afford on a given day. The more fortunate ponder what to put on pizza, which delivery service to use, or how to make the best use of a leftover moldering in the fridge.

Food choices are far more complicated for millions of others. For example, an estimated 32 million people, including 26 million adults, in the United States have at least one food allergy, with peanuts, tree nuts, milk and shellfish being the most common culprits.

About 1% of people in the United States – some 3 million – face another kind of food nemesis: grains that contain the protein gluten. Worldwide, the prevalence of the disease stands at 1.4%. The substance triggers an array of intestinal and other problems, which are not allergic reactions, but rather the result of celiac disease, a genetic autoimmune disorder that causes the body to attack itself. Those with celiac disease must rigorously avoid consuming foods containing gluten – no easy task, even after excluding obvious targets like bread and pasta.

People with celiac disease have no choice but to go gluten-free, while millions of others can happily butter their bread or ladle marinara sauce over their pasta. But gluten occupies a more complicated spot in our daily diet. For example, some who don’t have celiac disease have a sensitivity to gluten that they must manage. Still others have decided that for whatever reason they want to avoid gluten, not out of necessity but by choice.

To answer questions about celiac disease, gluten sensitivity and gluten avoidance, UCHealth Today spoke to Sarah Funk, a registered dietitian and Certified Nutrition Support Clinician with the UCHealth Digestive Health Center at UCHealth University of Colorado Hospital on the Anschutz Medical Campus.

What is gluten and what are some of the common places it shows up in our diet?

“Gluten is a protein found in wheat, barley and rye that is used to make flours and many other products,” Funk said. She noted that breads and pastas are obvious gluten-containing foods, but broth, bouillon, and many packaged items frequently contain it.

What is celiac disease?

First, it’s not a food allergy or sensitivity, Funk said. It’s a genetic, autoimmune disease. Simply put, gluten causes the immune system to react and attack the body, with the intestine being the primary battleground.

“When people with celiac disease ingest gluten, the protein causes chronic inflammation in the intestine,” Funk said. In turn, she explained, the inflammation damages the villi, which are finger-like tissue projections that line the small intestine. The villi are crucial in helping your body take in nutrients from food into your bloodstream.

“Flattened or damaged villi minimize the absorptive area of the small intestine,” Funk said. As the damage progresses, people with celiac disease get fewer of the nutrients they need to be healthy, she added.

What are the symptoms of celiac disease?

“Ongoing or intermittent symptoms” like gas, bloating, abdominal pain, diarrhea and sometimes constipation are clues, Funk said. Left untreated, celiac disease can also lead to weight loss, iron deficiency, anemia, osteoporosis, and an increased risk of lymphoma. Parents should keep an eye on their child’s growth rate, Funk added. If it falls significantly behind expectations, it’s a warning sign of celiac disease.

How is celiac disease diagnosed?

If symptoms raise a celiac disease red flag, providers screen patients for it with a blood test for particular antibodies triggered by gluten, Funk said. “If the blood test is positive, the provider would typically proceed with doing an upper endoscopy with a biopsy of the small intestine,” she said. This outpatient procedure allows providers to closely examine the lining of the intestine for evidence that confirms celiac disease, such as damage to the villi.

How is celiac disease treated?

People with celiac disease must commit to eliminating gluten from their diet – period. “There is no other medical management at this point,” Funk said. As a dietitian, however, she can help patients meet the challenge of changing and modifying their food choices.

“I first try to understand a patient’s diet patterns and preferences to identify where they are ingesting gluten,” Funk said. “How are we going to find good replacements for those foods and find areas for improvement?”

Funk said education is an important part of the work. That includes explaining what gluten is, where to find it in foods, how to read labels, how cross-contamination of foods can occur, how to prepare meals, and strategies to manage eating out.

“We are trying to equip patients with that knowledge, so they feel that being gluten-free is manageable and doable,” Funk said.

Do you have food-choice tips for people diagnosed with celiac disease?

It’s important, first of all, for people to view the diagnosis as a positive, Funk said, rather than dwell on the crackers, breaded food, pasta, and other favorite foods it will take away.

“I tell them, ‘Before your diagnosis you were eating gluten on a regular basis, and now you’re going to start feeling better,’” Funk said. “You’re going to be eating a diet that is healthier for your body.”

Funk said she also centers attention on what people can eat. “Focus on natural, basic foods that are always gluten-free.” Those include fruits, vegetables, meat, beans, and lentils, of course, but also plentiful gluten-free grains – amaranth, quinoa, rice, and flax, among others.

“This is how all of us should eat,” Funk said. “You can still have things you enjoy; you just have to pull out the gluten grain part.” There is plenty of help for that: gluten-free recipes abound.

Do you have advice on how to avoid unexpected exposure to gluten?

People with celiac disease must be diligent label readers, Funk said. For example, one might not expect a can of tomato soup to contain wheat, but manufacturers often use it as a thickener. Sometimes gluten lurks, cloaked in ambiguous terms. For example, “natural and artificial flavorings” may be code words for barley or wheat, she said. “Modified food starch” can be another unexpected troublemaker.

How to be sure? “Call the company to check,” Funk said. “If they don’t respond, avoid that food.”

Cross-contamination of foods is another potential risk. Some products state that they were made in facilities that process wheat or other grains, but the warning is voluntary, Funk said. Without it, people should exercise caution when they buy certain foods, such as oats, which are otherwise gluten-free and safe for all but a small fraction of people with celiac disease. “It’s very common that oats are processed on the same machinery as a wheat product,” Funk said.

Restaurant kitchens can also be sources of cross-contamination. Funk advised people to plan before going out. “You can call ahead to speak with the manager and ask, ‘What are your practices for [avoiding] cross-contamination?’” she said. For example, restaurants that do not have dedicated stovetops and fryers for gluten-free food can be a problem.

It’s hard to know with certainty the ingredients that restaurants use to prepare the dishes. Many places label menu items that are gluten-free, but Funk advised exercising caution if marinades or sauces are included, as they may hide gluten. The website findmeglutenfree is a Yelp-like site that allows diners to rate their restaurant experiences from a gluten-free perspective, she said.

Finally, even the words “gluten-free” may have different meanings from one product to the next. To be labeled “gluten-free,” a product must contain less than 20 parts per million, Funk said. However, some foods are “certified” gluten-free if they meet more stringent standards, including fewer parts per million and tighter manufacturing and inspection regulations. For example, the Gluten Free Certification Organization (GFCO) requires that foods receiving its gluten-free label have 10 parts per million or less.

Why the seeming hair-splitting on gluten? “Some people react to smaller amounts than others,” Funk said. “It’s important for all people with celiac disease to be as careful as possible and to find what is questionable for them.”

I’ve been told I’m gluten-intolerant or gluten-sensitive. What does that mean?

Non-celiac gluten sensitivity (NCGS) produces many of the same symptoms experienced by people with celiac disease, Funk said. Those with NCGS may feel better if they avoid gluten, but the blood test that screens for celiac disease produces “no clinical showing of being sensitive to gluten,” Funk said.

An individual’s NCGS symptoms may be a response to fermentable carbohydrates, or FODMAPs, found in beans, garlic, onions, and other foods, including some other fruits and vegetables and, yes, wheat, Funk said.

“It could be that the body is fermenting those foods more than others, and that creates byproducts of gas” and other symptoms, she said. Because wheat contains fermentable carbohydrates, removing it from the diet may make people with NCGS feel better, Funk said.

However, she also noted that the symptoms of NCGS and celiac disease also overlap with other digestive problems, including irritable bowel syndrome and small intestinal bacterial overgrowth (SIBO). That underscores the importance of seeking help from specialists trained in digestive health.

“It’s important to have the correct diagnosis and then change your diet accordingly,” Funk said.

I don’t have celiac disease or NCGS, but I want to be gluten-free. Is that a problem?

No. However, wheat, barley, and rye do contain valuable nutrients, such as fiber, B vitamins (thiamine, riboflavin, niacin, and folic acid), and iron. “If you choose to avoid these grains, it’s important to replace these nutrients from other food sources,” Funk said.

“You can always make the decision to be gluten-free,” she added. “It’s your body, and it’s your choice. We inform our patients how to eat a balanced and nutrient-dense diet based on any needed or preferred restrictions.”