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Celiac disease vs non-celiac gluten sensitivity (NCGS), what’s the difference? For most people, foods containing wheat are a source of enjoyment, and, when chosen wisely, a key source of essential nutrients such as fibre. But for those who have one of a handful of digestive conditions, eating the staple grain can cause uncomfortable and even dangerous symptoms, not to mention serious long-term health problems.
Two of these disorder – celiac disease and non-celiac gluten sensitivity —seem to start in the digestive system, although they can affect other parts of the body, too. And they’re thought to be triggered by the same substance: gluten. (A protein found in wheat, barley, rye, and other variants – gluten is what gives bread dough its chewy, stretchy texture.) Because both conditions can cause symptoms similar to those of irritable bowel disease (IBS), diagnosing them can be tricky.
When someone with celiac disease eats food containing gluten, their immune system attacks finger-like structures called villi, which line the small intestine. (This type of ‘friendly fire’ makes celiac an autoimmune disease.) This abnormal response to gluten is not an allergic reaction, and celiac is not an allergy to gluten or wheat: allergies involve a different branch of the immune system.
Over time, these immune attacks can ‘flatten’ the villi—think of a field of grass after a hailstorm. Healthy villi—which greatly increase the surface area of the intestinal lining—are responsible for absorbing nutrients into the bloodstream. Consequently, celiac disease can lead to deficiencies in a wide range of vitamins and minerals.
While we don’t yet understand how the body responds abnormally to gluten in non-celiac gluten sensitivity (NCGS), there is some evidence that the immune system may be involved here, too. (1)
That said, it’s also possible that neither the immune system nor even gluten itself is always the culprit behind NCGS symptoms. In most studies looking at NCGS, participants are given gluten-containing grains rather than pure gluten. That means these people could be reacting to another component in wheat, barley, and rye. (2)
The prime suspect? A family of carbohydrates called FODMAPs. When not properly broken down, these carbs can be fermented by gut bacteria, leading to problems like abdominal pain. So it may be that some people with NCGS symptoms just don’t digest FODMAPs very well. (3)
One thing we do know for certain about NCGS? It doesn’t harm the villi. (4)
Only people who inherit either one or two specific genes can develop celiac disease. (5) But while these two genes are very common, only a tiny percentage of people who have them eventually get celiac disease. Why? Celiac disease is probably caused by a combination of genetics and other factors, such as exposure to certain viruses, pesticides, or other chemicals.
Still, celiac is one of the most common genetic diseases, affecting approximately one person in 100. (6) You may have an increased risk of developing celiac if you have a family history of the disease, or if you, or members of your family, have other autoimmune disorders.
When it comes to NCGS, it’s harder to say how many people are affected, in part because it hasn’t been studied as extensively. What’s more, some estimates are based on the number of people who’ve been diagnosed by a medical professional, but how many report avoiding gluten for any reason. (And that includes the popular, but mistaken notion that eating gluten is somehow unhealthy for people who don’t have celiac or NCGS.) With all that in mind, according to research conducted in Western countries, the prevalence could be as low as 0.6 percent, and as high as 10.6 percent. (7)
Because some symptoms of celiac disease and NGCS overlap, health care providers can’t distinguish between them based on symptoms alone. (It’s worth noting that if you have either celiac or NCGS, you may have one or more symptoms.)
A simple blood test can determine whether it’s highly probable that you have celiac disease, or not. Your immune system creates proteins called antibodies when it perceives a ‘threat’, such as a virus. Antibodies are tailored to ‘fit’ and ‘stick to’ a specific ‘invader’. Because their immune systems have mistakenly labelled gluten as an ‘enemy’, people with celiac disease have high levels of certain antibodies in their blood.
However, antibody testing is just the first step in diagnosing celiac disease. The definitive test is an endoscopic biopsy. (11) During this procedure (which is typically done under sedation), a fine tube is passed from your throat down into your small intestine. A tiny camera on the end of the tube allows the gastroenterologist to examine the interior of the intestine. Another small tool attached to the tube is used to take a small sample of the intestinal lining. Afterward, a pathologist will examine the biopsied tissue to check for signs of damage and inflammation.
One thing that’s important to know about both of these tests: the results will only be accurate if you are still regularly eating gluten-containing foods.
Unfortunately, NCGS is what’s called a diagnosis of exclusion. That means your health care team has to rule out other conditions with similar symptoms before concluding you have NCGS. This includes getting a negative result on an antibody test for celiac.
Currently, the best—and only—treatment for celiac disease is a strict gluten-free diet. But while very effective, it’s not a cure—it only works as long as you stay on it.
The good news is continuing to avoid gluten doesn’t just improve your symptoms: it gives your small intestine a chance to heal and regrow villi. This repair process can take anywhere from three months to two years to complete, depending on factors like age. (12) Something else to keep in mind: small amounts of gluten can cause damage without necessarily causing symptoms.
If you have NCGS, your symptoms should improve when you follow a gluten-free diet, too.
There are two things you should do first—don’t just go ahead and jump in on your own. Number one, wait until you’re officially diagnosed with celiac or NCGS. (And remember—if you’re on a gluten-free diet before getting tests that help make that diagnosis, the results won’t be accurate.)
Next, get help from a registered dietitian who has expertise in these conditions.
Why? For starters, when you cut healthy grains from your diet, it can be difficult to ensure that you’re getting an adequate supply of the nutrients they contain from other sources. And while there’s never been a better selection of prepared gluten-free foods to choose from, most are much lower in vitamins, minerals, and nutrients than their gluten-containing counterparts. (13) Gut health dietitians can often recommend recipes that suit your tastes, too, or suggest ways of making a gluten-free version of a favourite dish.
Then there’s the fact that gluten is hidden in all kinds of foods that you wouldn’t suspect, from soya sauce and spice mixes to salad dressing, processed meats, bouillon cubes, and even some medications and supplements. Knowing what to look for on food labels is a skill that takes time to learn, and it will be easier if you get expert help.
With a little guidance, you should still be able to eat a delicious diet that will keep your symptoms at bay, and protect your long-term health.