- Gluten Sensitivity (Intolerance) Center
- Take the Pancreatitis Quiz
- Boost Digestive Health
- Digestive Distress Slideshow: Problem Foods to Avoid
- Patient Comments: Gluten Intolerance - Symptoms
- Patient Comments: Gluten Intolerance - Experience
- Find a local Doctor in your town
- Gluten sensitivity (intolerance) definition
- What are gluten intolerance symptoms?
- What is the relationship between gluten intolerance and celiac disease?
- Is nonceliac gluten sensitivity real?
- What other diseases mimic celiac disease?
- Food allergies or food intolerance
- What are FODMAPs?
- What is bacterial overgrowth?
- What are functional intestinal disorders?
- Is there any evidence that nonceliac gluten sensitivity is really a disease or condition?
Gluten sensitivity (intolerance) definition
Gluten sensitivity is defined as a reduction in symptoms after eliminating gluten-containing products from the diet.
What are gluten intolerance symptoms?
Gluten sensitivity is all the rage these days. Not a week goes by that I don't see a patient with gastrointestinal symptoms who has started a gluten-free diet - or what they think is a gluten-free diet - who tells me that their symptoms have improved. They describe their symptoms as feeling bloated and gassy, experiencing abdominal pain, diarrhea, and abdominal cramping. Gluten-free products are flooding the market place. Most of these gluten-free products have always been gluten-free, but their gluten-free status now is being advertised for marketing purposes. What's going on here? Is gluten sensitivity really a new "disease?"
What is the relationship between gluten intolerance and celiac disease?
As with most things health-wise, the situation is complex. The first thing to understand is that the gluten sensitivity of celiac disease, a well established disease that affects less than 1% of the population in the U. S., is due to an autoimmune process. This can be considered as an allergic reaction to proteins contained in gluten typically found in several common grains, including wheat, rye and barley. Celiac disease is easily diagnosed by blood tests and intestinal biopsy. The only practical treatment for celiac disease is a strict, gluten-free diet. Ninety-nine percent of individuals I see who report gluten sensitivity, however, do not have celiac disease. So, why do they feel better on a gluten-free diet? There is likely to be more than one explanation.
Is nonceliac gluten sensitivity real?
I suspect that a common reason for self-diagnosing gluten sensitivity is the placebo effect. The placebo effect is much greater for subjective symptoms (such as those of patients with self-diagnosed gluten sensitivity) than is appreciated. It is seen in 20% to 40% individuals. That is, of patients who report an improvement in symptoms by eliminating gluten, 20% to 40% are NOT improved. They THINK they are improved. (Purists may argue that it doesn't matter if they really are improved as long as they think they are improved.) It also is possible that some of the placebo response is real and due to psychological reasons. For some patients, the placebo effect is enough, and they don't mind the dietary restrictions of a gluten-free diet. I don't see those patients in my practice.
Of the patients that I do see who report that their symptoms have improved on a gluten-free diet, almost all have had their symptoms return or continue with reduced severity despite continuing the diet. There are two potential explanations for recurrent or continuing problems; either the placebo effect is wearing off or something other than gluten sensitivity is going on in addition to gluten sensitivity. What else might be occurring?
What other diseases mimic celiac disease?
There are numerous gastrointestinal diseases that could be causing symptoms similar to celiac disease. The intestine has a limited repertoire of symptoms with which to respond to disease, so it is not surprising that symptoms of many intestinal diseases can mimic those of food intolerances like gluten sensitivity. That's why it is important for individuals to be evaluated by their physicians to exclude intestinal diseases even if they think the problem is food intolerance. A gluten-free diet not only reduces the intake of gluten, it also alters the intake of other nutrients. Therefore, it is possible that the alterations of these other nutrients and not the reduction in gluten affects the symptoms of other intestinal diseases, for example, inflammatory intestinal diseases such as inflammatory bowel disease.
Food allergies or food intolerance
The next question to address is could the symptoms be due to an allergy to foods in the diet other than gluten? Allergic reactions to foods are caused by the proteins they contain. Some of the most common and well-documented food allergies in adults are milk protein, eggs, soy, shellfish, and nuts, particularly peanuts. It is difficult to diagnose food allergy. The standard tests for allergy, including skin and blood tests, are not very precise. The only way to diagnose food allergy is by eliminating the potentially offending food from the diet and observing the response of symptoms. Unfortunately, this puts us back dealing with the placebo effect. Since food allergy is infrequent in adults, it probably is not the explanation for symptoms among patients, even those who think they have gluten sensitivity.
There are examples of food intolerances or sensitivities other than gluten. Probably the most common is milk intolerance, with symptoms arising because of the inability to digest lactose, the sugar in milk. The undigested, unabsorbed lactose reaches the colon where colonic bacteria turn it into gas and chemicals that cause symptoms. Most people who have improved with a gluten-free diet and believe they are gluten-sensitive already have tried eliminating milk and milk-containing foods from their diet. It didn't work. Could there be an intolerance to another food that causes the symptoms? What food could it be?
What are FODMAPs?
There is another dietary intolerance that can cause gastrointestinal symptoms, the inability to digest FODMAPs (fermentable oligo-, di-, and mono-saccharides and polyols). FODMAPs are sugars or sugar-related molecules that are found in fruits and vegetables. The most common example of a FODMAP is fructose, a common, plant-derived food-sweetener. FODMAPs in some individuals are poorly digested and absorbed. They pass through the small intestine and enter the colon where bacteria specific to the colon break them down into gas and other chemicals that can give rise to gastrointestinal symptoms, just like with the lactose in milk in individuals who are lactose intolerant. I am beginning to see an increasing number of patients with self-diagnosed FODMAP intolerance based on the response of reduction of symptoms to the elimination of FODMAPs from their diets. FODMAP intolerance probably is a real entity made more likely by recent changes in dietary patterns which include more fruits and vegetables AND dietary sweeteners. Of course, just as with gluten sensitivity, there is a likelihood of a placebo response to the elimination of dietary FODMAPs.
What is bacterial overgrowth?
Then there is another condition to consider, bacterial overgrowth of the small intestine, a condition in which the bacteria normally found only in the colon move up into the small intestine. Looked at simply, as the bacteria moves from the colon into the small intestine (where they don't normally reside), they are able to get to the food within the small intestine (in particular sugars and carbohydrates), before these can be fully digested and absorbed. They then produce gas and the other chemicals that they normally produce in the colon. As a result, the production of gas and chemicals is greater than normal. Since a gluten-free diet is low in carbohydrates, a gluten-free diet may also reduce symptoms caused by bacterial overgrowth simply because it contains fewer carbohydrates. Bacterial overgrowth clearly exists, but it is difficult to study and remains rather unclear as a cause of gastrointestinal symptoms including IBS. Theoretically, the symptoms of bacterial overgrowth could be aggravated by FODMAP intolerance. Moreover, FODMAP intolerance could be due entirely to bacterial overgrowth or to the presence of specific types of bacteria in the intestine.
What are functional intestinal disorders?
Finally, there are the "functional" intestinal disorders, disorders in which no anatomic, histological (microscopic) or biochemical cause for the gastrointestinal symptoms can be found, and the abnormalities are assumed to be functional, for example, due to abnormal function of the central nervous system (brain), gastrointestinal muscles and nerves, or intestinal secretions. Irritable bowel syndrome (IBS) is one of these functional disorders. IBS was at first defined broadly, but over the years its definition has become restricted such that it is now defined as abdominal pain associated with an alteration in bowel habit. Other non-IBS functional disorders have been defined, for example, the occurrence of abdominal discomfort after meals. Many patients who believe that they have gluten sensitivity have previously been diagnosed with a functional disorder such as IBS.
Is there any evidence that nonceliac gluten sensitivity is really a disease or condition?
You might think that it's easy to study scientifically the effects of dietary changes and determine what dietary factors are responsible for symptoms. It is not. It is very difficult and expensive to do rigorous studies of diet. Finally, after years of debating the existence of nonceliac gluten sensitivity, a scientifically rigorous study has been done that sheds light on the issue. In this study, 37 patients with self-reported gluten sensitivity, well controlled on a gluten-free diet were studied. They were given a baseline diet that was gluten-free and low in FODMAPs. After observing symptoms on this baseline diet, the patients were divided into two groups. In addition to the base diet, one group received relatively pure gluten and the other group a gluten placebo. Neither the group receiving gluten nor the group receiving placebo developed symptoms. In other words, the group of patients with self-reported gluten sensitivity were not gluten sensitive when tested.
Is this evidence for a placebo effect? Possibly. Could it be that FODMAPs in the patients' usual, unrestricted diets were causing their symptoms? Could the way in which they altered their usual diets to become gluten free have reduced as well the FODMAPs in their diet and thereby caused the improvement in symptoms they ascribed to gluten sensitivity? In fact, many foods high in gluten also are high in FODMAPs, so that a gluten free diet might be expected to be lower in FODMAPs. Are nonceliac, gluten sensitive individuals suffering from FODMAP sensitivity? It could be. The important message to take away from this study is that people with self-diagnosed gluten sensitivity are not gluten sensitive. It would be useful now to do a study demonstrating that it is the FODMAPs that are causing the symptoms in these patients.
Subscribe to MedicineNet's General Health Newsletter
Considering all of the information that is available, what is a practical approach to dietary intolerances, particularly suspected gluten sensitivity? First, true celiac disease and other important gastrointestinal diseases need to be excluded. There is nothing wrong, then, with a trial of a gluten-free diet. If symptoms respond adequately and the restricted diet is not a burden, the diet can be continued. There is also nothing wrong with then trying a low FODMAP diet. As with a gluten free diet, if the symptoms improve adequately and the diet is not a burden, it can be continued.
If the symptoms don't respond or the diet is too difficult to maintain, it is reasonable to consider bacterial overgrowth of the small intestine and test for it by breath testing. A fructose breath test (fructose is a FODMAP) has been proposed to identify patients with FODMAP intolerance, but we don't yet have a good idea of how effective this test is at identifying patients whose symptoms respond to reduced dietary FODMAPs. Nevertheless, the test may be worth doing, even if patients say that they have had no improvement on a low FODMAP diet. Since a low FODMAP diet is not easy to follow, patients may have inadequately reduced their intake of FODMAPs, and this may have prevented an improvement in symptoms.
Health Solutions From Our Sponsors
Biesiekierski, JR, Peters, SL, Newnham, ED, et al. No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates. Gastroenterology 2013;145:320-328.
Gluten Intolerance - Symptoms
What symptoms do you experience with gluten intolerance?Post View 10 Comments
Gluten Intolerance - Experience
Please describe your experience with gluten intolerance.Post View 6 Comments
Gluten Intolerance - Food Allergies or Intolerance
Please share your experience with food allergies or intolerance.Post
Gluten Intolerance - FODMAPs
Are you sensitive to FODMAPs?Post
Gluten Intolerance - Bacterial Overgrowth
Please share your experience with bacterial overgrowth.Post
Gluten Intolerance - Functional GI Disorders
Please describe your experience with IBS or other GI functional disorders.Post
Top Nonceliac Gluten Sensitivity (Intolerance) Related Articles
Abdominal Pain (Causes, Remedies, Treatment)Abdominal pain can have many causes that range from mild to severe. Some of these causes include bloating, gas, colitis, endometriosis, food poisoning, GERD, IBS (irritable bowel syndrome), ovarian cysts, abdominal adhesions, diverticulitis, Crohn's disease, ulcerative colitis, gallbladder disease, liver disease, and cancers. Signs and symptoms of the more serious causes include dehydration, bloody or black tarry stools, severe abdominal pain, pain with no urination or painful urination. Treatment for abdominal pain depends upon the cause.
Boost Digestive HealthUpset stomach? Some foods may be the culprits, and bad habits may be to blame. Treat your body right with these simple nutrition tips on how to deal with with diarrhea, gas, reflux, and more digestive ailments.
Celiac Disease (Gluten Enteropathy)
Celiac disease is a condition in which a person has inflammation of the small intestinal mucosa when exposed to gluten in the diet. Symptoms of celiac disease include bloating, nausea, diarrhea, and abdominal discomfort. Treatment is a gluten free diet. Some individuals may have refractory celiac disease in which they do not respond to a gluten free diet.
Celiac Disease QuizCould celiac disease be the cause of your tummy troubles? Take the Celiac Disease Quiz to learn what certain foods may be doing to your insides. Learn symptoms to look for as well as how to treat this digestive disorder.
Celiac Disease SlideshowDo you suffer from celiac disease? Learn about diet, symptoms, diagnosis, and treatments for this digestive disorder that occurs in reaction to gluten and damages the intestines.
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week. Constipation usually is caused by the slow movement of stool through the colon. There are many causes of constipation including medications, poor bowel habits, low fiber diets, laxative abuse, and hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
Crohn's DiseaseCrohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect other parts of the digestive system as well. Abdominal pain, diarrhea, vomiting, fever, and weight loss are common symptoms.
DiarrheaDiarrhea is a change is the frequency and looseness of bowel movements. Symptoms associated with diarrhea are cramping, abdominal pain, and the sensation of rectal urgency. Causes of diarrhea include viral, bacterial, or parasite infection, gastroenteritis, food poisoning, and drugs. Absorbents and anti-motility medications are used to treat diarrhea.
Worst Foods for DigestionDiscover which foods to avoid in order to prevent diarrhea and digestive problems. Find out which foods can trigger diarrhea and other digestive problems such as gas, bloating, indigestion, heartburn and more.
Gluten-Free DietStarting a gluten free diet? Get the facts about gluten free foods -- with tips on what to avoid, what to enjoy, and delicious, gluten-free alternatives to keep you healthy and happy.
Hydrogen Breath TestThe hydrogen breath test uses the measurement of hydrogen in the breath to diagnose several conditions that cause gastrointestinal symptoms. Gastrointestinal symptoms diagnosed by the hydrogen breath test include:
- lactose intolerance,
- celiac disease,
- small bacterial overgrowth of the small intestine,
- and pancreatic insufficiency.
Intestinal Gas (Belching, Bloating, Flatulence)Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Causes include everything from irritating foods we eat, to certain diseases, and infections. Treatment options include medicine including, local anesthetics, for example, lidocaine (Xylocaine), pramoxine (Fleet Pain-Relief), and benzocaine (Lanacane Maximum Strength), vasoconstrictors, for example, phenylephrine 0.25% (Medicone Suppository, Preparation H, Rectocaine), protectants, for example, glycerin, kaolin, lanolin, mineral oil (Balneol), astringents, for example, witch hazel and calamine, antiseptics, for example, boric acid and phenol, aeratolytics, for example, resorcinol, analgesics, for example, camphor and juniper tar, and
Gas (intestinal gas) means different things to different people. Everyone has gas and eliminates it by belching, burping, or farting (flatulence). Bloating or abdominal distension is a subjective feeling that the stomach is larger or fuller than normal. Belching or burping occurs when gas is expelled from the stomach out through the mouth. Flatulence or farting occurs when intestinal gas is passed from the anus. Causes of belching or burping include drinking too rapidly, anxiety, carbonated drinks, habit, and swallowing air.
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a GI (gastrointestinal) disorder with signs and symptoms that include abdominal pain, bloating, increased gas (flatulence), abdominal cramping, diarrhea, constipation, and food intolerance.
Two new tests are now available that may help diagnose irritable bowel syndrome with diarrhea and constipation (IBS-M) irritable bowel syndrome with diarrhea (IBS-D), and irritable bowel syndrome with constipation (IBS-C). Treatment for IBS includes diet changes, medications, and other lifestyle changes to manage symptoms.
Irritable Bowel Syndrome (IBS) Triggers, PreventionIrritable bowel syndrome (IBS) is a functional disease that can affect the quality of those who suffer from this condition. People with IBS can make lifestyle changes that may modify or control the number and severity of episodes. Certain foods, medications, and hormone levels may trigger IBS episodes, for example:
- Fatty foods
- Dairy products
- Eating foods in large quantities
- Foods that contain high levels of sorbitol
- Foods that produce intestinal gas (broccoli, onions, cabbage, and beans)
- Physiological stress
- Some antibiotics
- Some antidepressants
- Medicine with sorbitol
- Menstrual pain
Lactose intolerance is a common problem where a person's digestive system cannot digest lactose. Signs and symptoms include:
- Abdominal pain
- Abdominal bloating
- Abdominal distention (swelling)
There are several tests to diagnose lactose intolerance. Treatment is generally made with dietary changes, supplements, and adaptation to small amounts of milk.