Before You Give Up Gluten, Try a Low-FODMAP Diet

Date: June 23, 2015      Publication: Bottom Line Health      Source: Peter  Gibson, MD, The Alfred and Monash University      Print:

These days just about everyone has a friend who has gone on a gluten-free diet and raves about it. Perhaps you’ve tried it yourself. Perhaps digestion improves, and so does well-being. Does that mean that you or your friend is sensitive to gluten?

Maybe not. Surprisingly, you may actually be reacting to a different ingredient in wheat…and in many other foods. Avoiding this particular class of hard-to-digest carbohydrates, called FODMAPs, may improve digestive symptoms in people who believe that they are sensitive to gluten.

That’s not to say that gluten is suddenly fine for everyone. It’s pure poison for the two million Americans with celiac disease, a digestive disease in which the body can’t digest gluten, a protein found in wheat, rye and barley. Nor does it mean that non-celiac gluten sensitivity (NCGS) isn’t real. It’s just that the population with NCGS may be smaller than once believed—and certainly fewer than the 30% of Americans who currently try to avoid gluten in their diets.


The good news is that a careful plan to remove just the FODMAPs that are causing your particular reaction may lead to a less restrictive diet than a gluten-free one—and be more effective in fixing your digestion.


To understand the FODMAP/gluten story, step back to 2011. Australian researchers studied people who didn’t have celiac disease but did have irritable bowel syndrome (IBS), with its symptoms of bloating, stomach pain, and diarrhea and constipation. (As many as 20% of Americans experience these symptoms in this often-undiagnosed and poorly understood condition.) In a randomized placebo-controlled study, the Australians reported that gluten made the 34 study participants’ IBS symptoms worse and that a gluten-free diet reduced symptoms.

That very influential study helped establish the concept of non-celiac gluten sensitivity and boosted the popularity of gluten-free diets.

But then a couple of years later, the same researchers revisited the topic. They examined whether gluten was indeed the cause of symptoms in a group of people who had NCGS. These 37 patients “felt that gluten was the cause of their gut symptoms” says the study’s lead author, Peter Gibson, MD, professor and director of gastroenterology at The Alfred and Monash University in Melbourne, Australia. The study also looked at the effects of FODMAPs, which stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. They’re found in many foods, and some studies were starting to find that they could trigger IBS symptoms.

What the Australians found was surprising…


  • A low-FODMAP diet significantly reduced gastrointestinal symptoms.
  • Participants who had reported improvements in GI symptoms on a gluten-free diet before the study had even fewer symptoms on a low-FODMAP diet.
  • When the researchers “challenged” 37 of the participants by giving them food that contained either no gluten, a small amount of gluten (2 grams), or a large amount of gluten (16 grams, about the amount in 10 slices of wheat bread), there was no difference in symptoms. In other words, gluten had no effect on symptoms.

While the study had a small number of subjects (as did the 2011 one), it was carefully designed to provide reliable clinical results. Not only was it double-blind, so that neither researcher nor subject expectations could affects the results, and placebo controlled, but it was a “cross-over re-challenge” study—each participant got each one of the different diets. “This kind of study is the gold standard way of determining whether a food is causing symptoms,” says Dr. Gibson. “If gluten was the cause of the symptoms, then it would cause greater symptoms than the placebo. It did not. That is why gluten is unlikely to be the culprit in those subjects studied.”


Since that study was published, the benefits of a low-FODMAP diet for people with digestive symptoms has become even clearer. Researchers who’ve been looking for ways to help people with IBS, for example, are almost giddy with excitement—well, as giddy as scientists get in print—with editorials such as “Diet as a Therapy for Irritable Bowel Syndrome: Progress at Last.” One 2014 study of the low-FODMAP diet for IBS concluded: “This high-quality evidence supports its use as a first-line therapy.” A recent study of dieticians found that in their experience, a low-FODMAP diet helps patients with GI symptoms better than the old advice to “eat a healthy diet” while restricting lactose-containing foods and cutting back on caffeine.

To be sure, the debate over whether NCGS is a distinct clinical diagnosis, unrelated to FODMAP sensitivity, at least for some people, continues. One 2015 scientific review concluded that it is not clear whether what is thought to be NCGS is caused by gluten or FODMAPs, for example. However, Alessio Fasano, MD, director of the Center for Celiac Research and Treatment at the MassGeneral Hospital for Children in Boston, pointed out in a 2015 scientific review that people with NCGS often have immunological reactions to wheat and other grains—not just stomach problems. NCGS may contribute to other conditions including chronic fatigue syndrome and autoimmune diseases, he argues. To make matters even more complicated, there are other ingredients in wheat, rye, and barley, such as amylase-trypsin inhibitors (ATIs), that may trigger immune response–related symptoms. He believes a better name for NCGS is non-celiac wheat sensitivity. Going on a low-FODMAP diet wouldn’t address these concerns.

For now, though, if you have unresolved digestive symptoms, it’s clearly time to give a low-FODMAP diet a close look. “Our advice is to try reducing FODMAPs first, since this is an easier diet than a gluten-free diet,” says Dr. Gibson. Based on research, he estimates that about 70% of people with IBS symptoms will benefit.


“The major argument against the low-FODMAP approach is that it is too difficult, but that is the opinion of people who do not know much about how easy the low-FODMAP diet is to implement,” says Dr. Gibson.


It is true that FODMAPs are very common in a typical Western diet. FODMAPs include fructans, found in wheat as well as onions and garlic…fructose, high-fructose corn syrup, and some fruits such as apples and pears…lactose, the sugar in milk and other dairy products…polyols, found in the sweetener sorbitol and in stone fruits such as plums and cherries…and galacto-oligosaccharides, found in beans, lentils and soybeans. However, many individuals are more sensitive to some FODMAPs than others. It’s also the dose of FODMAPs that counts—a little bit is OK but a lot will cause symptoms. So you may need to reduce FODMAPs a small amount to feel better. (That’s why it’s a “low-FODMAP” diet, not a “FODMAP-free diet.”)

That’s good, because many of these foods are very nutritious. It’s best, by far, to get help from a dietician if you want to see whether you would feel better on a low-FODMAP diet—a dietician will guide you through a FODMAP-elimination process in which you will get rid of most or all FODMAPS and then carefully add each type back, in turn, to see which ones cause your symptoms. A dietician can also help make sure you eat a nutritious diet even if you need to eliminate certain classes of foods. To learn more, Monash University has created a low-FODMAP app with information on low- and high-FODMAP foods as well as meal plans.

If you continue to have problems and suspect gluten, on the other hand, do get it checked out. The first action is to find out if you have celiac disease, and there are well-established tests for this. Don’t give up gluten until you know, because having eaten gluten is key to the diagnosis. You may also want to check for a wheat allergy, which is a different beast entirely. If the FODMAP diet doesn’t help and other conditions such as Crohn’s have been ruled out, you may want to consider gluten. Unfortunately, there aren’t lab tests that can establish gluten sensitivity, but you can work with your doctor to go on a gluten-free diet to see if it helps your symptoms. But that should be your last step in this process—not your first!

Source: Peter Gibson, MD, is professor and director of gastroenterology at The Alfred and Monash University, Melbourne Australia. He is a recipient of the Gastroenterological Society of Australia’s Distinguished Research Prize. For more information on FODMAP diets, check his department’s website.

  • sky35

    Great idea for some people to avoid FODMAPs, but also pay attention to the fact that many of the mentioned symptoms can be caused by GMOs and/or Roundup/glyphosate, ( and other agricultural poisons) . A good first step is to ONLY EAT REAL FOOD…..cut out all the processed, chemical-laden non-food that we put into our bodies. Then experiment with the above advice if you still need to.
    Studies that do not take into account gene-altered food and poisons can have skewed results, sometimes blaming substances in food that are only a problem in their altered versions

    • DenisBH

      Interesting comment. Can you provide link(s) to one or more references (reliable references, please) that substantiate it? Thanks.

      • S Johnson

        Denis. There’s a great website called Google that allows you to find answers and information on all sorts of topics. I know Google and other search engines haven’t been around very long but here’s just one article on roundup AKA Glyphosate.

        • DenisBH

          Golly gee, S. Johnson, dat dere website Google sure do have some numerous letters and fancy numbers on it! Well, I never!!

          Yeah, I’m familiar with Google. I asked for at least one RELIABLE reference because I don’t have all day (or all week) to paw through hundreds or thousands of hits.

          And, Mercola?! I’m not going to waste my time. He’s wackier than Larry, Moe, and Curly all wrapped up into one (oh, what the heck, throw Shemp in there as well). Like Food Babe, in it for the money, even more clearly than she. Here’s one of those websites your Google showed me on him:

      • S Johnson

        Here’s a video from Dr. William Davis, the author of Wheat Belly and why the form of wheat we eat is so problematic. This website is called “Youtube”.

        • DenisBH

          Come on, now. Educate yourself beyond this pseudoscience crap. The references you’re providing are the mental equivalent of pesticide-laden foods and GMO-altered versions of food science, human metabolism, and nutrition.

      • sky35
        .scroll down to the bottom of the main page to the “Issues” section, and
        click on “Food and Agriculture” , then scroll quite a ways down that
        page to “Genetic engineering in agriculture”
        for info on what the FDA’s scientists said about the dangers of GMOs.

        ultimately, each person will decide whether to eat poisons or not…if someone can not figure out if it is a good idea to eat poisons, then reading more info may not do much good.

        • DenisBH

          I came across this on their website: “In short, there is a lot we don’t know about the long-term and epidemiological risks of GE—which is no reason for panic, but a good reason for caution, particularly in view of alternatives that are more effective and economical.” The one example they cite (and the only one) of known risk of GMO foods is the use of pesticides on crops engineered to be resistant. I’d say that falls into the category of avoiding pesticides, rather than GE/GMO issues.

    • DenisBH

      Food Babe? FOOD BABE?!?! You must have missed, in my original reply, the reference to RELIABLE references. She, like many in the food-scare industry, is in it to make money. She didn’t even know the difference between propylene glycol and propylene glycol alginate. The former is in antifreeze and the latter is derived from kelp. She has no background in nutrition, which she admits. She claims to be an “investigator.” Well, OK then. Not a very good one at that.

      Understand, I believe in eating organic food whenever possible in order to avoid the pesticides used in conventional food. I am less concerned about GMO foods, but don’t eat many because of my organic diet.

      • sky35

        A person who is wrong on one particular comment is not necessarily wrong on other issues. …but eat GMOs if you want to be like a lab rat in Monsanto’s uncontrolled experiment….keeping in mind that real lab rats have one advantage over you in that they do not PAY to be experimented on.

        There is a lot of information available explaining the harm of GMOs….as the other commenter said, do a Google search …i am not here to argue with fools, but to help wise people avoid the dangers of GMOs.

        Many so-called experts used to proclaim that all of the following were safe :
        Cigarettes….PCBs….DDT…radon…..Agent Orange….hydrofluorisilicic acid , glyphosate…..high fructose con syrup……NOW we know better…..GMOs are not good for people who care about good health, but they are okay if you like the above stuff, just one more nail in your coffin.

        • DenisBH

          “A person who is wrong on one particular comment is not necessarily wrong on other issues.” Of course not, but such a glaring error (and I cited only one of many) takes her out of the category of being a RELIABLE reference. And it certainly doesn’t reflect all that well on the soundness of YOUR assertions either, if you’re citing her as a reliable reference.

          I thank you for your concern regarding my health. As I’ve noted elsewhere in the comments on this story, my ingestion of GMO-food is minimal to none, as I eat organic whenever that is available. It’s just that unbiased sources of information (with no monetary gain involved in convincing anyone of their point of view, unlike the Food Babe and Mercola) do not demonstrate definitive harm from GMO. It is prudent to be circumspect about GMO foods but, in the absence of objectively demonstrated harms, I have less concern about them than I do food with chemicals. Not no concerns, just fewer.

          A Google search turned up these 2 sites which appear RELIABLE: and . And, regarding the safety of GMOs, here’s a link to an article from the 2nd website: . It’s a nice treatment of safety, but it’s a bit long and a bit technical, so it may be overwhelming for you. If so, I apologize. To really understand some of this stuff, you need to have the intellectual capacity to understand it along with a non-ADD attention span along, of course, with an open mind.

          Good luck and good health.

          • Pricilla

            GMO, really?! Why do wet NEED GMO products at all. They have no taste, they DO CAUSE ADVERSE reactions upon eating them. I also take exception to an argument about RELIABLE research and then post something as, “2 sites which appear RELIABLE:” If you don’t KNOW it to be reliable, then why would we give it more credit than any other? Personally I prefer to stay away from anything FDA approved. Pretty sure it’s safe that way. Also, aren’t most RELIABLE reports the opinion of a person? Especially if not backed up by hard data. Undisputable data. The kind found in the documentary “FORKS OVER KNIVES”

    • Lily9241
  • 99bonk

    The July issue of Eating Well magazine contains a well-researched, careful article by Barry Estabrook about GMO foods. Well worth reading and considering.