Gluten on the Low FODMAP Diet: It's Okay to Have Some
By Erin Peisach, RDN, Owner of Nutrition by Erin

Have you already tried modifying your diet to help address your irritable bowel syndrome (IBS) symptoms?

Most people likely turn to a gluten free diet as an excellent starting point for dietary change.

When desired results are not apparent, then it may be time to try out the full low FODMAP elimination diet.

While there is some crossover between the two diets, this article outlines key differences between the gluten free and low FODMAP diets. The gluten free diet is your normal diet, but excludes all sources of gluten.

Now, this may sound fairly straight forward, until you learn a bit more about what gluten is and where it’s hidden.

Gluten is essentially a protein found in wheat, barley, rye, kamut, spelt, and some other ancient grains. You may think it is easy enough to avoid those grains and focus on gluten-free grains like rice, quinoa, and buckwheat, but this ubiquitous protein can also be found in a wide array of processed foods.

The gluten protein can act as a glue helping to thicken, bind, flavor, and even color certain food products. Foods that are seemingly grain-free like salad dressing, processed meats, soy sauce, and candies can often have some sneaky sources of gluten inside!

The good news is that these days gluten-free labeling is fairly common and informs the consumer if the product has <20 ppm gluten per serving (aka pretty safe). 

Who Should Follow a Gluten-Free Diet?
First and foremost, those diagnosed with Celiac disease (CD), an autoimmune condition, are instructed to follow a 100% life-long gluten-free diet for disease management. Even cross-contamination with gluten can be problematic for this population.

People with other types of digestive and autoimmune disorders like Crohn’s disease, Ulcerative colitis, non-celiac gluten sensitivity (NCGS) and IBS may also benefit from the gluten-free diet.

However, it is not medically necessary to follow the diet as strictly as in the case of CD. Benefits can be experienced even by reducing gluten intake.

What is the Low FODMAP Diet?
The low FODMAP elimination diet is commonly recommended to help manage IBS and other types of digestive issues.

FODMAP is an acronym:
• Fermentable - bacteria enjoy eating these foods and produce gas a byproduct
• Oligosaccharide - fructans, galactans/galacto-oligosaccharides (e.g. wheat, barley, garlic, onion, legumes)
• Disaccharide - lactose (e.g. milk, ice cream, sour cream)
• Monosaccharide - excess fructose (e.g. apples, pears, honey, agave)
• And
• Polyols - sugar alcohols including sorbitol, mannitol, xylitol (e.g. stone fruits, mushrooms, diet sweeteners)

The elimination phase of the diet is followed for at least 2-weeks, or until significant amount of symptom improvement is noticed. Thereafter, the challenge and maintenance portion of the diet is implemented.

Overall, the diet limits certain foods that are either gas producing or have an osmotic (water-pulling) effect on the bowel. Eating too many of these high FODMAP foods often causes gas, bloating, distension, abdominal cramping, loose stools, and/or diarrhea. This is not a diet of perfection or absolutes.

Why is There Confusion Between the Diets?
Many believe that when they start the low FODMAP elimination diet, that they are also following a gluten free diet.

This is not the case.

Confusion arises when one notices that wheat, barley and rye are on the “high FODMAP” food lists circulating the internet. The tricky thing is that the carbohydrate component of these grains (aka the fructans) make them high FODMAP. The protein (aka the gluten) component does not.

While gluten-containing food intake may drastically decrease while on a low FODMAP diet, it is not required to follow strict gluten-free diet. Overall, the dose definitely makes the poison!

Gluten-Containing Foods That Are Low FODMAP
According to the Monash University Low FODMAP application, there are quite a few low FODMAP foods that contain gluten.

This app uses the “stoplight method” to indicate if a food is green (good), yellow (moderate), red (avoid) for the FODMAP diet. Did you know 1 slice (35g) of USA white (wheat) bread gives you the green? Also, USA wheat-based sourdough bread (2 slices, 109g, check for yeast-free) is also a green light!

Even certain biscuit cookies (2 biscuits, 20g) and soba noodles (⅓ cup, 90g, made from wheat and buckwheat) are considered low FODMAP. Soy sauce contains wheat (gluten) and is also free to use during the diet.

Not bad, right? They key is checking the app because there are variations of these products that are in the red.

Gluten-Containing Foods That Are Not Low FODMAP
You may think you’re in the clear if you head to the grocery store and shop in the Gluten Free aisle, pulling all the cookies, breads, cereals, pretzels and crackers your little heart desires.

Think again.

While these products are likely certified gluten free, they may not be suitable for the low FODMAP diet. That’s because they can contain other added ingredients that are “No-Nos” like added fibers, milk and sweeteners.

Here’s a great example of this in action.

You are craving something sweet, but want to be healthy and stay on your diet plan. You reach for the ever-so-popular Kind bar. Peanut butter Chocolate sounds delightful!

You see on the front that this bar is gluten free. Score!

Now, let’s look at the back of the label, just to double check a few things…

I spy a few high FODMAP ingredients in there: almonds (less than 10 are okay), honey, chicory root fiber.

Let’s put that bar back just to be safe. A better alternative may be the Go Macro peanut butter chocolate bar!

Common examples of “hidden” high FODMAP ingredients in gluten free foods: inulin, chicory root, apple/pear, apple fiber, fructo-oligosaccharide (FOS), high fructose corn syrup, agave, milk, milk solids, whey protein concentrate, buttermilk, garlic, onion, sorbitol, mannitol, xylitol, isomalt, soy flour, soy milk, lentil or chickpea flour, etc.
*this is not a complete list, just common examples.

Low FODMAP is not Gluten Free
You can see that there are some crossovers between the two diets, but overall you are not on a gluten free diet if you follow the low FODMAP diet.

Be sure to check in with the Monash FODMAP app as updates are readily available as more foods from across the globe are assessed.