Is Your Gluten Sensitivity Actually FODMAPs Intolerance?

I’ve noticed that even after starting on a gluten-free diet, many of my clients with gluten sensitivity find that other foods can also trigger uncomfortable symptoms like bloating, gas and diarrhea. Some can’t handle certain spices, some fruits like avocados, peppers or bananas and some vegetables like cabbage or artichokes. Many, like myself, weren’t lactose intolerant as adults until they started having gluten-related flare-ups, then found that something like a little ice cream would send them on an urgent path to the bathroom. What these foods have in common are FODMAPs – sugars or small carbohydrates that can ferment in the gut and cause symptoms. Wheat contains several types of FODMAPs, so is it really gluten, or is it FODMAPs intolerance, and how can you tell the difference?

What is FODMAPs Intolerance?

Bloating, gas, abdominal pain or diarrhea experienced anywhere from two to eight hours after eating certain sugars, artificial sweeteners or carbohydrates are symptoms of FODMAPs intolerance. Nausea, vomiting and other symptoms are possible but less common, and constipation may alternate with diarrhea. FODMAPs intolerance is very commonly experienced in those who suffer from IBS (Fedewa & Rao, 2014). 

What are FODMAPs?

The term FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Saccharide means sugar, so a monosaccharide is a single sugar molecule like glucose, fructose or galactose, a disaccharide is two single sugars bound together like lactose (galactose and glucose), sucrose (glucose and fructose) or maltose (glucose and glucose) and an oligosaccharide is a chain of anywhere between three and about eleven sugars. Polyols are also called sugar alcohols because they have an -OH hydroxyl group on each carbon atom, as opposed to a single C-OH found in alcohols (poly=many, -ols=alcohols) (Lenhart & Chey, 2017). 

What Foods Are High in FODMAPs?

Refined carbohydrates like bread, pastries, muffins and other baked goods are made of mostly starch, long chains of glucose molecules that are quickly broken down into individual glucose monosaccharides. Fructose is found in high fructose corn syrup, honey, cane sugar, wheat products like bread and pasta, and, in varying amounts, fruits. High-fructose fruits include tropical fruits like mangoes, papayas, jackfruit and bananas, grapes, fruit juices and dried fruits. Milk is, of course, high in lactose, but fermented dairy products are lower in lactose, because the sugars are eaten by microbes during fermentation. Maltose is found in malted grain products from wheat, rye and barley such as bagels, breads and beer, and as a sweetener in breakfast cereals. Oligosaccharides include fructo-oligosaccharides (FOS), chains of fructose found in wheat, onions, garlic, asparagus, artichokes and bananas and galacto-oligosaccharides (GOS), chains of galactose found in cabbage and beans. Finally, polyols are found in stone fruits like peaches, apricots and cherries, mushrooms, apples and pears, and artificial sweeteners that contain sorbitol, lactitol, mannitol, isomalt or xylitol (Barret et al., 2010). 

What Causes FODMAP Intolerance?

How FODMAPs cause intolerance symptoms depends on the type of FODMAP. Glucose and fructose malabsorption can be caused by a lack of sufficient transporters on intestinal cells to bring enough of them into the body, or in the case of fructose, a lack of enzymes that convert it to its usable form, glucose, which backs up absorption. Lactose can’t be absorbed until it is broken apart by an enzyme produced in intestinal cells called lactase, but those who don’t have the genes to produce the lactase enzyme as adults, or those with damaged intestinal cell function as seen in gluten intolerance or leaky gut, don’t produce enough lactase. FOS and GOS are indigestible fibers, meaning we don’t have the enzymes to break them down. Only about a third of ingested polyols are absorbed through passive diffusion, leaving the rest to pass through the gut lumen. 

No matter the cause of malabsorption, the large amount of FODMAPs particles in the small intestine create an osmotic gradient, where there are more particles in the gut than in the surrounding tissues, pulling water from lower to higher concentration of particles and causing bloating. Increased fluid in the gut flushes the FODMAPs down to the lower small intestine and large intestine, where gut microbes are flooded with a rich food source. They quickly metabolize the FODMAPs, giving off gases such as methane and hydrogen as byproducts and causing gas and painful gut distention or stretching. The gas comes out as flatulence, and the flush of water through the intestines causes diarrhea. Constipation can alternate, as contents of the large intestine can’t be pushed down as efficiently with gas filling the colon, and water is reabsorbed from the stool making it dry and hard to pass (Barrett et al., 2010).

Ultimately, the causes of FODMAPs intolerance are weakened digestion and absorption, dysbiosis, or an imbalance of microbes in the gut, and a high prevalence of certain FODMAP-containing foods in the diet like wheat, high-fructose corn syrup and artificial sweeteners.

Is it FODMAPs or Gluten?

Gluten sensitivity is both a cause and symptom of weakened gut function, so a concurrent FODMAPs intolerance should come as no surprise. In fact, FODMAPs may be responsible for the bloating and gas, and partly the abdominal pain and diarrhea that often come with gluten intolerance. Those who experience only the FODMAPs-related symptoms of wheat in the diet may only have issues with FODMAPs, but whether it's gluten sensitivity or FODMAPs intolerance, starting a healthy gluten-free diet, because it removes wheat, which is a major culprit in FODMAPs intolerance due to its prevalence in the modern diet, will help alleviate symptoms and allow the gut to start to heal.

Should You Avoid FODMAPs? 

Cutting all FODMAPs from the diet is not advised, as not everyone is triggered by all FODMAPs, and many of the FODMAP-containing foods like fruits, vegetables, beans and dairy products are packed with good nutrients and fiber that feeds health-promoting gut microbes. Because many FODMAPs are important for gut healing and maintaining a healthy diet, and studies show that those who try to self-identify their specific FODMAPs triggers are often incorrect, seeing a nutritionist to provide guidance and structure in identifying FODMAPs triggers, replacing them with nutrient-rich foods and healing the gut so that as much food variety as possible can be tolerated is crucial. So if you think you may have FODMAPs intolerance, book an appointment with a nutritionist here.