What causes FODMAP intolerance?

In an ideal world, if you eat nutritious foods, drink plenty of water, get enough sleep, exercise regularly and avoid stress, you will have a happy, healthy body. But in reality, this simplistic notion doesn’t apply to everyone. For instance, people who are sensitive to FODMAPs could be doing all these things and still feel discomfort in their stomachs, have irregular bowel movements or experience other digestive problems.

FODMAP facts

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. FODMAPs are short-chain carbohydrates (sugars) found in a lot of the foods we eat.

FODMAPs include:

  • Fructans and Galactose-Oligosaccharides (GOS), present in wheat, rye, barley, onions, garlic and legumes.
  • Lactose, a disaccharide found in dairy products like milk, ice cream, yoghurts and soft cheeses.
  • Fructose, a simple monosaccharide naturally occurring in fruits, vegetables, honey, corn syrup and table sugar.
  • Sugar alcohols like xylitol, sorbitol and mannitol contained in some fruits and vegetables, also used as artificial sweeteners.

These carbohydrates cannot be completely digested and absorbed in the small intestine so they make their way to the colon untouched where the gut bacteria break them down for fuel, producing hydrogen gas in the process. This could lead to digestive unrest and distention causing gas, bloating, abdominal pain and constipation in people who have FODMAP intolerance. Additionally, these carbs also have an osmotic effect that draws water with them into the intestines, resulting in diarrhoea.

Intolerance may be dependent on the type of FODMAP and how your body reacts to it as well as the amount of that particular substance you consume.

The most common digestive disorder affected by an intolerance to FODMAPs is IBS or irritable bowel syndrome, apart from Crohn’s disease, ulcerative colitis, and other inflammatory bowel disorders (IBD). When FODMAP-sensitive individuals suffering from these disorders ingest FODMAPs, it could trigger the symptoms of their condition and aggravate it.

How do our bodies become intolerant to FODMAPs?

Our bodies produce biological catalysts called enzymes that break down the food we eat into small molecules. This enables our digestive system to absorb them and use them so we can function properly. But there are people who are not able to make certain kinds of enzymes in the amount needed to digest some substances in the food they eat. Their inability to produce the required type and amount of enzymes is the reason behind their FODMAP intolerance.

Effects of FODMAP intolerance

For a better understanding of FODMAPs and their effects on our bodies, let us first look at what happens to each of them when they enter our digestive tract.

Let’s begin with the oligosaccharides or the carbohydrates that contain the same ratio of hydrogen and oxygen present in water (H2O), and consist of three to 10 monosaccharides. Undigested oligosaccharides move through the small intestine and enter the colon where they are fermented by gut bacteria, causing flatulence, bloating, discomfort and diarrhoea as they make their way out of the body.

Similarly, disaccharides—carbohydrates made up of only two monosaccharides—that are not broken down by enzymes reach the colon and also go through the process of fermentation that creates the same unpleasant effects on the body as that of oligosaccharides. A classic example of this disaccharide is lactose, which is dissolved by the enzyme lactase. As most people get older, their bodies are not able to produce enough lactase causing them to become lactose intolerant.

Simple carbohydrates that are monosaccharides like glucose are easily digested by most people. However, fructose from sugars and sweeteners, processed foods and even some fruits cannot be digested by other people, causing intolerance and imbalance in their gut microbiome that could lead to constipation.

Finally, polyols or sugar alcohols such as xylitol, sorbitol and mannitol that are added to foods as sweeteners are not readily digested and absorbed into the bloodstream. Just like the first three carbohydrates, polyols travel through the small intestine and into the colon where they are fermented by gut bacteria and, in the process, bring about symptoms of FODMAP intolerance before they are eliminated by the body.

Moreover, clinical research discovered that small intestinal bacterial overgrowth or SIBO contributes to FODMAP intolerance as well as the development of IBS symptoms in some patients.

SIBO or imbalance in the gut microbiota can result in FODMAP intolerance and occurrence of IBS symptoms. Similarly, over-fermentation of carbohydrates in the small intestine caused by pathogenic bacteria could increase the production of hydrogen gas and bad bacteria in the colon, thereby creating gut dysbiosis.

Lastly, experiencing stress of all kinds is also a possible cause of FODMAP intolerance because of how it influences the gut microbiota.

The low-FODMAP diet

Most of the foods we eat contain FODMAPs, but how they affect our bodies vary from person to person. This is why the best solution for FODMAP-sensitive individuals to reduce the effects of FODMAPs is for them to go on a low-FODMAP diet.

The low-FODMAP diet entails temporarily removing a lot of foods that contain FODMAPs from your diet. This can be tricky as you should still be able to get the right amount of nutrients your body needs. Seeking the help of a medical professional or a FODMAP-trained dietitian is highly advised because they can recommend substitutes for the FODMAP-rich foods you took out of your diet, which can prevent your malnutrition. You may also be given supplements to help increase the enzymes that your body could not otherwise produce on its own.

The first phase of this diet involves eliminating foods high in FODMAP from your daily consumption for a two- to six-week period (or as advised by your dietitian). The second phase requires gradually reintroducing them to your diet and observing how your body responds to each of them. Once you have determined which foods are triggering your symptoms, then you can better address and manage your FODMAP intolerance.

Other ways to improve your gut and reduce the effects FODMAP intolerance is by taking probiotics to help maintain the balance of your gut microbiome and getting treated for SIBO.

Need Our Help?

Book an appointment with an accredited dietitian or nutritionist by phone on (07) 3071-7405 between 8am and 6pm Monday to Friday or send us an enquiry. Alternatively, find out more about our Gut and Bowel Health services.