FODMAP, which stands for fermentable oligo-saccharides, di-saccharides, monosaccharides and polyols, are different types of starches and sugars.

In addition to balancing a person’s gut bacteria, following a low FODMAP diet is one of the most effective methods to reduce symptoms of inflammatory bowel disease (IBS), small intestinal bacterial overgrowth (SIBO) and other gastrointestinal disorders.

What are FODMAPs?

FODMAPs are specific types of short-chain carbohydrates that some people find difficult to efficiently absorb. They are sugar molecules that are linked together in chains and they are fermentable by the bacteria in your gut. Instead of being absorbed into your bloodstream, they reach the far end of your intestine, where most of your gut bacteria live. Certain bacteria in your digestive tract then start to feed on these carbohydrates, using them for fuel, producing hydrogen gas and causing digestive symptoms in sensitive individuals.

These bacteria produce byproducts and waste materials that can lead to symptoms such as gas and bloating. They may also use these FODMAPs to draw liquid into your intestine, which may cause diarrhea.

This can also lead to an overgrowth of these bacteria in the small intestine which can contribute to several other health problems.

So, what does FODMAP actually mean? These carbohydrates can be broken down into categories:

Fermentable: This refers to the process in which gut bacteria ferment undigested carbs producing gases.
Oligosaccharides: These are sugars including fructans and galacto-oligosaccharides (GOS) found in wheat, spelts, rye, barley, onions, garlic and legumes.
Disaccharides: lactose is a carbohydrate found in dairy products such as milk, soft cheeses, and yogurt.
Monosaccharides: Fructose is a simple sugar found in many fruits and vegetables that also makes up the structure of table sugar and other forms of sugar such as honey, high fructose corn syrup and agave.
Polyols: These include xylitol, sorbitol, maltitol and mannitol, which are found in some fruit and vegetables and are used in artificial sweeteners. [1]

How can FODMAPS affect you?

For some people, high FODMAP foods can aggravate irritable bowel syndrome and inflammatory bowel disease symptoms. These symptoms can include:

diarrhea or constipation
gas
bloating
flatulence
abdominal pain

They can also contribute to non-digestive symptoms like fatigue, brain fog, body pain, and mental health symptoms like anxiety.

Why are some people sensitive to FODMAPs and others don’t have any trouble?

FODMAPs aren’t bad for everyone. Our digestive systems are designed to process some foods that we can’t fully digest ourselves such as dietary fibre which is vital to our digestive health. And feeding the bacteria in our gut is part of our symbiotic arrangement with those bacteria. But some people with sensitive guts experience a level of indigestion from these foods that significantly impacts their quality of life. [2]

While most IBS patients are FODMAP intolerant, consuming FODMAPs does not actually cause IBS; it simply exacerbates symptoms. [3]

There are three main reasons you may have trouble digesting these short-chain carbohydrates:

You may lack the right enzymes to digest them. An example would be lactose intolerance. If you lack the enzyme lactase, you may have trouble digesting lactose, the sugar in dairy products.
You may have an overgrowth of gut bacteria in your large or small intestine that likes to feed on and ferment these sugars. [4]
This is known as SIBO. SIBO (small intestinal bacterial overgrowth) is an imbalance of the microorganisms in your gut that maintain healthy digestion. When too many bacteria, or the wrong kind, populate the small intestine, it can lead to uncomfortable symptoms such as gas and diarrhea. It can also inhibit your ability to digest and absorb nutrients from food. [5]
Emotional and physical stress can contribute to the development of IBS and may cause FODMAP intolerance as stress impacts the gut microbiome significantly.

IBS and SIBO display many of the same symptoms and underlying causes. Additionally, there’s a good chance that if you have one of these conditions, you have the other. One study found as many as 78 percent of IBS patients also had SIBO. [6]

If these conditions are left untreated, you may experience further health complications such as malnutrition. When your gut is not absorbing nutrients, it can cause weight loss, chronic fatigue and damage to the way your body works overall.

Serotonin and the gut

A recent study revealed how a low FODMAP diet can help heal and repair the intestines by increasing serotonin levels in the gut.

Neurotransmitters, such as serotonin, are produced primarily in the gut with the help of the trillions of microbes that reside there. Serotonin (5HT) is one of the most important signaling molecules involved in the peristaltic reflex, which moves food along in our digestive tract, and it’s believed that alterations in serotonin signaling may be responsible for IBS symptoms. [7]

About 90 percent of serotonin in your body is created in the gut, helping with pain and keeping food moving through the digestive system.

What is a low FODMAP diet?

There is emerging data that the specific carbohydrate diet (eliminates all dietary disaccharides, oligosaccharides, and polysaccharides) and low FODMAP diet may help reduce symptoms in people with inflammatory bowel disease. [8]

The FODMAP program is typically undertaken in three phases:

Elimination: Remove all high-FODMAP foods for 4-8 weeks. If FODMAPs are the issue, symptoms should reduce significantly during this time.

Reintroduction: Return to your healthcare provider to evaluate the results of the Elimination phase. If you have had a positive response, consider reintroducing FODMAPs slowly and specifically, one at a time, while closely monitoring for the reemergence of symptoms. This will give you a good idea of what exactly what was causing your symptoms. There aren’t really any established guidelines on how to best do this – it varies from person to person.

Maintenance: A long-term eating plan can be designed with your healthcare provider that includes the addition of foods that seem to be tolerated (in both quality and quantity) and continued avoidance of foods that cause negative symptoms. [9]

Many FODMAP-sensitive people can eventually return to their usual diets, provided that they avoid just the few high FODMAP foods to which they are most sensitive.

Unprocessed, whole foods are essential to a low FODMAP diet. Some of the recommended foods include:

All meats and fish (except processed meats such as sausages, salami)
Eggs
Unripe bananas
Blueberries
Grapes
Lemons
Limes
Cantaloupe
Honeydew
Pineapple
Strawberries
Raspberries
Oranges
Canned lentils
Canned chickpeas
Canned pumpkin
Carrots
Chives
Collard greens
Okra
Potatoes
Turnips
Butter
Unsweetened teas (especially green tea)
Water

Here are the items to AVOID if you have IBS:

Onions
Garlic
Wheat
Artichokes
Barley
Broccoli
Brussels sprouts
Cabbage
Cauliflower
Sweet potato
Legumes
Beans
Apples
Celery
Plums
Watermelon
Most fruits
Milk
Honey
High-fructose corn syrup
Sugary drinks
Artificial sweeteners, such as sorbitol, mannitol, maltitol and xylitol

There are many similarities between IBS and gluten intolerance so this can further complicate things. Gluten-free grains also tend to be low in FODMAPs like fructans and galacto-oligosaccharides so when following a low FODMAP diet, people with gluten intolerance often experience a symptom reduction. It’s not clear, however, if it is due to the lower FODMAP content of gluten free foods or the removal of gluten itself. [10]

Who should try the low FODMAP diet?

If you have been diagnosed with IBS, SIBO or another digestive disorder, it’s important to consult with your practitioner to ensure the low FODMAP diet is for you. As the diet can be challenging during the first restrictive phase, it’s important to work with a doctor or dietitian who can ensure you’re following the diet correctly, this is crucial to success and to ensure you continue to consume the nutrients you need to be healthy.

If you have not been diagnosed with a digestive disorder, the low FODMAP diet may not be suitable for you. Eliminating FODMAPS, which are prebiotics that support gut health, could do you more harm than good. You’ll also be missing out on major dietary sources of vitamins and minerals.

It may be good for you if you:

have ongoing gut symptoms
haven’t responded to stress management strategies
haven’t responded to first-line dietary advice, including adjusting meal size and frequency and restricting your intake of alcohol, caffeine, spicy foods, and other common trigger foods [11]

How we can help

A diet is one way that you can take charge of your own health. Several studies indicate that a low FODMAP diet enhances overall quality of life by significantly reducing symptom severity for those with IBS, SIBO and other digestive disorders. A low FODMAP diet should not be followed as a long term diet, more a means to assess food intolerances and repair the gut with a plan to try and reintroduce many of the foods.

Whether you have already been diagnosed with a digestive disorder or are just beginning the journey to find out possible causes and cures for your symptoms, our highly qualified Functional Medicine health practitioners at Advanced Functional Medicine can help.

We can help you understand if the low FODMAP diet is the right diet for you and if it is, guide you through it and assist when problems arise. This diet can be tricky to navigate as there’s a lot to learn and remember, especially when it comes to which foods are okay to eat, as well as how much of them you can eat and most importantly how long you should stay on a restricted diet..

We’ll give you the tools to care for yourself and be well. Contact us today to find out more.

How do FODMAPS affect your digestion?