What are FODMAPS?

What are FODMAPs | Aerhealth Digest

What are FODMAPs

FODMAPs are short chain carbohydrates that are poorly absorbed in the small intestine that can cause or worsen digestive symptoms for people with IBS and other gut disorders. Although they are grouped together, they are in fact different types of carbohydrates and vary in the manner in which they induce symptoms.

FODMAPs stand for: Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and, Polyols

Why Fermentable?

These group of carbohydrates are highly fermentable, serving as energy for our gut bacteria. Since they are poorly digested in the small intestine, when these FODMAPs reach the colon they are rapidly fermented by the bacteria living there. It is this fermentation process which results in symptoms like bloating and gas.

Found in
Oligosaccharides (Oligo – also stands for a few) which have the longest chain length of the FODMAPs are made up of 3 to 7 monosaccharides.
Legumes, wheat, rye, barley, garlic, leek and onions
Galacto- oligosaccharides (GOS) and Fructans
Disaccharides (Di – meaning two) contain two monosaccharides
Milk, buttermilk, goats milk, milk kefir, evaporated milk
Monosaccharides (Mono- which also stands for one) are single sugars.
Apples, pears, watermelon, mango, honey, high fructose corn syrup, sugar snap peas
Polyol (poly- stands for many and ol- for alcohol) are sugar alcohols containing multiple hydroxyl groups. They aren’t sugars or alcohols, but are named so due to their structure partly resembling sugar and alcohol.
Apples, Apricots, Blackberries, Cauliflower, Mushrooms, Snow peas, products that use artificial sweeteners
Sorbitol, Mannitol

What Is The FODMAP Diet?

The FODMAP diet, a treatment strategy used to manage IBS, is an elimination diet and should not be followed for prolonged periods as many high FODMAP foods are nutritious and natural prebiotics which are beneficial for the gut . There are three stages in the FODMAP diet: elimination, reintroduction and personalization phases. It’s NOT a long term diet, it’s a process of exclusion and then reintroduction to determine which FODMAP groups and/or foods are associated with your symptoms. 

What are FODMAPS? - Aerhealth

Think of it as a scientific experiment on yourself with n=1 or in other words only 1 test subject. Remember there are plenty of high FODMAP foods that are healthy and rich in essential nutrients. Hence why it is recommended to follow the FODMAP elimination process with a certified dietician who has a FODMAP accreditation.

People who are sensitive to FODMAPs sometimes find that eliminating gluten and dairy products that cause people with IBS causes them to feel better. It is the presence of FODMAPs in these ingredients rather than a gluten or dairy intolerance that is the cause. In such cases there may be certain quantities of these foods which can be consumed without triggering symptoms, which is why it is important to properly follow the phases of the FODMAP diet.

Tests To Diagnose IBS

Tests to diagnose IBS | Aerhealth Digest

How is IBS diagnosed?

Well to start it’s what’s known as a functional gut disorder, aka a person experiences symptoms yet no abnormalities that could explain those symptoms show up on imaging or lab tests. In other words when someone has diabetes doctors can use a well established and clinically validated biomarker that is HbA1c. Unfortunately functional gut disorders, do not have such biomarkers which is what makes diagnosis trickier. Instead doctors rely on following a process of exclusion in combination with a set of criteria to make a definitive diagnosis.

The reason they follow this process is because many IBS symptoms can mimic that of other diseases, so it’s important to exclude those first. They can then use the criteria known as the ROME scale IV to diagnose you with IBS. It’s important to establish the criteria is met, otherwise further investigations should be undertaken.

Now lets see how that would work in practice :

Patient visits doctor


Doctor gets patient history, symptoms, scans for red flag symptoms (25),


Dr orders tests based on assessment – usually blood tests, stool tests etc


Depending on test results if no red flags and patient symptoms correlate to criteria of ROME IV then diagnosis of IBS can be made

Testing based on sound clinical evidence

Common Blood and Stool Tests that Doctors may Order

  • Full Blood Count
  • C-reactive protein
  • Erythrocyte sedimentation rate
  • Blood test to check for Celiac antibodies
  • Faecal Calprotectin to screen for IBD
  • Blood Test for Thyroxine levels to screen for hyper- or hypo- thyroidism

Limited Testing: Usually conducted in the presence of alarming symptoms or abnormal test results

SeHCAT scan

Abdominal Ultrasound


Alternative Tests – Limited Clinical Evidence

Medical Doctors are highly unlikely to order the following tests or recommend them as there is not enough evidence to show they provide valuable information.

Microbiome Tests

Despite how far we have come with modern medicine and science, there is still a lot we do not know about the wonderful world of our gut microbiomes. For these tests to be useful in diagnosis we would need to identify what the microbiome of someone with IBS looks like versus that of a health person. However researchers have not established a clear microbial signature amongst people with IBS. This can be attributed to the vast differences in our microbiome compositions that is influenced by many factors, especially your diet.

IgG Food Intolerance Testing

This should not be confused with the IgA and tTG blood tests that are commonly used to check for Coeliac disease (28). These tests claim that elevated levels of IgG antibodies to a specific food are indicative of an intolerance. However there is no good evidence to back this up. Rather these antibodies are probably just a normal immune reaction to exposure to that food. Using such tests can be harmful, as you could end up overly restricting your dietary intake if you go by the results to determine trigger foods. Instead a food exclusion and reintroduction test to identify triggers of individual foods or food groups should be conducted under the supervision of a registered dietician to avoid over restriction.

Intestinal permeability testing 

Faecal short-chain fatty acids (SCFA) testing 

Lactose hydrogen Breath Tests 

Glucose hydrogen Breath Tests