Research published in ‘Gut’ journal, a peer reviewed journal for health professionals in the field of gastroenterology, recently reported significant improvements in a group of 19 IBS patients who were put on a low FODMAP (fermentable oligosaccharides, disaccharides and monosaccharides and polyols) diet, as compared to a control group, of 18 IBS sufferers, who were put on high FODMAP diet. The subjects all had their symptoms monitored over a period of three weeks, using both IBS ‘symptom severity scoring’ (SSS), lactulose breath testing (LBT), urine metabolic profiling and stool microbiota composition analysis.

FODMAP foods:

Before we look at the results of the trial, let’s take a look at the type of foods that need to avoided in order to adopt a low FODMAP diet. They are:

Fructose (fruits, honey, high fructose corn syrup (HFCS), etc)

Lactose (dairy)

Fructans (wheat, garlic, onion, artichoke, inulin etc)

Galactans (legumes such as beans, lentils, soybeans, etc)

Polyols (sweeteners containing isomalt, mannitol, sorbitol, xylitol, stone fruits such as avocado, apricots, cherries, nectarines, peaches, plums, etc).

Otherwise healthy foods such as artichokes may trigger IBS symptoms

That's a long list (!), making this a tricky diet to adopt, so it is good to see that there is ongoing research looking at the potential benefits of making the necessary dietary changes, and the physiological reasons for those benefits.

Trial results:

Results from the lactulose breath testing of the trial participants showed a decrease in hydrogen production in the low FODMAP diet group compared with the high FODMAP group. High levels of hydrogen in a breath test suggests carbohydrate malabsorption in the intestines, which can be due to low levels of ‘friendly’ bacteria, or an increase in pathogenic bacteria.

Metabolic profiling of their urine showed that the two groups of IBS patients differed significantly after the diet (p<0.01), with lower levels of three metabolites (histamine, p-hydroxybenzoic acid, azelaic acid) being found in the low FODMAP group. Histamine, a measure of immune activation, was reduced eightfold in the low FODMAP group (p<0.05), which could likely be the reason behind many of the symptom improvements.

Finally, the stool microbiota analysis showed that the low FODMAP diet had an increased diversity of bacteria from the Actinobacteria phyla of microbes, whereas the high FODMAP diet decreased the relative abundance of bacteria involved in gas consumption. In general, when we talk about the health of our gut flora, the greater the diversity, the better. Dietary changes or supplements that promote greater bacterial diversity, generally bring health benefits with them.


Bearing all of the test results in mind, this trial suggests that IBS symptoms could indeed be affected by dietary FODMAP content. The inclusion of these dietary saccharides and polyols seem to create chemical changes within the gut that include the production of excess histamine, and therefore induces symptoms such as bloating and cramping, that are typically seen in IBS patients.

Whilst a FODMAP diet is restrictive, and arduous to follow it appears that it may be helpful for some. However, there are other factors that are also worth considering if you suffer from IBS. Food intolerances are common in sufferers of IBS, as are insufficiencies of digestive enzymes and stomach acid. Alterations in gut flora also often play a strong contributory part in the condition, and may be addressed through the use of a well researched, high-quality probiotic, such as our 'For every day EXTRA Strength' that has been clinically trialled for IBS.

You can read about this clinical trial here, or for more information about IBS in general, you may like to read the following FAQ:

Which probiotics are for IBS? or, the following blog post:

Remedies for IBS - new guidelines promote probiotics.
Reference: FODMAPs alter symptoms and the metabolome of patients with IBS: a randomised controlled trial
Keith McIntosh,, David E Reed, Theresa Schneider1, Frances Dang1, Ammar H Keshteli, Giada De Palma, Karen Madsen, Premysl Bercik, Stephen Vanner

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