Diet and Irritable Bowel (IBS): some caveats to keep in mind

By Cristiano Antonino On Apr 12, 2023

Irritable Bowel Syndrome (IBS) is a pathology caused by an important number of different factors: IBS can include gastrointestinal motility disorders, persistent low-grade inflammation of the gastrointestinal mucosa, visceral hypersensitivity, of the gastrointestinal microbiota, alterations of the microbiota, genetic predisposition and stress

But not only. Diet also affects IBS.

It is an element of life to be taken into account, even if only to avoid reaching the doctor’s diagnosis with a compromised clinical picture.

Food indications for irritable bowel: which diet to adopt with IBS?

Since many patients with irritable bowel syndrome report that the meal induces or increases the intensity of the symptoms, it seems that nutrition assumes an important role through chemical, osmotic, mechanical, neuroendocrine, bacterial processes linked to the fermentation of some food substances.

In an article recently published in Current Opinion in Gastoenterology, the authors took into consideration the research carried out on the subject to consider the effectiveness of the dietary approach in the therapeutic management of irritable bowel syndrome.

The first level of dietary intervention consists in avoiding food excesses and limiting the ingestion of substances considered potentially irritating (alcohol, hot spices, stimulants, etc.).

Food and fermentation in the intestine

One option that is of particular interest in the case of irritable bowel syndrome is the low-FODMAP (Fermentable Oligo-Di-Mono-Saccharides And Polyols) diet.

FODMAPs are short-chain carbohydrates that are incompletely absorbed in the gastrointestinal tract and favor the onset of fermentation phenomena in the intestine.

They are contained in many foods, in particular they are abundant in:

wheat derivatives
legumes
milk and dairy products
some fruits (pears, cherries, apricots, figs)
some greens and vegetables (chicory, asparagus, broccoli, peppers).

IBS, the two-phase diet

This dietary approach (Low FODMAP diet) to combat irritable bowel consists of two phases:

in the first part (4-6 weeks) foods containing FODMAPs are eliminated
in the next phase (6-12 weeks) each food category is gradually reintroduced to identify individual intolerances and formulate a less restrictive diet.

Gluten and fermented foods

Although a gluten-free diet has a considerable following, in reality foods with gluten contain FODMAPs (e.g. fructans), therefore the benefit of this diet in some cases of irritable bowel syndrome is partially linked to the exclusion of FODMAPs and, unless it is a clear condition of intolerance to wheat (as for the so-called Non-Celiac Gluten Sensitivity), the exclusion of gluten should be reserved for celiac disease in consideration of the possible consequent associated nutritional deficiencies (vitamin D, vitamin B1, iron, zinc, magnesium).

Supplementing soluble fiber, particularly psyllium, in the diet has been found to be effective in treating irritable bowel symptoms.

Furthermore, interventions to modulate the intestinal microbiota through the use of probiotics represent a promising possibility that needs further confirmation for the identification of the appropriate bacterial strains, for the administration time and for the dosage.