First developed at the Monash University in 2006, the low-FODMAP diet has proven to help several patients address their irritable bowel syndrome (IBS) symptoms.1 To date, IBS does not stem from any known etiology and many of the theories surrounding its origin are just mere conjecture. What we do know so far is that the temporary restriction of certain fermentable foods might silence the discomfort and self-reported never-ending bloat typically associated with IBS. Each of these fermentable foods that belong in the FODMAP family have been categorized into the following: Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. The foods that belong to these groups are usually stripped down of their basic elements into different types of sugar molecules. If they go undigested through the small intestine, they will certainly meet the gut bacteria at the large intestine where they will be broken down and may cause that lower discomfort. By eliminating all the known culprits temporarily, scientists and now clinicians are confident that they can scope out the root problem. However, critics have suggested that the current supporting data is not definitive and that following a low-FODMAP dietary regimen may cause more harm than good in the long-term.
In a 2017 review, Catassi et al. question the safety of this diet arguing that those who follow it may be at risk for a lower intake of fiber, iron, zinc, folate, calcium, Vitamin D, and B- Vitamins.1 The exclusion of a several foods like lactose-containing dairy products, wheat derivatives, and vegetables may also have unforeseen physiological consequences in the gut lumen as a result. Therefore, it may negatively impact the “good gut bacteria” like bfidobacteria and lactobacillus. Catassi et al. also argued that the data supporting the efficacy of the low-FODMAP dietary regimen does not come from a double-blind randomized controlled trial. Given the current data, the inventors of the diet recommend that patients avoid FODMAPs completely for a total of two months and then introduce each FODMAP food group back one week at a time. If you ask me, such a recommendation is way too long and bound to hurt the patient in the long run. Despite the proposed weaknesses of this diet though, I would argue that it has a lot more strengths. Assuming the diagnosis of IBS is the correct one and we have ruled out any other potential lower bowel issues, a personalized low-FODMAP diet will likely get patients out of their lower bowel woes. As Dieterich and Zopf pointed out, several studies have demonstrated that a low FODMAP diet led to overall gastrointestinal improvement in about 80% of patients.2 I believe a modified version of the low-FODMAP diet would be most appropriate in determining the offending foods without causing any potential harm to the patient. It is important to consider that some of our patients may present with other diseases that already put them at risk for several vitamin deficiencies, malnutrition, or even disordered eating. My recommendation would be to first have the patient document which foods they are eating over the next three days and when symptoms arise throughout each day. I would then instruct the patient to follow a low FODMAP diet that would restrict any suspected culprit foods or associated ones in their current dietary regimen for two weeks. If there is a food group that a patient rarely consumes, I will choose not to restrict such foods even if they present on the FODMAPs list. The goal is to address the current IBS-related symptoms. I would be careful to work with each individual patient and supplement if necessary. Following the two-week low-FODMAP client centered dietary regimen, I will slowly reintroduce each suspected food and titrate the amount each day. During that time, I will assess for any potential IBS related flare-ups.
References
- Catassi G, Lionetti E, Gatti S, Catassi C. The Low FODMAP Diet: Many Question Marks for a Catchy Acronym. Nutrients. 2017;9(292). doi:10.3390/nu9030292
- Dieterich W, Zopf Y. Gluten and FODMAPS – Sense of a Restriction/When is Restriction necessary? Nutrients. 2019;11(1957). doi:10.3390/nu11081957