Diet Tips:Research article: Not all FODMAPs are equal

By Caroline Tuck (APD, PhD Candidate)

An interesting study was published in 2013 about the effects of different FODMAPs.

FODMAP is an acronym for a group of carbohydrates that have been shown to cause symptoms in people with irritable bowel syndrome (IBS). The acronym stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols and includes the following carbohydrates:

·         fructose

·         lactose

·         sugar polyols (including sorbitol and mannitol)

·         fructans

·         galactooligosaccharides

Although these 5 sugar subgroups have been grouped together, they appear to have a different effects on the gut. This study compared the effects of fructose and fructans.

Sixteen healthy volunteers participated in the study. Subjects were given 4 different solutions: glucose (a well-digested/absorbed sugar) which acted as a control (or placebo); fructan; fructose or fructose with added glucose. After consuming each solution, subjects underwent MRI scans to assess the water content of the small intestine and the gas content of the large intestine.

The study showed that fructose caused an increase in the water content of the small intestine (probably due to osmosis), while fructans increased the gas content of the large intestine. The study highlights that different FODMAPs behave differently, even within the same gut. It also helps us to understand why different FODMAP may contribute to different IBS symptoms. The study suggests that dietitians should tailor a person’s low FODMAP diet to mitigate specific IBS symptoms.  

If you would like to read the full research article, the reference is here: Murray, K., V. Wilkinson-Smith, C. Hoad, C. Costigan, E. Cox, C. Lam, L. Marciani, P. Gowland and R. C. Spiller (2014). "Differential effects of FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols) on small and large intestinal contents in healthy subjects shown by MRI." Am J Gastroenterol 109(1): 110-119.

           

Diet Tips:NEW US RESEARCH: The Low FODMAP diet superior for the relief of abdominal pain and bloating

The Low FODMAP Diet & mNICE Diet Compared

By Dr Jane Varney

 

An interesting study was published by our colleagues at the University of Michigan this week (1). The US study compared the effect of two dietary interventions on IBS symptoms in people with diarrhoea predominant IBS (IBS-D). The interventions in question were the low FODMAP diet and a more traditional dietary approach, known as mNICE (modified guidance from the National Institute for Health and Care Excellence).

Ninety-two eligible subjects were recruited into the study, all of whom had IBS-D and most of whom were female (71%). Participants were randomised to either a low FODMAP diet or the mNICE diet for 4 weeks. Because this was also not a feeding study, a dietitian taught participants how to follow their respective diets, but participants were required to put this advice into practice and prepare their own meals. Resources developed at Monash and Michigan Universities were used to teach participants how to follow the low FODMAP diet. Guidance given to the mNICE group included to eat small frequent meals, to avoid trigger foods and to avoid excess alcohol and caffeine. This guidance was considered ‘modified’, because high FODMAP foods were not specifically excluded as would typically be the case on this diet.

 

 The study revealed a number of interesting findings:

·         The diets were equally effective at providing ‘adequate relief’ of overall IBS symptoms, with improvements experienced in 41% of participants in the mNICE group and 52% of participants in the low FODMAP group.

·         More participants in the low FODMAP group experienced an improvement in abdominal pain, 51% versus 23%, p=0.008.

·         The greatest benefit of the low FODMAP diet was for relief of abdominal pain and bloating, with improvements in stool consistency, stool frequency and urgency also observed in this group.

Take home messages:

·         The low FODMAP and mNICE diets improve symptom control in roughly half of all people with IBS-D.

·         The low FODMAP diet may be a superior choice for the relief of some symptoms, namely abdominal pain and bloating

 

1. Eswaran SL, Chey WD, Han-Markey T, Ball S, Jackson K. A Randomized Controlled Trial Comparing the Low FODMAP Diet vs. Modified NICE Guidelines in US Adults with IBS-D. Am J Gastroenterol. 2016.

Link to full research article: http://www.nature.com/ajg/journal/vaop/ncurrent/full/ajg2016434a.html