Thursday, 8 October 2015

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.
           


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