Fructose and lactose intolerance are common and frequently overlap in FGID

The title of this post is a quote taken from the paper by Clive Wilder-Smith and colleagues* (open-access) who reported that issues with the metabolism of the short chain carbohydrates (sugars) fructose found in fruits and lactose found in milk and dairy products may very well be common in functional gastrointestinal disorder (FGID).

Soup again! @ Wikipedia 

I was interested in this paper on two levels.

First is a passing interest in all things FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) and some potential relationship to cases of FGIDs specifically with irritable bowel syndrome (IBS) in mind**. Indeed, I've passed mention about this on a previous post on a sister blog (see here).

Second is, as those who read this blog regularly (thank you!) might know, my interest in all things comorbidity with the autisms in mind. Specifically that growing body of evidence (peer-reviewed of course) suggesting that gastrointestinal (GI) issues might be present in a fair few cases of autism (see here). That and the links suggested between such GI issues and reports of various dietary links (see here).

Certainly on that last point, I'm entertaining the possibility that where clinician-defined FGID (constipation, diarrhoea, even IBS) is found in cases of autism  one might be so inclined to enquire whether there may be issues with fructose and lactose also comorbid.

Just in case you're thinking that I'm getting a little ahead of myself with such speculation, I should point out that: (a) autism is seemingly protective of nothing when it comes to comorbidity and (b) certainly on the issue of lactose, and in particular lactose intolerance, there is more than one study suggesting issues to be present in cases (see here) and perhaps even issues more generally with carbohydrate metabolism as per the 'game-changer' work of Brent Williams and colleagues (see here) and subsequent others (see here). At the very least there is a study there waiting to happen. Fructose by the way, has also been mentioned with autism in mind albeit rather speculatively (see here).

Just before I go there were a few other pertinent points to take from the Wilder-Smith study. "Dietary modification based on fructose and lactose intolerance testing was clearly beneficial". In other words, when it came to the presentation of FGIDs, for those who were shown to be "sugar" intolerant, there was quite a bit of relief reported. Interesting too that the authors talk about an "elevated prevalence of non-GI functional syndromes" to accompany FGID - with fatigue being the most commonly reported in their cohort. One could interpret this in several ways including taking some inspiration from the name of the author's research group  - the Brain-Gut Research Group - and perhaps even some overlap into other conditions too (see here).

I could also go on about gut bacteria and gut hyperpermeability also mentioned in the paper, but to save me getting too obsessed with these areas, I'll stop right there apart from reiterating that no medical or clinical advice was offered or intended in this blog post.

Music to close: I've linked to this record before but it is a classic so worth again a link... Buddy Holly by Weezer (including The Fonz dancing - what a mover!).

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* Wilder-Smith CH. et al. Fructose and lactose intolerance and malabsorption testing: the relationship with symptoms in functional gastrointestinal disorders. Aliment Pharmacol Ther. 2013 Jun;37(11):1074-83. doi: 10.1111/apt.12306.

** Shepherd SJ. et al. Short-Chain Carbohydrates and Functional Gastrointestinal Disorders. Am J Gastroenterology. 2013; 108: 707-717.

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Wilder-Smith CH, Materna A, Wermelinger C, & Schuler J (2013). Fructose and lactose intolerance and malabsorption testing: the relationship with symptoms in functional gastrointestinal disorders. Alimentary pharmacology & therapeutics, 37 (11), 1074-83 PMID: 23574302