Sorbitol

What is it?

Sorbitol is a sugar alcohol — a polyol — used as a sweetener in sugar-free gum, sweets and diabetic products, and present naturally in stone fruit: apples, pears, peaches, plums, prunes. It is poorly absorbed in the small intestine, draws water into the colon and is fermented there, which gives osmotic diarrhoea and gas.

How poorly absorbed is "poorly"

Yao (2014) put a number on it. Challenged with 10 g in a randomised, double-blinded, placebo-controlled test, only 33 per cent of healthy people absorbed sorbitol completely, and 40 per cent of those with irritable bowel syndrome. Mannitol reversed it — 80 per cent of the IBS group absorbed that one completely against 43 per cent of the healthy — so the two polyols on this axis do not behave alike, and being sensitive to one does not predict the other. Its composition tables are in the paper rather than the abstract, so it names which kinds of food carry which polyol without giving a figure for any single one.

Polyols compound, which a food list cannot show

Lenhart (2017) screened 1,823 articles and kept 79. Malabsorption is dose-dependent in healthy people, and it INCREASES WHEN POLYOLS ARE EATEN IN COMBINATION — a pear and a sugar-free mint are not two separate small doses, they compound. The same review is honest about what is unsettled: studies in IBS conflict on whether malabsorption differs there at all, and at moderate doses these molecules shift the microbiome toward bifidobacteria and may act as prebiotics. It reviews effects rather than composition, so it carries no polyol content for any food and no threshold in grams.

Where it has actually been measured

Ma (2014) separated sorbitol alongside fructose, glucose and sucrose in four fruits — peach, apple, watermelon and cherry — and found sorbitol from 8.70 to 19.13 mg/g. Four fruits, and a method paper rather than a composition table. Mikulic-Petkovsek (2012) analysed sugars in 25 wild or cultivated berry species and detected and quantified sorbitol in chokeberry, rowanberry and eastern shadbush — which tells you which berries carry it at all, not how much, since the abstract publishes no per-species figure.

One polyol is not another

Storey (2007) gave 64 adults single oral boluses in water against a 45 g sucrose control. Xylitol at 50 g significantly raised nausea, bloating, borborygmi, colic and watery stools; 35 g did not. Erythritol was better tolerated across the doses tested. That is two polyols and a sucrose control and nothing else — no sorbitol, no mannitol, no maltitol — so it cannot rank xylitol against those, and single boluses in water are not the same as a polyol eaten in food.

Source: Yao C.K. et al., J Hum Nutr Diet 27 Suppl. 2 (2014) 263-275, for the measured absorption of a 10 g sorbitol and mannitol challenge — its composition tables are in the paper and not the abstract; Lenhart A. & Chey W.D., Adv Nutr 8 (2017) 587-596, a systematic review of 79 studies, for malabsorption being dose-dependent and compounding in combination — effects and not composition; Ma C. et al. (2014), for sorbitol at 8.70-19.13 mg/g in four fruits; Mikulic-Petkovsek M. et al. (2012), for sorbitol detected in chokeberry, rowanberry and eastern shadbush among 25 berry species, with no per-species figure; Storey D. et al. (2007), for xylitol and erythritol tolerance against a 45 g sucrose control — two polyols only

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