Are oral rehydration solutions optimized for treating diarrhea?

Background: A historical turning point occurred in the treatment of diarrhea when it was discovered that glucose could enhance intestinal sodium and water absorption. Adding glucose to salt water (oral rehydration solution, ORS) more efficiently replaced intestinal water and salt losses. Aim: Provide a novel hypothesis to explain why mainstream use of ORS has been strongly recommended, but weakly adopted. Methods: Traditional (absorptive) and novel (secretory) physiological functions of glucose in an ORS were reviewed. Results: Small amounts of glucose can stimulate both intestinal absorption and secretion. Glucose can exacerbate a net secretory state and may aggravate pathogen-induced diarrhea, particularly for pathogens that affect glucose transport. Conclusion: A hypothesis is made to explain why glucose-based ORS does not appreciably reduce diarrheal stool volume and why modern food science initiatives should focus on ORS formulations that replace water and electrolytes while also reducing stool volume and duration of diarrhea.