Protein-based oral rehydration solutions for patients with an ileostomy: A randomised, double-blinded crossover study

Patients with an ileostomy are at increased risk of dehydration and sodium depletion. Treatments recommended may include oral rehydration solutions (ORS). We aimed to investigate if protein type or protein hydrolysation affects absorption from iso-osmolar ORS in patients with an ileostomy. This was a randomised, double-blinded, active comparator-controlled 3 × 3 crossover intervention study. We developed three protein-based ORS with whey protein isolate, caseinate or whey protein hydrolysate. The solutions contained 40–48 g protein/L, 34–45 mmol sodium/L and had an osmolality of 248–270 mOsm/kg. The patients ingested 500 mL/d. The study consisted of three 4-week periods with a >2-week washout between each intervention. The primary outcome was wet-weight ileostomy output. Ileostomy output and urine were collected for a 24-h period before and after each intervention. Additionally, blood sampling, dietary records, muscle-strength tests, bioimpedance analyses, questionnaires and psychometric tests were conducted. We included 14 patients, of whom 13 completed at least one intervention. Ten patients completed all three interventions. Wet-weight ileostomy output did not change following either of the three interventions and did not differ between interventions (p = 0.38). A cluster of statistically significant improvements related to absorption was observed following the intake of whey protein isolate ORS, including decreased faecal losses of energy (−365 kJ/d, 95% confidence interval (CI), −643 to −87, p = 0.012), potassium (−7.8 mmol/L, 95%CI, −12.0 to −3.6, p = 0.001), magnesium (−4.0 mmol/L, 95%CI, −7.4 to −0.7, p = 0.020), improved plasma aldosterone (−4674 pmol/L 95%CI, −8536 to −812, p = 0.019), estimated glomerular filtration rate (eGFR) (2.8 mL/min/1.73 m2, 95%CI, 0.3 to 5.4, p = 0.03) and CO2 (1.7 mmol/L 95%CI, 0.1 to 3.3, p = 0.04). Ingestion of 500 mL/d of iso-osmolar solutions containing either whey protein isolate, caseinate or whey protein hydrolysate for four weeks resulted in unchanged and comparable ileostomy outputs in patients with an ileostomy. Following whey protein isolate ORS, we observed discrete improvements in a series of absorption proxies in both faeces and blood, indicating increased absorption. The protein-based ORS were safe and well-tolerated. Treatments should be tailored to each patient, and future studies are warranted to explore treatment-effect heterogeneity and whether different compositions or doses of ORS can improve absor