(PTFS02-05-26) Improved Fluid Retention With a Sugar-Free, Mineral-Rich Beverage Without Gastrointestinal Distress

Objectives: Rehydration beverages have been based on sugar and sodium since the mid-1960s. This study examined whether a sugar-free mineral-rich beverage enhances post-exercise fluid retention without increasing gastrointestinal symptoms.

Methods: Fifteen young, healthy adults (5 females) completed a 2-h exercise-induced dehydration protocol in the heat to 2% body weight loss, followed by 4 hours of rehydration. In randomized crossover order, participants consumed: sugar-free high sodium (SFHNa; Na: 87 mmol/L; K: 25.6 mmol/L; osmolality: 230 mOsm/kg); sugar-free low sodium (SFLNa; Na: < 1 mmol/L; K: < 1 mmol/L; osmolality: 37 mOsm/kg), or flavored water flavored. Fluids (3% of body weight) were administered during the first hour. Gastrointestinal tolerance was assessed by the Structured Assessment of Gastrointestinal Symptom questionnaire, and a visual analogue scale was used to rate stomach fullness.

Results: SFHNa resulted in lower total urine output (666±294 mL) than SFLNa (1,221±368 mL) and water (1,233±434 mL; P < 0.001). By the end of rehydration, SFHNa showed 32±31% and 28±25% superiority in fluid retention compared to SFLNa and water, respectively, at the individual level. SFHNa yielded higher body weight restoration (1.7±0.7%) than SFLNa (0.8±0.7%) and water (0.7±0.5%; P < 0.001). During rehydration, SFHNa resulted in higher plasma osmolality (287±5 mmol/kg) than SFLNa (285±5 mmol/kg) and water (283±5 mmol/kg, P < 0.001). After drinking 2,107±362 mL of fluids in one hour, stomach fullness was higher with SFHNa (39±56 mm) than with SFLNa (33±50 mm) and water (31±46 mm, P < 0.001), but it remained low (31% of max). There was no effect of beverage type on gastrointestinal symptoms (P>0.05). Subjects reported no problem with constipation (0.1±0.2, 0-4 scale), and gastroesophageal reflux (0.1±0.3, 0-4 scale). No to mild problems were reported with nausea/vomiting (0.8±1.5, 0-4 scale), diarrhea/incontinence (0.4±1.4, 0-4 scale), and epigastric pain (1.6±1.9, 0-4 scale).

Conclusions: A sugar-free, mineral-rich rehydration beverage improved post-exercise fluid retention compared to a low-mineral drink and water without causing moderate to severe gastrointestinal symptoms. This strategy may support effective rehydration when limiting sugar intake is a priority.

Funding Sources: Unrestricted gift from Trace Minerals OpCo LLC