Saccharin increases perception of bladder filling in a forced diuresis experiment

AIMS: To study bladder sensation during a forced diuresis protocol and to assess differences in sensation perceived by different ethnic groups and after drinking artificially sweetened water. METHODS: Female Caucasian and south Indian Asian volunteers performed the diuresis protocol drinking water, or water sweetened with saccharin (5 mg/kg body weight). Participants recorded filling sensation every 5 min while drinking 250-350 mL/15 min. They were asked to record the strongest sensation before voiding as maximum sensation, before voiding. The void was measured and sensation immediately recorded as minimum. The process was repeated. Voided volume and time required to achieve maximum sensation during cycle 2 were compared by water and sweetener, ethnic group, and age. RESULTS: Twenty Asian and 20 Caucasian volunteers participated. No differences in maximum voided volume or diuresis rate was seen by ethnicity. Median diuresis with sweetener was 16.7 mL/min (8.6-35) compared to 13.2 (7.1-25) with water (P = 0.008), a difference accounted for by 16 women with >5 mL/min difference in diuresis rate. These were excluded to leave 24 women with similar diuresis rates with both sweetener and water (14.8 mL/min (8.6-28.0) and 13.2 mL/min (7.1-25.0). In these women, time to achieve maximum sensation was lower with sweetener than water: 37.5 min (20-85) versus 50.0 min (20-80), P = 0.002, with no difference in voided volume. CONCLUSIONS: Water sweetened with saccharin produced an increased diuresis rate in some women. After controlling for this, time to recording maximum sensation was decreased with sweetened water, suggesting saccharin has an effect upon perceived sensation.