The effect of two weeks ingestion of a bitter tastant mixture on energy intake in overweight females.

Triggering of gastro-intestinal bitter taste receptors might have implications for appetite and food intake, but the evidence in humans is mixed and limited to acute studies. We previously reported that 15-days consumption of drinks with purified Hoodia gordonii extract and its taste-matched control both produced similar, significant energy intake (EI) reductions in females in an in-patient setting, with no significant differences between treatments. In that study the control was matched to Hoodia flavour and bitterness using Raisin Flavour (RF), Sucrose Octa Acetate (SOA) and Quassia Extract (QE). As triggering of gastrointestinal bitter receptors might have produced shared effects on EI, our objective here was to assess the effects of sustained exposure to capsules containing the same bitter RF + SOA + QE mix itself on EI, compared to a non-bitter placebo. In this randomized, double-blind study, sixty slightly overweight women in parallel groups consumed twice-daily capsules without (placebo) or with the tastant mixture (0.88 mg SOA, 0.088 mg QE, 0.22 mg RF) on days 1-14. On day 0 all subjects received placebo capsules at 0800 and 1600, ad libitum meals at 0900, 1300, 1700, and snacks after 1900. On day 14 these test procedures were repeated. Changes in EI on days 14 versus 0 between treatment groups were assessed using ANCOVA. Total EI differences on days 14 versus 0 were not significant (mean active-placebo treatment difference -109 kcal, SE 71, P = 0.13), nor was this significant when analyzed separately for each meal within the test day. Body weight changes were negligible. In conclusion, sustained exposure to these encapsulated bitter tastants did not significantly affect EI in overweight females.