Time of ingestion relative to meal intake determines gastrointestinal responses to a plant sterol-containing yoghurt drink

Plant sterol (PS)-enriched food products are known to reduce plasma cholesterol concentrations by inhibiting the absorption of dietary and biliary cholesterol. The physiological responses induced by food intake in the gastrointestinal tract are all important factors in determining the overall effect of PS. The aim of this study was therefore to assess the effect of timing of consumption of a plant sterol (PS)-containing yoghurt drink relative to meal ingestion on gastric emptying (GE) of the drink and gallbladder (GB) volume. This is a randomized, single-centre, controlled study with crossover design in 12 healthy male volunteers. Three treatments were tested; a 100 mL PS yoghurt drink (labeled with 1,000 mg acetaminophen) was consumed 45 min prior to, during and 45 min after a solid meal. Plasma samples were taken, and gallbladder volumes were measured at baseline and at regular intervals during a 6-h study period. When consumed before the consumption of a meal, the yoghurt drink exhibited fast GE. The solid meal intake caused a significant contraction of the gallbladder. Consumption of the PS drink before the meal had no significant effect on GB volume as compared to baseline and compared to during and after meal consumption. The PS-containing drink, which empties fast from the stomach, does not sufficiently trigger gallbladder contraction without co-ingestion of a solid meal and in consequence does not induce the necessary physiological changes needed to allow PS to exhibit their effect on inhibiting cholesterol absorption.