OBJECTIVE: To determine whether slowing of gastric emptying and glucose abs
orption with guar gum would reduce the fall in blood pressure after an oral
glucose load in older subjects.
DESIGN: A randomized, experimental, cross-over study.
SETTING: Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide,
SA, Australia.
PARTICIPANTS: Ten healthy subjects, age 67 to 78.
MEASUREMENTS: Simultaneous measurements of gastric emptying, blood pressure
, blood glucose, serum insulin, and oral glucose absorption (3-O-methyl-D-g
lucose [3-OMG]) on two occasions after ingestion of 300 mL water containing
50 g glucose and 30 mL lemon juice, 3 g 3-OMG labeled with Tc-99m-sulphur
colloid; with or without 9 g guar gum. Blood pressure and gastric emptying
were monitored for 180 minutes.
RESULTS: The magnitude of the falls in systolic (P = .02), diastolic (P < .
05), and mean arterial (P = .05) blood pressure were less, and gastric empt
ying slower (P < .05), after guar. Blood glucose, insulin, and 3-OMG concen
trations were reduced (P < .001 for all) by guar. 3-OMG con centrations wer
e inversely related to the intragastric retention of glucose (r = -0.72, P
= .02) and blood pressure was inversely related to 3-OMG (r = -0.64, P < .0
5) after the drink without guar. The blood glucose concentration was relate
d to 3-OMG (r > 0.64, P < .05).
CONCLUSION: Guar gum reduces the magnitude of the fall in blood pressure af
ter oral glucose. Slowing of gastric emptying and glucose absorption may re
present a novel approach to the treatment of postprandial hypotension.