Intraduodenal guar attenuates the fall in blood pressure induced by glucose in healthy older adults.
OBJECTIVE
Postprandial hypotension occurs frequently in older people and may result in syncope and falls. It has recently been established that the magnitude of the fall in blood pressure is related to the rate at which glucose enters the small intestine. We addressed the hypothesis that the fall in blood pressure induced by an intraduodenal glucose infusion is influenced by the interaction of glucose with the small intestinal absorptive epithelium.


METHODS
Eight healthy older participants (four male, four female, age 70.3 +/- 3.4 years) were studied on two separate occasions, in single-blind, randomized order. Participants received an intraduodenal glucose infusion (3 kcal/min) with or without guar gum (4 g) for 60 minutes (0-60 minutes), followed by 0.9% saline intraduodenally for a further 60 minutes (60-120 minutes). Blood pressure and heart rate were measured every 3 minutes. Levels of blood glucose, plasma insulin, glucagon-like peptide-1 (GLP-1), and glucose-dependant insulinotropic-polypeptide (GIP) were also determined.


RESULTS
Between t = 0 and t = 30 minutes, the magnitude of the fall in systolic blood pressure (p =.03) and increase in heart rate (p =.027) were lower after guar. The blood glucose (p =.009), plasma insulin (p =.027), plasma GLP-1 (p =.018), and GIP (p <.001) responses to intraduodenal glucose were attenuated by guar.


CONCLUSIONS
In healthy older participants, the magnitude of the fall in systolic blood pressure and increase in heart rate induced by intraduodenal glucose are attenuated when the exposure of glucose to the small intestinal mucosa and subsequent glucose absorption is slowed by guar.
O'Donovan
Deirdre
D
Department of Medicine, University of Adelaide, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
Feinle-Bisset
Christine
C
Chong
Chilton
C
Cameron
Alexander
A
Tonkin
Anne
A
Wishart
Judith
J
Horowitz
Michael
M
Jones
Karen Louise
KL
D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D004386:Duodenum; D004562:Electrocardiography; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D005685:Galactans / Q000627:therapeutic use*; D005749:Gastric Inhibitory Polypeptide / Q000097:blood; D005934:Glucagon / Q000097:blood; D052216:Glucagon-Like Peptide 1; D005947:Glucose / Q000008:administration & dosage / Q000009:adverse effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D007328:Insulin / Q000097:blood; D008297:Male; D008351:Mannans / Q000627:therapeutic use*; D010446:Peptide Fragments / Q000097:blood; D053149:Plant Gums; D019518:Postprandial Period / Q000502:physiology*; D011498:Protein Precursors / Q000097:blood; D012016:Reference Values; D016037:Single-Blind Method; D013549:Sweetening Agents / Q000008:administration & dosage*; D013997:Time Factors
D015415:Biomarkers; D001786:Blood Glucose; D005685:Galactans; D007328:Insulin; D008351:Mannans; D010446:Peptide Fragments; D053149:Plant Gums; D011498:Protein Precursors; D013549:Sweetening Agents; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; C007894:guar gum; D005947:Glucose