Item – Theses Canada

​
OCLC number
54972276
Link(s) to full text
LAC copy
LAC copy
Author
Kaplan, Randall Jeffrey,1972-
Title
Influence of dietary protein, carbohydrate, and fat on cognitive performance and appetite in healthy elderly persons.
Degree
Ph. D. -- University of Toronto, 2002
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2003]
Description
3 microfiches.
Notes
Includes bibliographical references.
Abstract
The primary hypothesis of this thesis was that energy ingestion from carbohydrates (glucose, potato, and barley), protein (whey), and fat (safflower oil) enhances cognitive performance compared with a placebo in healthy elderly persons. The secondary hypothesis was that carbohydrates influence satiety differently from each other, and protein (whey) induces higher satiety than carbohydrate (glucose) or fat (safflower oil) in this population. Experiment 1 examined the effects of 50g of carbohydrate as glucose, potatoes or barley, compared with a non-energy placebo on cognition, subjective appetite, and food intake over 120min in healthy subjects (aged 60-82y) after an overnight fast. Experiment 2 examined the effects of isoenergetic, equal volume drinks of pure whey protein, glucose, and safflower oil compared with a placebo on the same variables and age group as experiment 1, over 90min. The relationship between glucose regulation and these variables was determined. Experiment 1 showed that poor baseline memory was associated with poor glucose regulation, but this was not reproduced in experiment 2. All carbohydrates improved memory in subjects with poorer glucose regulation and baseline memories independently of plasma glucose concentration in experiment 1. Glucose, whey protein, and safflower oil improved memory in experiment 2 independently of plasma glucose concentration, however, the effects were not related to glucose regulation. Each macronutrient also had unique effects on cognition. In both experiments, the strongest effects occurred 15min after ingestion and on declarative memory. The appetite measures showed that carbohydrates had different effects on subjective appetite and food intake but glycaemic index (GI) did not predict these effects (experiment 1). Experiment 2 showed that whey protein and safflower oil induced higher subjective satiety than placebo, but only whey protein decreased food intake. These findings showed that glucose regulation may be associated with cognition in healthy elderly subjects, that energy ingestion can improve memory independently of plasma glucose concentration, and that each macronutrient exerts unique effects on cognition. These findings also showed that the elderly respond to physiologic appetite signals, that GI does not predict satiety, and that protein (whey) decreases food intake more than carbohydrate (glucose) or fat (safflower oil) in this population.
ISBN
0612692159
9780612692152