Browsing by Author "Luscombe-Marsh ND"

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    Dose-Dependent Effects of Randomized Intraduodenal Whey-Protein Loads on Glucose, Gut Hormone, and Amino Acid Concentrations in Healthy Older and Younger Men
    (MDPI (Basel, Switzerland), 12/01/2018) Giezenaar C; Luscombe-Marsh ND; Hutchison AT; Standfield S; Feinle-Bisset C; Horowitz M; Chapman I; Soenen S
    Protein-rich supplements are used widely for the prevention and management of malnutrition in older people. We have reported that healthy older, compared to younger, adults have less suppression of energy intake by whey-protein-effects on appetite-related hormones are unknown. The objective was to determine the effects of intraduodenally administered whey-protein on glucose, gut hormone, and amino acid concentrations, and their relation to subsequent ad libitum energy intake at a buffet meal, in healthy older and younger men. Hydrolyzed whey-protein (30 kcal, 90 kcal, and 180 kcal) and a saline control (~0 kcal) were infused intraduodenally for 60 min in 10 younger (19-29 years, 73 ± 2 kg, 22 ± 1 kg/m²) and 10 older (68-81 years, 79 ± 2 kg, 26 ± 1 kg/m²) healthy men in a randomized, double-blind fashion. Plasma insulin, glucagon, gastric inhibitory peptide (GIP), glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), and amino acid concentrations, but not blood glucose, increased, while ghrelin decreased during the whey-protein infusions. Plasma GIP concentrations were greater in older than younger men. Energy intake correlated positively with plasma ghrelin and negatively with insulin, glucagon, GIP, GLP-1, PYY, and amino acids concentrations (p < 0.05). In conclusion, intraduodenal whey-protein infusions resulted in increased GIP and comparable ghrelin, insulin, glucagon, GIP, GLP-1, PYY, and amino acid responses in healthy older and younger men, which correlated to subsequent energy intake.
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    Effect of gender on the acute effects of whey protein ingestion on energy intake, appetite, gastric emptying and gut hormone responses in healthy young adults
    (Springer Nature Limited, 13/07/2018) Giezenaar C; Luscombe-Marsh ND; Hutchison AT; Lange K; Hausken T; Jones KL; Horowitz M; Chapman I; Soenen S
    BACKGROUND/OBJECTIVES: Protein supplements, usually drinks rich in whey protein, are used widely for weight loss purposes in overweight adults. Information comparing the effects of whey protein on appetite and energy intake in men and women is limited. The objective was to compare the acute effects of whey-protein intake on energy intake, appetite, gastric emptying and gut hormones in healthy young men and women. SUBJECTS/METHODS: Gastric emptying (3D-ultrasonography), blood glucose and plasma insulin, glucagon, ghrelin, cholecystokinin (CCK), gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) concentrations (0-180 min), appetite (visual analogue scales), and ad libitum energy intake from a buffet meal (180-210 min) were determined after ingestion of 30 g (120 kcal) or 70 g (280 kcal) whey protein, or a flavoured-water control drink (~2 kcal) in 8 healthy young men (25 ± 2 y, 72 ± 3 kg, 23 ± 1 kg/m2) and 8 women (23 ± 1 y, 64 ± 2 kg, 24 ± 0.4 kg/m2). RESULTS: There was a protein-load effect on gastric emptying, blood glucose, plasma insulin, glucagon, ghrelin, CCK, GIP and GLP-1 concentrations, and perceptions of hunger, desire to eat and prospective food consumption (P < 0.05). Ad libitum energy intake (average decrease of 206 ± 39 kcal (15 ± 2%) for men and of 46 ± 54 kcal (0 ± 26%) for women for the mean of the intakes after the 30 and 70 g whey-protein loads) and hunger were suppressed more by whey-protein ingestion in men than women (P = 0.046). There was no difference in suppression of energy intake between the 30 and 70 g protein loads (P = 0.75, interaction effect P = 0.19). Consequently, total energy intake (protein drink plus buffet meal) increased more compared to control in women than men (P = 0.010). The drinks emptied more slowly, and plasma glucagon, CCK and GLP-1 increased less after the protein drinks, in women than men (P < 0.05). CONCLUSION: The acute effects of whey protein ingestion on appetite, energy intake, gastric emptying and gut hormone responses are influenced by gender in healthy young adults.
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    Effects of intraduodenal protein on appetite, energy intake, and antropyloroduodenal motility in healthy older compared with young men in a randomized trial.
    (2014-10) Soenen S; Giezenaar C; Hutchison AT; Horowitz M; Chapman I; Luscombe-Marsh ND
    BACKGROUND: Protein-rich supplements are used widely for the prevention and management of undernutrition in older people. The use of protein supplements in older people could, however, be counterproductive by reducing appetite and overall energy intake. OBJECTIVE: The objective was to determine whether aging influences the effects of protein loads, administered directly into the small intestine, on energy intake, antropyloroduodenal motility, and appetite. DESIGN: Intraduodenal infusions (240 mL, 60 min) of saline (0 kcal, control) and protein (hydrolyzed whey) loads of 30, 90, and 180 kcal were followed by an ad libitum buffet meal in 10 young (19-29 y) and 10 healthy older (68-81 y) men. Suppression of energy intake (kcal) at the meal by protein infusion compared with control was calculated. RESULTS: In young subjects, a dose-responsive suppression (±SEM) of energy intake was found at the buffet meal by protein (suppression at 30 kcal: 7 ± 8%, P = 0.189; 90 kcal: 17 ± 8%, P = 0.054; 180 kcal: 33 ± 7%, P = 0.002), whereas suppression was observed only after the 180-kcal load in older subjects (30 kcal: 7 ± 4% increase, P = 0.126; 90 kcal: 6 ± 7% increase, P = 0.291; 180 kcal: 17 ± 6% suppression, P = 0.016). Suppression of energy intake by protein was less in older than in young subjects (P < 0.005). In young subjects, total energy intake (meal + infusion) on the 180-kcal protein-infusion day was lower than that on the control day (P = 0.041), whereas in older subjects it was greater on the 30-kcal (P = 0.033) and 90-kcal (P = 0.016) infusion days. Energy intake was inversely related to isolated pyloric pressure waves (r = -0.32, P = 0.013) and positively related to antral (r = 0.30, P = 0.021) and duodenal (r = 0.35, P = 0.006) pressure waves. Suppression of energy intake by protein was inversely related to the change in isolated pyloric pressure waves (r = -0.35, P = 0.027) and positively related to duodenal pressure waves (r = 0.32, P = 0.044). CONCLUSIONS: Intraduodenal protein suppresses appetite and energy intake less in healthy older than in young adults. In older subjects, intraduodenal protein at low doses increased overall energy intake, which supports the use of protein supplements in undernourished older people. This trial was registered at www.anzctr.org.au as 12612000906853.
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    Effects of randomized whey-protein loads on energy intake, appetite, gastric emptying, and plasma gut-hormone concentrations in older men and women.
    (2017-09) Giezenaar C; Trahair LG; Luscombe-Marsh ND; Hausken T; Standfield S; Jones KL; Lange K; Horowitz M; Chapman I; Soenen S
    Background: Protein- and energy-rich supplements are used widely for the management of malnutrition in the elderly. Information about the effects of protein on energy intake and related gastrointestinal mechanisms and whether these differ between men and women is limited.Objective: We determined the effects of whey protein on energy intake, appetite, gastric emptying, and gut hormones in healthy older men and women.Design: Eight older women and 8 older men [mean ± SEM age: 72 ± 1 y; body mass index (in kg/m2): 25 ± 1] were studied on 3 occasions in which they received protein loads of 30 g (120 kcal) or 70 g (280 kcal) or a flavored water control drink (0 kcal). At regular intervals over 180 min, appetite (visual analog scales), gastric emptying (3-dimensional ultrasonography), and blood glucose and plasma gut-hormone concentrations [insulin, glucagon, ghrelin, cholecystokinin, gastric inhibitory polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and peptide tyrosine tyrosine (PYY)] were measured, and ad libitum energy intake was quantified from a buffet meal (180-210 min; energy intake, appetite, and gastric emptying in the men have been published previously).Results: Energy intake at the buffet meal was ∼80% higher in older men than in older women (P < 0.001). Energy intake was not suppressed by protein compared with the control in men or women (P > 0.05). There was no effect of sex on gastric emptying, appetite, gastrointestinal symptoms, glucose, or gut hormones (P > 0.05). There was a protein load-dependent slowing of gastric emptying, an increase in concentrations of insulin, glucagon, cholecystokinin, GIP, GLP-1, and PYY, and an increase in total energy intake (drink plus meal: 12% increase with 30 g and 32% increase with 70 g; P < 0.001). Energy intake at the buffet meal was inversely related to the stomach volume and area under the curve of hormone concentrations (P < 0.05).Conclusion: In older men and women, whey-protein drinks load-dependently slow gastric emptying and alter gut hormone secretion compared with a control but have no suppressive effect on subsequent ad libitum energy intake. This trial was registered at www.anzctr.org.au as ACTRN12612000941864.