None listed
Conditions
Brief summary
Ageing is associated with a physiological reduction of appetite and energy intake, which has been called the “anorexia of ageing”. Dietary supplementation with liquid protein preparations is now used frequently to increase energy and protein intake in older adults in both institutionalized and community-dwelling populations. Although the latter would appear a logical approach, evidence for success of increased energy intake in older individuals is limited. It is well established that the ingestion of nutrients induce a number of changes in gastrointestinal (GI) function, which are associated with the modulation of appetite and energy intake. These changes include the slowing of gastric emptying, which sustains gastric distension and is associated with proximal gastric relaxation. Urgent investigation is warranted to determine the optimal load of protein that can be incorporated into their diet to assist in sparing muscle mass without reducing their appetite. The study aims to characterise in healthy older individuals, the effect of timing of protein preloads on energy intake, appetite, plasma concentrations of hormones (i.e. CCK, PYY, ghrelin, GLP-1, GIP, glucagon and insulin) and glucose, and studies the relationship between the suppression of appetite and energy intake by protein.
Interventions
16 healthy older subjects (65+ years) will be included in the study. In a randomised intervention order, the subjects will be studied on 5 occasions after an overnight fast. The study visits will be seperated by at least 3 days. Drink ingestion at 0, 60, 120 and 180 min of either whey protein isolate drink P or iso-palatable control drink C (~0kcal): i) P/C/C/C, ii) C/P/C/C, iii) C/C/P/C, iv) C/C/C/P and v) C/C/C/C (control study day). The protein drink will contain 30 g food-grade whey protein
16 healthy older subjects (65+ years) will be included in the study. In a randomised intervention order, the subjects will be studied on 5 occasions after an overnight fast. The study visits will be seperated by at least 3 days. Drink ingestion at 0, 60, 120 and 180 min of either whey protein isolate drink P or iso-palatable control drink C (~0kcal): i) P/C/C/C, ii) C/P/C/C, iii) C/C/P/C, iv) C/C/C/P and v) C/C/C/C (control study day). The protein drink will contain 30 g food-grade whey protein isolate powder dissolved in 70 mL distilled water and 50 mL low-calorie lime cordial (Bickfords diet lime cordial). The control drink will contain 90 mL distilled water and 40 mL low calorie lime cordial. The drinks will be equivolaemic (130 mL), and matched for taste. A baseline venous blood sample will be taken and the subject will complete a visual analogue scale (VAS) to assess appetite-related sensations. VAS questionnaires will be collected at t=-2 min (baseline) and t= 2, 27, 57, 62, 87, 117, 122, 147, 177, 182 and 212 min. Blood samples (11.4 mL each) will be collected at 7 time points t = -5 min (baseline) and t = 25, 55, 85, 115, 145, and 175 min). Blood pressure and heart rate will be measured prior to the drink (baseline) and at 3 minute intervals from t = 0 - 180 minutes and after the buffet meal t = 210 min. At t = 180 min, the intravenous cannula will be removed and subjects will be presented with a cold, buffet-style meal. Subjects will be allowed 30 min to freely consume food until they feel comfortably full. The weight of the foods will be recorded before and after it is offered to the subjects and energy intake and macronutrient composition calculated subsequently using commercially available software.
Sponsors
Stijn Soenen
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
65 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Body Mass Index (BMI): 22-30 kg/m2 Weight stable (<5% fluctuation in body weight in previous 3 months) Age >65
Exclusion criteria
Significant gastrointestinal symptoms, disease, or surgery. Current gallbladder or pancreatic disease; diabetes mellitus; epilepsy; cardiovascular or respiratory diseases; any other illnesses as assessed by the investigator (including chronic illnesses not explicitly listed above). Impaired cognitive function. Depression. Use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may effect gastrointestinal function or appetite. Lactose intolerant or other food allergies; intolerance or allergy to paracetomol. Individuals with low ferritin levels or who have donated blood in the 12 weeks prior to taking part in the study. Current intake of >2 standard drinks on >5 days per week. Current smokers of cigarettes/cigars/marijuana. Current intake of any illicit substance. Experience claustrophobia in confined spaces. Unable to comprehend study protocol.
Outcome results
None listed