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 different oral protein loads on energy intake, appetite, antral area, gastric emptying, plasma concentrations of amino acids, hormones (i.e. CCK, PYY, ghrelin, GLP-1, GIP, glucagon and insulin) and glucose, and to determine the relationship between the suppression of appetite and energy intake by protein with ‘intragastric’ and ‘small intestinal’ mechanisms.
Interventions
The participant receives a single 450mL preload per study visit (separated by at least 3 days) in a randomised, crossover fashion of: i) 30 grams Whey Protein Isolate with diet lime cordial flavouring ii) 70 grams Whey Protein Isolate with diet lime cordial flavouring or iii) Water control with diet lime cordial flavouring. All preloads contain 100uL of 13C Octanoic acid to enable measurement of gastric emptying via 13CO2 in the breath.
Gastric emptying rate and intragastric meal distribution a
The participant receives a single 450mL preload per study visit (separated by at least 3 days) in a randomised, crossover fashion of: i) 30 grams Whey Protein Isolate with diet lime cordial flavouring ii) 70 grams Whey Protein Isolate with diet lime cordial flavouring or iii) Water control with diet lime cordial flavouring. All preloads contain 100uL of 13C Octanoic acid to enable measurement of gastric emptying via 13CO2 in the breath. Gastric emptying rate and intragastric meal distribution are determined using 3D ultrasound. Appetite sensation questionnaires in the form of a Visual Analogue Scale (VAS) are measured and blood samples are collected for concentrations of gut hormones, amino acids and glucose. A standard buffet meal is provided at 180 minutes following the preload and the participant has 30 minutes to eat until comfortably full. The buffet meal consists of 300ml orange juice, 600ml water, 375ml iced coffee, 4 slices white bread, 4 slices brown bread, 100g deli leg ham, 100g virginian chicken, 4 slices cheese, 100g tomato, 100g cucumber, 100g lettuce, 2 portions mayonnaise, 2 portions margarine, 1 medium apple, 1 medium banana, 200g chocolate custard, 150g fruit salad, 200g strawberry yoghurt, and a 14g milky way bar. Each volunteer receives one of each of the 3 treatments on each of the 3 study days. Each study visit is separated by no less than 3 days. Each visit lasts approximately 4 hours.
Sponsors
Dr Stijn Soenen
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
65 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Body Mass Index (BMI): 20-30 kg/m2 Weight stable (<5% fluctuation in body weight in previous 3 months).
Exclusion criteria
Significant gastrointestinal symptoms, disease, or surgery. Current gallbladder or pancreatic disease; diabetes mellitus; epilepsy; cardiovasculr 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. Unable to comprehend study protocol.
Outcome results
None listed