Digestibility of High-Protein Drinks in Seniors

Brief name: Cross-over nutrition study to evaluate post-ingestion amino acid release and metabolism of two high-protein drinks with a comparator drink. Intervention The drinks to be evaluated, including comparator drink, are high-protein drinks made from plant and animal food proteins routinely used in food products, containing 11.2% protein, 5% fat and 12% carbohydrate. Participants consume 250-275 ml of drink. Participants consume a provided meal before 10 pm the night before the session, remaining in a fasted state after the evening meal and take a urine sample on rising. On arrival at the research unit (7.30-9.00 am) they are cannulated in an elbow or forearm vein, and consume one of the high-protein drinks. They receive 250 ml water every hour. Blood samples are collected at intervals for plasma amino acid and metabolomics analysis. Participants provide urine at intervals for urine metabolomics analysis. Participants regularly rate satiety and thirst. Those designing the trial and the participant contact have completed the Massey University training module on ethical conduct and standards for Human and Animal studies. Cannulation insertion and maintenance is provided by a named person with professional experience of cannulation and phlebotomy (nurse or paramedic). The intervention is delivered over 3 x 6 hour sessions, one of which includes a comparator drink, over a period of up to 4 weeks. The minimum washout period is 2 days between treatments. The cannulation and urine collection take place either at the Massey Human Nutrition Unit (Massey University Turitea campus, Palmerston North) or at the Massey Sports and Exercise Science Laboratory (Massey University Wellington campus, Wellington).