Co-designed, personalised protein supplementation with whole-food dairy products in a randomised controlled trial: An investigation of success and acceptability in ≥80 years old community-dwelling adults

Background & aims: Protein malnutrition is associated with loss of muscle mass and physical function in older adults, and specific tailored nutritional interventions may be required. This two-phased randomised controlled trial aimed at evaluating the success of 16-week co-designed personalised protein supplementation intervention with whole-food dairy products in community-dwelling adults 80+ years. Methods: Participants, recruited through a nationally regulated preventive service, were screened for protein malnutrition, with personalised guidance provided if below the cut-point of 1.0 g/kg/day (phase 1: 1-month optimization period). All eligible participants (≥1.0 g/kg/day) were randomly assigned to i) protein supplementation + power training, ii) protein supplementation-only, or iii) control. Protein supplementation included co-design of a supplementation plan with whole-food dairy products to supplement habitual diet (phase 2). Success was evaluated from changes in protein intake (mean (10; 90 percentiles) and ≥1.35 g/kg/day cut-point. Results: Of the 92 participants entering the study, 55.4 % were protein malnourished with 56,9 % reaching eligibility following personal guidance. A total of 38 participants were randomised to phase 2. All receiving protein supplementation increased protein intake (0.24 (0.01; 0.63) g/kg/day) compared to 16.7 % in the control group (−0.19 (−0.35;-0.07)). However, only 47 % of participants in the supplementation groups reached cut-point success criteria (1.35 g/kg/day). Conclusion: Co-designed personalised protein supplementation with whole-food dairy products was successful to increase protein intake in adults 80+ year. Nevertheless, reaching high intake was challenging. Individual nutritional guidance by a nutritional specialist may result in higher level of protein intake among most older adults with habitual low levels of protein intake.