Abstract
Glycomacropeptide (GMP) has a unique amino acid profile which may make less satiating than other dietary proteins. This study assessed the feasibility and likely acceptability of a leucine-enriched GMP drink and determined appetite response in older adults (OA). Thirteen OA (11f; 70±4 years) were recruited for sensory assessments of a leucine-enriched GMP drink when mixed with water and with fruit smoothie, compared with whey protein isolate (WHEY). Participants also partook in a single focus group exploring acceptability to protein and supplementation. Separately, a counterbalanced, double-blind study with twelve OA (8f; 69±3 years) was conducted to determine appetite and gut hormone responses. Fasting subjective appetite was recorded using visual analogue scales and a fasted venous blood sample was collected (to measures acyl-ghrelin, PYY, GLP-1, and CCK) before participants consumed either: GMP protein (27g + 3g leucine, 350mL water), WHEY (30g, 350mL water), or water. Participants rested for 240minutes, with appetite measures and blood sampling throughout. An ad libitum pasta-based meal was then consumed. Sensory testing revealed low pleasantness rating for GMP in water vs. WHEY (16±14 vs 31±24, p=0.016). GMP addition to smoothie reduced pleasantness (26±21 vs. 61±29, p=0.009) and worsened the aroma (46±15 vs. 69±28, p=0.014). The focus group revealed uncertainty of protein needs and a scepticism of supplements, with preference for food. Gut hormone response did not differ between GMP and WHEY (nAUC for all gut hormones p>0.05). There was no difference between conditions for lunch ad libitum intake (549±171 kcal, 512±238 kcal, 460±199 kcal for GMP, WHEY, and water, p=0.175), or for subjective appetite response. Leucine-enriched GMP was not less satiating than WHEY, and low palatability and scepticism of supplements question the likely acceptability of GMP supplementation. Providing trusted nutritional advice and food enrichment/fortification may be preferred strategies for increasing protein intake in OA.
Original language | English |
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Article number | 107509 |
Number of pages | 11 |
Journal | Appetite |
Volume | 200 |
Early online date | 23 May 2024 |
DOIs | |
Publication status | E-pub ahead of print - 23 May 2024 |
Bibliographical note
We would like express huge gratitude to our participants for taking part, and for making data collection such an enjoyable experience for the research team. We would like to thank our students Vicky Catterall, Beth Minion, Joe Ashworth, Monty Hardcastle, and Anna Brooks for supporting data collection. We also thank Agropur Ingredients (Eden Prairie, MN, USA) for providing GMP.Data Availability Statement
Data will be made available on request.Keywords
- Hunger
- satiety
- energy intake
- anorexia of ageing
- undernutrition
- ageing