Protein Intake Associated With the Prevalence of Frailty Among Older Adults Consuming Sufficient Energy Intake: The Korea National Health and Nutrition Examination Survey

Results: Combining the three protein sources, the 2 H/ 13 C ratio was numerically lower in older compared to young adults for 7 out of 8 measured indispensable AA (Val, Leu, Ile, Met, Phe, His, Thr, not Lys), ranging from 0.7% for Ile to 13.2% lower in older adults for Leu, an amino acid important for muscle protein synthesis.Therefore, mixed model analysis was performed for Leu and showed significant age effect, with the 2 H/ 13 C ratio being 0.106 lower for older adults (p0.005).This reduction aligns with the hypothesized lower digestibility in older adults, as the 2 H/ 13 C ratio in the meals was expected to be similar between participants.Conclusions: These results provide an indication of lower digestibility in the older adults for some indispensable AA, that should be confirmed by completion of the meal analyses to the principles of the dual-tracer approach.These data indicate at least that the dual-tracer approach can be applied to investigate differences in AA digestibility between young and older adults.Quantifying these differences in digestibility upon ageing provides essential information for product formulation and dietary advice to an older population.