The role of zinc on nutritional status, sarcopenia, and frailty in older adults: a scoping review

Background Zinc (Zn) deficiency, malnutrition, sarcopenia, and frailty are prevalent among older adults and are prominent factors contributing to disability and mortality. Objective This scoping review was conducted to aid understanding of the extent and types of research addressing the role of Zn in nutritional status, sarcopenia, and frailty, among older individuals. Method A systematic search was performed in August 2022 of 3 electronic databases (PubMed, Web of Science, and ProQuest) using predefined search terms. The review was conducted referring to the Arksey and O'Malley framework and PRISMA-ScR. Results The search retrieved 16 018 records, and a total of 49 studies were included in this review after the screening. Of those, 30 were based on dietary Zn intake, 18 on tissue Zn levels, and 1 on both. Most studies were based on cross-sectional data from community-dwelling older adults. Studies addressing the associations between Zn status and individual anthropometric and sarcopenia-related variables reported inconsistent results. However, most studies reported inverse associations between malnutrition, frailty, and Zn status. Conclusion There was more consistent evidence of the relationship of Zn status with malnutrition, sarcopenia, and frailty rather than with individual nutritional parameters. Validated screening and assessment tools and criteria and prospective studies are required to elucidate the relationship of Zn with sarcopenia and frailty in the older population.