Abstract
OBJECTIVES: Chronic excessive intake of ultra-processed foods (UPFs) has been linked to various metabolic conditions; however, its impact on skeletal muscle mass and function in older adults remains unclear. Therefore, we conducted this study to examine the association between UPF intake and age-related muscle outcomes, including frailty, sarcopenia, low muscle mass (LMM), and/or low muscle strength (LMS). METHODS: A systematic search was conducted in ISI Web of Science, LILACS, PubMed/MEDLINE, and Scopus without restrictions up to November 1, 2024. Relative risks (RRs) and 95% confidence intervals (CIs) were pooled using a random-effects model. Study quality and the presence of publication bias were assessed using the Newcastle-Ottawa Scale, Egger's regression asymmetry test, and Begg's rank correlation test. RESULTS: Data from 29 studies were included. Cohort studies showed that higher UPF intake was significantly associated with an increased risk of frailty (RR = 1.40; 95% CI 1.25-1.58; I(2) = 83.0%; p < 0.001; n = 11), but not with LMS. In contrast, cross-sectional studies indicated that higher UPF intake was significantly associated with an increased risk of LMS (RR = 1.13; 95% CI 1.06-1.20; I(2) = 0.0%; p < 0.001; n = 5), but not with frailty, sarcopenia, or LMM. Furthermore, a 100 g increase in UPF intake was associated with a 3% higher risk of frailty (RR = 1.03; 95% CI 1.01-1.06; I(2) = 85.1%; p = 0.016; n = 5). Non-linear dose-response analysis showed a positive linear association between UPF intake and frailty risk (P_non-linearity = 0.807; P_dose-response < 0.001; n = 5). CONCLUSION: Higher UPF intake was associated with an increased risk of frailty in cohort studies and with low muscle strength in cross-sectional studies. These findings suggest that regular consumption of UPFs may negatively affect muscle health, potentially impairing quality of life and independence in older adults.