Antioxidant-rich foods, antioxidant supplements, and sarcopenia in old-young adults ≥55 years old: A systematic review and meta-analysis of observational studies and randomized controlled trials.

BACKGROUND & AIMS: Sarcopenia is a disabling muscular multifactorial disease involving the oxidation process in old-young adults. We aimed to evaluate the relationship between antioxidant-rich foods (A-RF) and sarcopenia (muscle mass, strength, and function) based on observational studies (OS), and to assess the effectiveness of antioxidant interventions in ≥55-year-old adults via randomized controlled trials (RCTs). Moreover, to confirm if the OS results were in accordance with the RCTs results. METHODS: We searched in the MEDLINE®/PubMed, Cochrane Library, and CINAHL databases from 2000 to 2020 about sarcopenia and specific nutrients/foods. The risk of bias was assessed and meta-analyses were performed using the Review Manager program. RESULTS: The systematic review included 28 studies (19 OS, 9 RCTs), whereas the meta-analysis included 4 RCTs. Results of the systematic review of OS revealed that higher A-RF consumption was associated with better sarcopenia outcomes. Results of the RCTs meta-analysis indicated that higher fruit/vegetable consumption, supplementation with magnesium, and vitamin E plus vitamin D and protein significantly reduced the time to complete 5 stands (mean difference; 95% CI; -1.11 s; 1.70, -0.51; p < 0.01). Additionally, including tea catechin supplementation significantly increased handgrip strength (1.02 kg; 0.60, 1.44; p < 0.01). CONCLUSIONS: In sum, A-RF or antioxidant supplementation could be effective tools for sarcopenia, especially improving muscle strength and function. The best interventions according to the meta-analysis of the RCTs were supplementation of vitamin E in combination with vitamin D and protein, magnesium, tea catechins, and increasing fruit and vegetable consumption. REGISTRATION NUMBER: PROSPERO (CRD42020183045).