Description:
<jats:sec><jats:title>Background and aim</jats:title><jats:p>Inadequacies of micronutrients with antioxidant‐properties are common among older adults and have been associated with sarcopenia and with impaired muscle health. The aim of this study was two‐fold: 1) to investigate if low levels of micronutrients with antioxidant‐properties (AOX) had a negative impact on muscle function in mature mice and 2) to study if nutritional interventions with AOX and/or leucine‐enriched whey protein could improve it.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>18‐months‐old mice were fed an AOX‐deficient diet (vitamin A/E 600/5 IU/kg, Se 0.04, Zn 2.5 mg/kg=LOWOX) or a casein‐based AIN‐93‐M control diet (CTRL) for 7 months. During the last 3 months, the LOWOX mice were randomized to 4 nutritional interventions: a) continued LOWOX, b) supplementation with vitamin A/E 8000/600 IU/kg, Se 2, Zn 35 mg/kg (AOX), c) substitution of casein protein with leucine‐enriched whey protein (PROT) or d) a combination of both (TOTAL). Parameters of sarcopenia (muscle mass, grip strength and <jats:italic>ex‐vivo</jats:italic> muscle function), muscle fatigue (<jats:italic>ex‐vivo</jats:italic> exercise‐protocol), general oxidative status (liver malondialdehyde (MDA)) and muscle mitochondrial dynamics were measured by RT‐PCR.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>After 7 months LOWOX mice showed lower muscle strength and more muscle fatigue compared to CTRL. AOX mice displayed improved liver MDA, improved grip strength, less muscle fatigue and improved mitochondrial dynamics compared to LOWOX mice (P<0.05). Compared to LOWOX mice, the PROT group showed higher muscle power and grip strength, and less muscle fatigue (P<0.05). The TOTAL group showed the combined effects of both interventions compared to the LOWOX group (P<0.05).</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>AOX‐deficiency has a negative impact on muscle strength and fatigue, possibly due to impaired mitochondrial dynamics. Supplementation of micronutrients with antioxidant properties in combination with a diet containing leucine‐enriched whey protein is an effective and optimal strategy to improve general state of fitness and muscle quality in aged antioxidant deficient mice. These findings are also relevant for human aging, especially the elderly and frail or sarcopenic population that often suffers from antioxidant deficiencies, increased oxidative stress and loss of muscle quality.</jats:p></jats:sec>