Aging skeletal muscle displays an altered
iron status that may promote oxidative stress and
sarcopenia. A diet containing low
iron (LI) could reduce muscle
iron status and attenuate age-related
muscle atrophy. Supplemental
branched-chain amino acids (BCAA) may also alleviate
sarcopenia by promoting
muscle protein synthesis and
iron status improvement. This study examined individual and combined effects of LI and BCAA diets on anabolic signaling and
iron status in skeletal muscle of aging rats. Twenty-nine-month-old male Fisher 344 × Brown Norway rats consumed the following control-base diets: control + regular
iron (35 mg
iron/kg) (CR; n = 11); control + LI (∼6 mg
iron/kg) (CL; n = 11); 2×BCAA + regular
iron (BR; n = 10); and 2×BCAA + LI (BL; n = 12) for 12 weeks. Although LI and/or 2×BCAA did not affect plantaris muscle mass, 2×BCAA groups showed lower muscle
iron content than did CR and CL groups (P < 0.05). p70
ribosomal protein S6 kinase phosphorylation was greater in 2×BCAA and LI animals compared with CR animals (P < 0.05). Interactions between
IRON and BCAA were observed for
proteins indicative of mitochondrial biogenesis (
peroxisome proliferator-activated receptor gamma coactivator 1 alpha) and oxidative capacity (
cytochrome c oxidase subunit 2 and
citrate synthase) (P < 0.05) wherein the combined diet (BL) negated potential benefits of individual diets.
Antioxidant capacity,
superoxide dismutase activity, and oxidative injury (3-
nitrotyrosine,
protein carbonyls, and 4-hydroxynonenal) were similar between groups. In conclusion, 12 weeks of LI and 2×BCAA diets showed significant impacts on increasing anabolic signaling as well as ameliorating
iron status; however, these interventions did not affect muscle mass.