D‐galactose might mediate some of the skeletal muscle hypertrophy‐promoting effects of milk—A nutrient to consider for sarcopenia?

Abstract

AbstractSarcopenia is a process of progressive aging‐associated loss of skeletal muscle mass (SMM) recognized as a serious global health issue contributing to frailty and increased all‐cause mortality. Exercise and nutritional interventions (particularly intake of dairy products and milk) demonstrate good efficacy, safety, and broad applicability. Here, we propose that at least some of the well‐documented favorable effects of milk and milk‐derived protein supplements on SMM might be mediated by D‐galactose, a monosaccharide present in large quantities in milk in the form of disaccharide lactose (milk sugar). We suggest that ingestion of dairy products results in exposure to D‐galactose in concentrations metabolized primarily via the Leloir pathway with the potential to (i) promote anabolic signaling via maintenance of growth factor (e.g., insulin‐like growth factor 1 [IGF‐1]) receptor mature glycosylation patterns; and (ii) provide extracellular (liver glycogen) and intracellular substrates for short (muscle glycolysis) and long‐term (muscle glycogen, intramyocellular lipids) energy availability. Additionally, D‐galactose might optimize the metabolic function of skeletal muscles by increasing mitochondrial content and stimulating glucose and fatty acid utilization. The proposed potential of D‐galactose to promote the accretion of SMM is discussed in the context of its therapeutic potential in sarcopenia.