SLC5A2 and malnutrition: In addition to the primary age-related sarcopenia, one can also distinguish secondary sarcopenia, which can be related to a lack of activity, malnutrition, diseases (e.g., osteoporosis, rheumatoid arthritis, insulin resistance, liver diseases) and drugs (e.g., statins, sulfonylureas, SGLT2 (sodium-glucose cotransporter 2), inhibitors, steroids, chloroquine, colchicine, nucleoside analogues, loop diuretics, androgen deprivation therapy, D-penicillamine, antineoplastic drugs, immune checkpoint inhibitors) [5,6,7].