High-Protein Nutritional Guidance Prevents the Progression of Sarcopenia in Super-Elderly Individuals with Type 2 Diabetes

Background: Sarcopenia is a major cause of physical decline in older adults with type 2 diabetes (T2DM). Nutritional interven-tions, especially high-protein diets, are clinically recommended, but their long-term effectiveness and tolerability in very elderly diabetes patients remain unclear. Objective: We investigated whether an 18-month dietary intervention improves muscle mass and strength in patients aged ≥75 years with T2DM, and whether serum amino acids (AAs) and hormonal profiles reflect these changes. Methods: We enrolled 44 subjects aged ≥75 years with T2DM. Nutritional counseling was provided at baseline, 6, 12, and 18 months. Skeletal muscle index (SMI), grip strength, and gait speed as well as fasting plasma hormones and AAs were assessed at each visit. Sex-normalized SMI (nSMI) and grip strength (nGrip) were calculated, and multiple linear regression analysis was per-formed. Results: SMI improved at 6 and 12 months; gait speed improved at 6 months. Grip strength showed a significant increase at 12 months. Changes in ΔnSMI were independently associated with Δglucagon (positive) and ΔC-peptide (CPR)(negative), while Δn-Grip was inversely associated with Δglucagon at 6 months. Increases in two AAs were linked to reduced ΔnSMI and increases in 16 AAs were linked to reduced ΔnGrip. Renal and hepatic function remained stable over 18 months. Conclusion: Long-term dietary intervention is effective for improving sarcopenia-related outcomes in very elderly patients with T2DM while maintaining general metabolic stability. Early changes in glucagon, CPR, and AAs levels may contribute to these improvements.