# Protein Intake and Muscle Function in Older Adults

Higher protein intake can improve selected muscle outcomes in some nutritionally vulnerable older adults; adequate-intake cohorts often gain little, and lean-mass changes do not establish stronger or more functional muscle.

The registered primary-subclaim rule selects SC3. A quantified above-RDA protein contrast produced a modest functional benefit in a baseline malnourished, pre-frail or frail population. Controlled feeding and supplementation nulls in other defined populations limit generalization, supporting Ε with Moderate confidence. Acute synthesis and lean mass do not establish universal strength preservation. Weakest-link returns Γ; primary-subclaim and scope-matched return Ε.

Age≥60, baseline intake, validated malnutrition/frailty, energy deficit, achievedprotein separation, exercise, formulation andrenalstate are assessed before outcomes. Positive malnourished-dose and null stablefeeding/training/sarcopenia contexts map a heterogeneous boundary. Frail participants withnull outcomes remaininscope; a responder-defined nutritionaldeficit isforbidden. Mixed50–79year reports andsub8week rehab are boundaryevidence ratherthan a cleanprimary8–52week≥60 clinicalcrossing.