Nutritional Care of the Frail Patient with Heart Failure: Evidence, Uncertainties and Research Priorities

Frailty is highly prevalent in patients with heart failure (HF) and frequently coexists with malnutrition, sarcopenia, cachexia, and obesity, creating substantial challenges for nutritional assessment and management. These conditions overlap clinically but represent distinct biological phenotypes and should not be treated as interchangeable constructs. This narrative review critically synthesizes current evidence on nutritional care in patients with HF and frailty, focusing on nutritional assessment, energy and protein requirements, areas of alignment and conflict between HF- and frailty-oriented recommendations, and the effects of nutritional interventions on frailty-related outcomes. Nutritional assessment should be multidimensional, as congestion, inflammation, altered body composition, and renal dysfunction may limit the interpretability of body weight, BMI, biochemical indices, and screening tools. Current recommendations for energy and protein intake remain largely extrapolated from geriatric, multimorbidity, renal, or general HF populations, and no universally validated targets exist for frail patients with HF. Dietary management therefore requires balancing potentially competing priorities, including congestion control, preservation of muscle mass and function, adequate nutrient intake, renal limitations, and, in obesity-related HF, intentional fat loss without excessive loss of lean tissue. Available interventional evidence suggests that individualized nutritional support may improve nutritional status and selected functional outcomes, but effects on frailty as an integrated syndrome remain uncertain. Overall, nutritional care in HF with frailty should move towards phenotype-directed, multidisciplinary strategies integrating nutrition, physical activity, rehabilitation, and longitudinal assessment. Future trials should standardize frailty definitions, clinically relevant outcomes, and nutrition-related targets.