Jéssica Martínez Rodríguez

Background: Low-grade chronic dehydration may have mid-to-long-term effects on muscle function. Objectives: To assess hydration status and intracellular hydration of right-leg lean mass for a community-dwelling aged population, and to assess the relationship with thigh muscle function decline. Methods: Design: observational prospective study of individuals aged ≥70 years followed up for 12 months. Measures: body composition and hydration status were assessed by bioelectrical impedance analysis (BIA) and isokinetic testing was used to measure right-knee flexion and extension strength, work, and power. The intracellular water/fat free-mass ratio (ICW/FFM) was considered the main study factor. Results: Of 117 recruited individuals (75.0 ± 4.1 years, 50.4% women), 52 were available for 12-month follow-up. After adjusting for age, sex, and number of medications, right-leg ICW/FFM showed an independent effect on 12-month increases in right-leg extension strength (beta = 1120 N, p = 0.078), work (beta = 2356 J, p = 0.017), and power (beta = 1921 W, p = 0.021), and in flexion strength (beta = 1610 N, p = 0.134), work (beta = 6270 J, p = 0.008), and power (beta = 5183 W, p = 0.003). Conclusions: BIA indicators of poor lower-limb muscle hydration are correlated with a decline in certain muscle function parameters in the same limb, suggesting that dehydration may affect muscle function in aged populations.

Background: The physiopathology of sarcopenia is still not completely understood. Aim: To assess the relationship between dehydration and skeletal muscle catabolism, muscle mass, and sarcopenia in an aged population. Methods: Observational cross-sectional study of community-dwelling subjects aged 70 years and older. Dehydration was assessed by plasma osmolarity; bioimpedance analysis (BIA) was used to assess body composition and water content; sarcopenia was established according to the EWGSOP-2 criteria; and 3-methyl-histidine (3MH) was used as an indicator of muscle catabolism. Results: 190 participants were recruited (77.4 years; 51.6% women). In total, 22.6% and 20.5% presented plasma osmolarity of 295–300 mOsm/L and >300 mOsm/L, respectively. Age was correlated with plasma osmolarity (r_s = 0.439; p < 0.001). Plasma osmolarity was correlated with 3MH (r_s = 0.360; p < 0.001) and showed an effect on 3MH levels, with an adjusted (by age, sex, and number of medications) beta of 0.283 (p < 0.001). BIA water content indicators showed no correlation with 3MH. Lower in sarcopenic compared to non-sarcopenic subjects were the intracellular water percentage (60.3 vs. 61.2%; p = 0.004) and intracellular water/free-fat mass ratio (44.3 vs. 45.0; p = 0.004). Conclusions: Dehydration is a highly prevalent clinical condition in aged populations, increases with age, and is associated with muscle catabolism but not sarcopenia.

Revista oficial de la Sociedad Española de Nutrición Parenteral y de la Sociedad Española de Nutrición. Está dedicada al estudio y divulgación de temas relacionados con la nutrición.

Introduction: in SARS-CoV-2-infected patients nutritional requirements are increased. These patients present symptoms that make food intake and nutrient absorption difficult, therefore involving nutritional risk. On the other hand, acute respiratory complications require prolonged ICU stays, and this predisposes to increased malnutrition and loss of skeletal muscle mass and function, which can lead to poor quality of life, disability and morbidity long after discharge. For this reason, the world's leading nutrition societies and associations believe that nutritional therapy should be considered a part of the basic treatment of patients with COVID-19. Methods: we have reviewed and compared 9 expert recommendations (ER) published by nutrition societies and associations from China, Spain, Brazil, Europe, Colombia, Australia, America, and the United Kingdom, in relation to critical and non-critical hospitalized patients due to the COVID-19 pandemic. Conclusions: the 9 ERs reviewed agree on the importance of nutritional management in critical and non-critical hospitalized patients with COVID-19, as well as on the early detection of nutritional risk, the intervention, and subsequent follow-up. Even so, each published document has its own particularities and puts a special stress on some specific aspect.