Nutritional Strategies to Prevent Muscle Loss and Sarcopenia in Chronic Kidney Disease: What Do We Currently Know?

Loss of muscle mass is an extremely frequent complication in patients with chronic kidney disease (CKD). The etiology of muscle loss in CKD is multifactorial and may depend on kidney disease itself, dialysis, the typical chronic low-grade inflammation present in patients with chronic kidney disease, but also metabolic acidosis, insulin resistance, vitamin D deficiency, hormonal imbalances, amino acid loss during dialysis, and reduced dietary intake. All these conditions together increase protein degradation, decrease protein synthesis, and lead to negative protein balance. Aging further exacerbates sarcopenia in CKD patients. Nutritional therapy, such as protein restriction, aims to manage uremic toxins and slow down the progression of CKD. Low-protein diets (LPDs) and very low-protein diets (VLPDs) supplemented with amino acids or ketoacids are commonly prescribed. Energy intake is crucial, with a higher intake associated with maintaining a neutral or positive nitrogen balance. Adequate nutritional and dietary support are fundamental in preventing nutritional inadequacies and, consequently, muscle wasting, which can occur in CKD patients. This review explores the causes of muscle loss in CKD and how it can be influenced by nutritional strategies aimed at improving muscle mass and muscle strength.

Can Mediterranean Diet Have a Positive Impact on Kidney Health? A Pending Answer to a Long-Time Question.

Dietary studies conducted in chronic kidney disease (CKD) patients were focused on the quantities of single nutrients, however it is possible that the excessive attention put on the restriction of proteins, sodium, potassium and phosphorus may compromise the overall quality of the diet in terms of micronutrients and palatability. Instead, concentrating on the nutritional quality healthy dietary patterns, may provide a better approach to improve nutritional prescriptions in CKD patients. All these dietary regimens share common features as reduced content of red meat, salt and saturated fatty acids, and higher fiber content, but may differ in terms of single nutrients consumption. In particular, Mediterranean Diet (Med Diet) has been associated with reduced incidence of diabetes, cardiovascular diseases and obesity, all conditions that are also strictly related to CKD. Given its low content of animal proteins and high contents of fiber it is possible that Med Diet may exert also positive effects on CKD as well as on its metabolic complications. In this review we summarize the role of Med Diet in primary prevention of CKD and on its progression.

Native Hypovitaminosis D in CKD Patients: From Experimental Evidence to Clinical Practice.

Native hypovitaminosis D (n-hVITD) is frequently found from the early stages of chronic kidney disease (CKD) and its prevalence increases with CKD progression. Even if the implications of n-hVITD in chronic kidney disease-mineral bone disorder (CKD-MBD) have been extensively characterized in the literature, there is a lot of debate nowadays about the so called "unconventional effects" of native vitamin D (25(OH)VitD) supplementation in CKD patients. In this review, highlights of the dimension of the problem of n-hVITD in CKD stages 2-5 ND patients will be presented. In addition, it will focus on the "unconventional effects" of 25(OH)VitD supplementation, the clinical impact of n-hVITD and the most significant interventional studies regarding 25(OH)VitD supplementation in CKD stages 2-5 ND.