Nutrition and chronic kidney disease

Denis Fouque et al Kidney International (2011) 80, 348–357

The incidence of malnutrition disorders in chronic kidney disease (CKD) appears unchanged over time, whereas patient-care and dialysis techniques continue to progress. Despite some evidence for cost-effective treatments, there are numerous caveats to applying these research findings on a daily care basis. There is a sustained generation of data confirming metabolic improvement when patients control their protein intake, even at early stages of CKD. A recent protein–energy wasting nomenclature allows a simpler approach to the diagnosis and causes of malnutrition. During maintenance dialysis, optimal protein and energy intakes have been recently challenged, and there is no longer an indication to control hyperphosphatemia through diet restriction. Recent measurements of energy expenditure in dialysis patients confirm very low physical activity, which affects energy requirements. Finally, inflammation, a common state during CKD, acts on both nutrient intake and catabolism, but is not a contraindication to a nutritional intervention, as patients do respond and improve their survival as well as do noninflamed patients.

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Fifty years after the first dialysis treatments, nutrition is still are current issue and many disorders are currently not well understood. However, there has been progress in nutritional targets in CKD patients before and during maintenance treatment. Before dialysis, there is good evidence that a longstanding nutritional care plan, with a control of protein intake, is efficient in correcting many metabolic disorders, including proteinuria, and is cost-effective. During dialysis, nutritional targets have gained in understanding and phosphate metabolism does not appear a sufficient issue to reduce protein intake, as compared with the risk of superimposed mortality when patients’ intakes are reduced. New devices recording physical activity report dramatically reduced energy expenditure in dialysis patients and call for sustained physical activity plans as a part of routine treatment. New classification of nutritional disorders in CKD patients may help physicians to more easily identify initial protein–energy wasting. Finally, inflammation, a common CKD disorder, is responsible for anorexia and catabolism, but inflamed patients can respond to supplemental nutrition as well as noninflamed ones.