Chronic kidney disease (CKD) is a progressive disease in which kidney function is lost over a period of years. It has a number of consequences including cardiovascular diseases, osteodystrophy, pericarditis and anaemia. It is most commonly caused by diabetes or untreated high blood pressure, but can also arise due to inflammatory disorders. The progression of CKD is classified as stages 1-5, with stage 1 representing the very early phase with mild impairment of glomerular filtration rate, and stage 5 representing full renal failure.

The impairment of metabolic functions associated with CKD requires dietary modification in order to prevent more rapid progression of disease and the development of serious complications. In the early stages of disease, dietary modification such as reduction of sodium intake, may be the only treatment offered to people with CKD, but as disease progresses, such modifications become more important if the affected individuals require kidney function to be supported by haemodialysis. Dietary changes in CKD are generally not required for those who have stages 1-3 CKD. However, once stage 4 CKD is reached, the changes to diet can be lifelong, maintained outside clinical settings and must be self-managed by the patient. Dietary modifications in those with advanced CKD will extend to management of potassium and phosphorus intake and control over fluid balance for people requiring dialysis.

In the initial stages of pre-dialysis care there will be a number of factors which appear overwhelming for the individual and make compliance with dietary change problematic. The psychological and behavioural challenges that accompany dietary change will persist for extended periods, particularly as the diet might need to vary as the disease progresses. Integrating the renal diet into normal life is particularly challenging in situations outside the home, such as at work or in social situations, but also necessitates changes within the family around meal preparation and the eating environment, especially if the person affected is a child.

The nutritional management of people who have kidney disease is important to consider, especially in terms of slowing the rate of renal deterioration and controlling the development and progression of co-morbidities. The challenge is to find the balance between maintaining independence and a high quality of life in the early stages of disease and ensuring adequate monitoring and intervention to limit disease progression.  Malnutrition is common in people who undergo dialysis treatments and this increases the risk of co-morbidities and mortality. Patients are also at risk of other nutritional problems including disturbed calcium and phosphate status, which stems from insufficiency of serum 25-hydroxy vitamin D. Anaemia is also an issue for patients with CKD and is one of the factors which impinges significantly on quality of life and cardiovascular complications. Monitoring nutritional status and specific indicators of malnutrition and micronutrient balance has to be a key element of managing individuals with CKD.

As many of the dietary changes required have to be self-managed by people with CKD, information provided by dietitians is clearly critical in helping to adjust to and maintain new dietary patterns. Increasingly the self-managing patient will utilize information available online. This is often of low quality, hard to understand and frequently inaccurate. Dietitians therefore play a key role in educating patients on how to adhere to their therapeutic diet and, in addition to improving adherence with specific protocols and can help patients adapt to the challenges of lifestyle change.

Further reading

Morris A, Love H, van Aar Z, Liles C, Roskell C (2017). Integrating renal nutrition guidelines into daily family life: a qualitative exploration. J Human Nutr Dietetics DOI: 10.1111/jhn.12483

Lambert K, Mullan J, Mansfield A, Koukomous A, Mesiti L (2017). Evaluation of the quality and health literacy demand of online renal diet information. J Human Nutr Dietetics DOI: 10.1111/jhn.12466

Rizk R, Karavetian M, Hiligsmann M, Evers SMAA (2017). Effect of stage-based education provided by dedicated dietitians on hyperphospataemic haemodialysis patients: results from the Nutrition Education for Management of Osteodystrophy randomised controlled trial. J Human Nutr Dietetics DOI: 10.1111/jhn.12472

Sridharan S, Wong J, Vilar E, et al., Comparison of energy estimates in chronic kidney disease using doubly-labelled water. J Human Nutr Dietetics 29, 59-66.

Ruperto M, Sanchez-Muniz FJ, Barril G (2016). Predictors of protein-energy wasting in haemodialysis patients: a cross-sectional study. J Human Nutr Dietetics 29, 38-47.

El-Katab S, Omichi Y, Srivareerat M, et al. (2016). Pinch grip strength as an alternative assessment to hand grip strength for assessing muscle strength in patients with chronic kidney disease treated by haemodialysis: a prospective audit. J Human Nutr Dietetics 29, 48-51.

Hanna K, Fassett RG, Gill E, et al., (2015). Serum 25-hydroxy vitamin D concentrations are more deficient/insufficient in peritoneal than haemodialysis patients in a sunny climate. J Human Nutr Dietetics 28, 209-218.