Dietary Therapy in Dialysis Patients

The risk of cardiovascular disease (CVD) and mortality in patients with end-stage kidney disease (ESKD) is far greater than those in the general population. Emerging evidence suggests that unhealthy diet causes altered mineral metabolism, disturbance of gut microbiota (dysbiosis) with elevated uremic toxin level, immune dysregulation, and inflammation; these abnormalities are strongly related to development of CVD. Little is known about the relationship between therapeutic diet intervention and cardiovascular risk in patients with ESKD. Recently, the study of the investigators showed that ESKD patients undergoing hemodialysis who consumed very low-phosphate diet, phosphate-to-protein ratio (PPR) value of 8 mg/g, experienced an extra reduction of serum phosphorus level by 0.61 mg/dL compared with that of low-phosphate diet, PPR value of 10 mg/g.

The aim of the study is to explore the effect of 7-day therapeutic diet intervention on changes of altered mineral metabolism, uremic toxin production, immune dysregulation and inflammation, highlighting the important role of dietary modification in dialysis population.

It is to conduct a randomized controlled trial with cross-over design at a hemodialysis unit of tertiary teaching hospital in Northern Taiwan. Subjects with aged older than 20 years, ESKD undergoing maintenance dialysis for more than three months, having adequate dialysis and serum intact parathyroid hormone less than 800 pg/mL will be included. Participants will be randomly assigned into two groups: those in group A will receive study diet for 7 days, followed by 4-week washout period and then receive 7-day usual diet. The opposite order of diets will be prescribed in group B. The study meals are prepared in the hospital cafeteria. Dietary compositions of the study diets were analyzed before the start of the study. The study outcome measures are difference in change-from-baseline values of altered mineral metabolism, uremic toxin production, immune dysregulation and inflammation between the therapeutic diet and the usual diet.

Inclusion criteria

• Subjects with aged older than 20 years, ESKD undergoing maintenance dialysis for more than three months, having adequate dialysis, serum intact parathyroid hormone less than 800 pg/mL and good dietary compliance

Exclusion criteria

• Patients who meet any of the following criteria will be excluded from the study:

• Serum albumin level less than 2.5 g/dL
• Hospitalization within the past 4 weeks
• Prebiotics, probiotics, symbiotics or antibiotics use within the past 4 weeks
• History of psychiatric disorders
• Having mental retardation
• Those who dislike of the study meals
• Soft diet requirement
• Vegetarian