Learning Objectives

By the end of this chapter, learners will be able to:
– Explain why nutrition is central to the management of chronic kidney disease (CKD) and dialysis.
– Select appropriate dietary modifications by CKD stage and renal replacement therapy (RRT) modality.
– Recognize and manage common nutritional complications in CKD, including protein–energy wasting (PEW), electrolyte disorders, and metabolic acidosis.
– Collaborate effectively with renal dietitians and apply practical counseling strategies.
– Understand the impact of nutrition on CKD–mineral and bone disorder (CKD-MBD) and cardiovascular (CV) risk.

28.1 Importance of Nutritional Management in CKD

Nutrition is a cornerstone of CKD care. Individualized dietary prescriptions can:
– Slow progression of CKD and reduce uremic toxin generation.
– Mitigate symptoms (e.g., fluid overload, pruritus), correct electrolyte and acid–base abnormalities.
– Prevent or treat PEW, CKD-MBD, and CV complications.
– Enhance quality of life and functional status.

Nutritional plans must be individualized by CKD stage, RRT modality, comorbidities (e.g., diabetes, heart failure), cultural preferences, and measured nutritional status.

28.2 Dietary Modifications in CKD

28.2.1 Energy Intake

• General targets: approximately 25–35 kcal/kg/day (actual or adjusted body weight), tailored to age, activity level, inflammation/illness, and weight goals.
• Adults <60 years: often 30–35 kcal/kg/day.
• Adults ≥60 years: often 25–30 kcal/kg/day.
• Peritoneal dialysis (PD) patients absorb glucose from dialysate; account for this absorbed energy when planning meals.

28.2.2 Protein Intake

• Non-dialysis CKD (stages 3–5): typically 0.55–0.80 g/kg/day. Use the higher end for older/frail patients to avoid PEW; monitor for adequacy. For people with diabetes, many clinicians target near 0.8 g/kg/day.
• Very-low-protein diets (0.28–0.43 g/kg/day) supplemented with ketoacid analogs can be considered in carefully selected, adherent patients with close specialist supervision.
• Dialysis:
• Hemodialysis (HD): ~1.0–1.2 g/kg/day (emphasize high biological value proteins).
• Peritoneal dialysis (PD): ~1.1–1.3 g/kg/day (to offset peritoneal protein losses).

28.2.3 Sodium Intake

• Typical target: ~1.5–2.3 g sodium/day (≈3.8–5.8 g salt), individualized by blood pressure, edema, and heart failure.
• Emphasize label reading, minimizing processed foods, and avoiding salt substitutes containing potassium chloride in patients at risk of hyperkalemia.

28.2.4 Potassium Intake

• Non-dialysis CKD: routine restriction is not required unless hyperkalemia is persistent or recurrent. Risk rises with lower eGFR, RAAS inhibitors, potassium-sparing diuretics, metabolic acidosis, and high dietary potassium.
• Dialysis: individualized restriction is common; counsel on high-potassium foods (e.g., bananas, oranges, tomatoes, potatoes, dark leafy greens) and preparation techniques (e.g., leaching/boiling vegetables). Optimize dialysis adequacy and address metabolic acidosis.

28.2.5 Phosphorus Intake

• Restriction is often needed in advanced CKD and in dialysis to prevent hyperphosphatemia and CKD-MBD.
• High sources: dairy, nuts/seeds, legumes, whole grains, processed meats and colas (phosphate additives).
• Bioavailability differs: additives > animal > plant (phytate) sources. Prioritize limiting additives and portion sizes.
• Phosphate binders (calcium-based and non-calcium-based) should be taken with meals; select and adjust per calcium status, PTH, and GI tolerance.

28.2.6 Calcium and Vitamin D

• Total calcium intake (diet + binders) should avoid excess to reduce vascular calcification risk, especially with hypercalcemia, low PTH, or adynamic bone disease.
• Active vitamin D analogs or calcimimetics may be indicated based on CKD-MBD profile and local protocols.

28.2.7 Fluid Intake

• Non-dialysis CKD: no blanket restriction; tailor to edema, hyponatremia, and heart failure.
• Dialysis: restrict based on residual urine and interdialytic weight gain (often aiming for <2–3 kg between HD sessions or individualized % of dry weight). Emphasize sodium restriction to reduce thirst.

28.2.8 Micronutrients and Supplements

• Water-soluble vitamins may be depleted in dialysis; consider renal-specific multivitamins as per local practice.
• Avoid routine high-dose vitamin A; limit vitamin C in dialysis (e.g., ≤100 mg/day) to reduce oxalate load unless otherwise indicated.
• Iron, folate, and B12 per anemia management protocols.

28.3 Management of Nutritional Complications

28.3.1 Protein–Energy Wasting (PEW)

• Features: unintentional weight loss, reduced muscle mass/strength, low dietary intake; labs (e.g., low albumin) support but are confounded by inflammation and fluid status.
• Screening/assessment: Subjective Global Assessment (SGA), Malnutrition–Inflammation Score (MIS), anthropometry, handgrip strength, dietary recalls.
• Management:
• Optimize energy (25–35 kcal/kg/day) and protein per modality; consider oral nutritional supplements.
• Address contributors: inflammation, acidosis, depression, dental issues, gastroparesis, inadequate dialysis.
• Intradialytic oral nutrition can be helpful in selected HD patients. Parenteral nutrition (including intradialytic parenteral nutrition) is reserved for selected refractory cases under specialist care.

28.3.2 Electrolyte and Acid–Base Disorders

• Hyperkalemia: dietary counseling, correct acidosis, review medications, consider potassium binders when indicated, and ensure dialysis adequacy.
• Hyperphosphatemia: dietary restriction, optimal binder regimen, vitamin D/calcimimetic therapy guided by CKD-MBD targets.
• Metabolic acidosis: consider oral bicarbonate when serum bicarbonate is persistently below target (commonly <22 mEq/L), with attention to volume status and sodium load; dietary alkali (fruits/vegetables) may help where potassium allows.

28.3.3 Dyslipidemia and CV Risk

• Emphasize overall cardioprotective patterns (e.g., reduced saturated/trans fats, high-fiber foods where potassium and phosphorus permit).
• Pharmacologic lipid-lowering per local CKD guidance and comorbidity profile.

28.4 Role of the Renal Dietitian

• Perform comprehensive assessments (dietary intake, weight trends adjusted for fluid, functional status, biochemical markers).
• Provide individualized meal plans and behavior-change counseling aligned with cultural preferences and health literacy.
• Educate on label reading, dining out strategies, hidden phosphate additives (“phos-”), and safe use of salt alternatives.
• Monitor and adjust plans to clinical changes (e.g., new RAAS inhibitor, switch to PD, intercurrent illness).

28.5 Impact of Nutrition on Bone Health and Cardiovascular Risk

• CKD-MBD: Manage phosphorus intake, ensure appropriate binder selection and timing, and titrate vitamin D/calcimimetic therapies per biochemical and clinical status. Prevent both hyper- and hypoparathyroidism; avoid calcium overload.
• CV risk: Sodium restriction, healthy fats, appropriate protein, and weight management aid blood pressure control, lipid optimization, and reduction of inflammation, contributing to lower CV morbidity and mortality.

28.6 Practical Dietary Planning and Monitoring

28.6.1 Suggested Targets (illustrative; individualize)

• Energy: 25–35 kcal/kg/day.
• Protein:
• CKD 3–5 (non-dialysis): 0.55–0.80 g/kg/day.
• HD: ~1.0–1.2 g/kg/day.
• PD: ~1.1–1.3 g/kg/day.
• Sodium: ~1.5–2.3 g/day.
• Potassium and phosphorus: individualized to labs, medications, and modality.

28.6.2 Monitoring Frequency (typical practice; adjust to setting)

• Weight and dietary intake: each visit (monthly in dialysis).
• Serum potassium, bicarbonate, phosphorus, calcium, albumin: regularly (e.g., monthly in dialysis; periodically in non-dialysis CKD).
• Handgrip strength or functional assessment: periodically.
• Interdialytic weight gain (HD) and glucose absorption impact (PD): ongoing.

SUMMARY

• Nutritional care is integral to slowing CKD progression, preventing complications, and improving quality of life.
• Energy targets of ~25–35 kcal/kg/day support weight and functional goals; protein needs vary by modality: lower in non-dialysis CKD, higher with dialysis.
• Sodium reduction improves BP and fluid control; potassium and phosphorus require individualized restriction, particularly in advanced CKD and during dialysis.
• Address PEW proactively with structured assessment, adequate energy/protein, treatment of contributors, and supplements when needed.
• Dietitians are essential partners for assessment, education, and ongoing adjustment.
• Nutrition is central to CKD-MBD control and CV risk reduction; avoid calcium overload and manage phosphate carefully.

CLINICAL PEARLS

• Always interpret albumin in the context of inflammation and hydration; do not use it alone as a nutrition marker.
• Plant-forward, low-protein meal plans can lower acid load and phosphorus bioavailability but require careful potassium monitoring.
• Phosphate additives in processed foods are highly absorbable; teaching patients to spot “phos-” on labels is impactful.
• For HD patients, counseling to limit inter-dialytic weight gain and sodium intake often reduces the need for aggressive ultrafiltration.
• Consider oral bicarbonate for persistent metabolic acidosis; correct acidosis may improve muscle protein balance and potassium control.
• PD patients often require higher protein and attention to total caloric intake due to dialysate glucose absorption.

VISUAL MATERIALS

Proposed diagrams/tables (to be created):
– Table: Suggested nutrient targets by CKD stage and modality (energy, protein, sodium, potassium, phosphorus).
– Flowchart: Stepwise management of hyperkalemia in CKD (diet, meds review, acidosis correction, binders, dialysis optimization).
– Infographic: Hidden dietary phosphorus sources and bioavailability.
– Diagram: Interplay between nutrition, CKD-MBD parameters, and vascular calcification risk.
– Patient handout layout: Label reading tips for sodium and phosphate additives.
– Schematic: Impact of PD dialysate glucose on daily energy balance.

MULTIPLE CHOICE QUESTIONS

1) For a motivated adult with CKD stage 4 (not on dialysis) and stable weight, which daily protein target is generally appropriate to reduce uremic toxin generation while minimizing PEW risk?
A) 0.3 g/kg/day without supplementation
B) 0.55–0.80 g/kg/day
C) 1.0–1.2 g/kg/day
D) ≥1.5 g/kg/day

Answer: B) 0.55–0.80 g/kg/day
Explanation: Moderate protein restriction is typical in non-dialysis CKD; lower targets risk PEW unless ketoacid-supplemented and closely supervised.

2) In hemodialysis, the most appropriate protein target to offset catabolic losses is:
A) 0.6–0.8 g/kg/day
B) 0.8–1.0 g/kg/day
C) 1.0–1.2 g/kg/day
D) ≥1.5 g/kg/day routinely

Answer: C) 1.0–1.2 g/kg/day
Explanation: Dialysis-related losses and catabolism warrant higher protein intake.

3) Which intervention most effectively reduces thirst and interdialytic weight gain in HD patients?
A) Avoiding fluids but continuing high-sodium foods
B) Sodium restriction with label reading and reduced processed foods
C) Eliminating all carbohydrates
D) High-protein supplements only on dialysis days

Answer: B) Sodium restriction with label reading and reduced processed foods
Explanation: Lower sodium intake reduces thirst and fluid retention.

4) A CKD stage 5 patient has persistent hyperphosphatemia. Which statement is most accurate?
A) Plant phosphorus is more absorbable than additives
B) Phosphate binders should be taken with meals
C) Calcium-based binders are preferred regardless of calcium/PTH
D) Diet has minimal effect on serum phosphorus

Answer: B) Phosphate binders should be taken with meals
Explanation: Binding dietary phosphorus requires co-administration with food; additive phosphorus is highly absorbable.

5) In CKD with recurrent hyperkalemia, the first step should include:
A) Universal elimination of all fruits and vegetables
B) Review of medications and correction of metabolic acidosis
C) Routine initiation of chronic potassium-binding resins without other changes
D) Switching to a high-protein ketogenic diet

Answer: B) Review of medications and correction of metabolic acidosis
Explanation: Identify reversible contributors before broad dietary exclusions or long-term binders.

6) For an older adult (>60 years) with CKD and low physical activity, a reasonable energy target is:
A) 15–20 kcal/kg/day
B) 25–30 kcal/kg/day
C) 35–40 kcal/kg/day
D) No specific target is needed

Answer: B) 25–30 kcal/kg/day
Explanation: Lower energy targets are typical in older or less active adults to maintain weight and function.

7) Which counseling point is correct regarding salt substitutes in CKD?
A) They are safe because they contain no sodium
B) Many contain potassium chloride and may worsen hyperkalemia
C) They are recommended for all dialysis patients
D) They lower phosphorus absorption

Answer: B) Many contain potassium chloride and may worsen hyperkalemia
Explanation: Potassium-containing substitutes can be hazardous in CKD.

8) Regarding micronutrients in dialysis patients:
A) High-dose vitamin A is recommended
B) Water-soluble vitamins can be depleted; renal-specific multivitamins may be used
C) Vitamin C has no limits in dialysis
D) Supplements are unnecessary if appetite is normal

Answer: B) Water-soluble vitamins can be depleted; renal-specific multivitamins may be used
Explanation: Dialysis can remove water-soluble vitamins; avoid excess vitamin A and high-dose vitamin C.

9) Which statement best reflects PEW assessment in CKD?
A) Serum albumin alone is a reliable marker of nutritional status
B) SGA or MIS, anthropometry, and dietary recall provide a more complete assessment
C) BMI increase excludes PEW
D) Only dialysis adequacy predicts PEW risk

Answer: B) SGA or MIS, anthropometry, and dietary recall provide a more complete assessment
Explanation: Multifactorial assessment is preferred; albumin is confounded by inflammation/volume.

10) In PD patients, which nutrition consideration is most specific to the modality?
A) Protein targets are consistently lower than in HD
B) Dialysate glucose absorption contributes to daily energy intake
C) Potassium intake is unrestricted
D) Phosphorus additives are not absorbed in PD

Answer: B) Dialysate glucose absorption contributes to daily energy intake
Explanation: Absorbed glucose requires accounting in caloric planning; PD often needs slightly higher protein.

POWERPOINT PRESENTATION

Slide 1: Title
– Nutrition in Kidney Disease – Why It Matters

Slide 2: Learning Objectives
– CKD nutrition goals, modality-specific needs, complications, team roles

Slide 3: Energy and Protein Targets
– Energy 25–35 kcal/kg/day; protein by CKD stage and modality

Slide 4: Sodium and Fluid Management
– Sodium 1.5–2.3 g/day; fluid goals; interdialytic weight gain targets

Slide 5: Potassium Management
– Risk factors for hyperkalemia; dietary strategies; preparation methods

Slide 6: Phosphorus and Calcium
– Food sources, bioavailability; binders with meals; avoid calcium overload

Slide 7: CKD-MBD and CV Risk
– Nutritional levers impacting bone turnover and vascular calcification

Slide 8: PEW Assessment and Treatment
– SGA/MIS, functional measures; optimize energy/protein; address contributors

Slide 9: Modality-Specific Nuances
– HD vs PD: protein needs, dialysate glucose, intradialytic nutrition

Slide 10: Micronutrients and Supplements
– Renal multivitamins, vitamin C limits, avoid vitamin A excess

Slide 11: Practical Counseling
– Label reading, hidden phosphates, salt substitutes, culture-tailored plans

Slide 12: Key Takeaways and Quiz
– Summary points; rapid MCQ review

Educational disclaimer: This chapter provides general educational information for clinicians and trainees. It is not a substitute for professional judgment, local protocols, or individualized patient care. Clinical decisions should be tailored to each patient’s context, laboratory data, and specialist recommendations.

Visual learning: Nutrition in Kidney Disease

Presentation resource: The Kidney Hub clinical-series PowerPoint for Chapters 22–30 accompanies these chapters for teaching use.