What is the recommended diet for patients with nephrotic syndrome?

Dietary Management for Nephrotic Syndrome

Patients with nephrotic syndrome should receive expert dietary counseling focused on sodium restriction, adequate protein intake (0.8 g/kg/day for most adults), and high-calorie nutrition to prevent malnutrition while managing edema. 1, 2

Core Dietary Components

Sodium Restriction

• Restrict sodium intake to reduce edema and fluid retention, focusing on eliminating processed and restaurant foods rather than arbitrary numerical targets. 1
• The primary goal is assessment of volume status (overfill versus underfill) combined with salt restriction, as recommended for adult patients with kidney disease. 1
• In Canada, nearly 80% of sodium intake comes from processed and restaurant foods, so focus dietary counseling on reducing these sources rather than salt added during cooking. 1
• Avoid rigid sodium targets below 2 g/day in the absence of strong evidence, as overly restrictive diets risk malnutrition and poor adherence due to social, cultural, and financial difficulties. 1

Protein Intake

• Maintain protein intake at 0.8 g/kg body weight/day for metabolically stable adults with nephrotic syndrome to preserve nutritional status while managing proteinuria. 2, 3
• Avoid high protein intake (>1.3 g/kg/day) as this may worsen proteinuria and accelerate kidney disease progression. 2, 3
• For patients with preserved kidney function (GFR >30 mL/min) who have severe, refractory nephrotic syndrome, consider a very low-protein diet (0.3-0.4 g/kg/day) supplemented with essential amino acids under close dietitian supervision, as this paradoxically may induce remission. 2, 4
• Never restrict protein in children with nephrotic syndrome due to growth impairment risk. 3

Calorie and Fluid Management

• Ensure adequate energy intake of 25-35 kcal/kg body weight/day to prevent protein-energy wasting, which increases morbidity and mortality. 2, 3
• Fluid restriction is indicated for hyponatremia and severe edema cases. 1
• Use concentrated, high-calorie formulas to meet age-related energy needs while limiting fluid volume, particularly in pediatric patients. 1

Potassium and Phosphorus

• Individualize potassium restriction (typically 2-4 g/day) based on serum levels and CKD stage, as nephrotic syndrome patients may have variable potassium handling. 1, 3
• Restrict phosphorus to 0.8-1.0 g/day if CKD stages 3-4 are present. 3

Dietary Pattern Recommendations

• Emphasize plant-based foods over animal-based foods and minimize ultraprocessed foods. 3
• Encourage fresh fruits and vegetables, which provide additional benefits for kidney outcomes while naturally being lower in sodium. 1
• Use low-fat or nonfat dairy products and reduce meat consumption. 3

Implementation Strategy

Expert Consultation

• All patients with nephrotic syndrome require assessment and ongoing advice from a renal dietitian, including individualized guidance on salt, potassium, calorie, and protein intake. 1, 2, 3
• Tailor dietary education to disease severity, presence of CKD, and individual metabolic stability. 1, 2

Monitoring Requirements

• Monitor nutritional status regularly through appetite assessment, dietary intake evaluation, body weight changes, biochemical markers (albumin, prealbumin), and anthropometric measurements. 2, 3
• Watch for signs of protein-energy wasting, including declining serum albumin, weight loss, and muscle wasting. 2, 3
• Track electrolytes (particularly potassium and phosphorus), which may be affected by dietary changes. 2

Common Pitfalls to Avoid

• Never implement protein restriction without proper nutritional counseling, as this significantly increases malnutrition risk. 2, 3
• Do not focus solely on protein restriction while ignoring overall diet quality (sodium, phosphorus, potassium), as this approach is counterproductive. 2
• Avoid overly restrictive diets in frail, elderly, or malnourished patients, as the priority shifts to encouraging adequate food intake and preventing further nutritional decline. 1
• Do not prescribe low or very low-protein diets in metabolically unstable patients with CKD. 2
• Recognize that hypovolemic patients are particularly prone to complications from aggressive dietary sodium restriction combined with diuretics. 5

Special Considerations

Congenital Nephrotic Syndrome

• Fluid prescription should primarily provide adequate nutrition using concentrated formulas. 1
• Consider regular albumin infusions (1-4 g/kg/day) based on clinical indicators of hypovolemia (prolonged capillary refill, tachycardia, hypotension, oliguria) rather than serum albumin levels alone. 1

Patients with Advanced CKD

• For older adults with frailty or sarcopenia, consider higher protein and calorie targets to prevent muscle wasting. 2
• For dialysis patients, increase protein intake to 1.0-1.2 g/kg/day to maintain nutritional status. 2