What foods should be avoided in a patient with impaired renal function undergoing regular hemodialysis (HD)?

Dietary Restrictions for Hemodialysis Patients

Patients on regular hemodialysis should primarily avoid high-sodium foods (limiting sodium to <2.3 g/day), foods with inorganic phosphorus additives, and should individualize potassium restriction based on serum levels rather than blanket avoidance of all high-potassium foods. 1

Sodium: The Primary Restriction

Sodium restriction is the most critical dietary modification for hemodialysis patients. 2, 1

• Limit sodium intake to less than 2.3 g per day (approximately 5-6 g of salt daily) to control blood pressure, reduce interdialytic weight gain, and minimize ultrafiltration requirements 1
• A 5 g sodium chloride diet should result in approximately 1.5 kg interdialytic weight gain in a 70 kg anuric patient on thrice-weekly hemodialysis 2
• More stringent restriction to 2.5-3.8 g salt daily (1-1.5 g sodium) may be necessary for hypertensive dialysis patients 2
• Foods to avoid: processed meats, canned soups, fast food, salty snacks, pickled foods, and restaurant meals 1

The evidence from Tassin, France demonstrated that combining dietary sodium limitation (85-100 mmol/day) with adequate dialysis reduced hypertension from 89% to only 5% requiring antihypertensive medications after 3 months 2

Phosphorus: Focus on Additives, Not Just Total Content

The key is avoiding inorganic phosphorus additives rather than restricting all phosphorus-containing foods. 1, 3

• Limit dietary phosphorus while maintaining adequate protein intake (typically 10-12 mg phosphorus per gram of protein) 1
• Foods to avoid: processed foods with phosphate additives (cola drinks, processed cheese, deli meats, packaged baked goods), as inorganic phosphorus is absorbed at 90-100% compared to 40-60% for organic phosphorus 3
• Use phosphate binders when dietary restriction alone is insufficient 1
• For patients >80 kg, estimate phosphorus needs by multiplying recommended protein intake by 10-12 mg 1

Potassium: Individualize Rather Than Blanket Restriction

Potassium restriction should be individualized based on serum levels, not uniformly applied to all hemodialysis patients. 1, 3, 4

• Adjust potassium intake to maintain serum levels within normal range 1
• The traditional approach of restricting all high-potassium foods lacks rigorous evidence from randomized controlled trials 4
• Critical nuance: Plant-based and animal-based potassium sources may differ in their contribution to hyperkalemia, though definitive data are lacking 4
• Foods high in omega-3 fatty acids (flaxseed, walnuts, soy) are also high in potassium; use their oils (walnut, flaxseed, canola) instead 1

Fluid Restriction

• Restrict fluids to 1.5-2 L/day for oliguric/anuric patients to prevent fluid overload 1
• Patients with residual kidney function may tolerate less restrictive limits 1

Foods to Emphasize (Not Avoid)

Hemodialysis patients need adequate protein and should not over-restrict their diet. 2, 1

• Consume 1.2-1.4 g protein/kg body weight/day (≥50% high biological value) 2
• Omega-3 fatty acids at least twice weekly from fish or supplemental sources (1-4 g EPA/DHA) 1
• Lean meats, poultry, fish, and legumes 1
• Fresh fruits and vegetables selected based on individual potassium tolerance 1
• Unsaturated fats from vegetables and oils 1

Cardiovascular Considerations

• Limit saturated fats to <10% of calories 1
• Restrict cholesterol to <300 mg/day 1
• Avoid trans-fatty acids 1
• Limit alcohol to 2 drinks/day for men, 1 drink/day for women 1

Critical Pitfalls to Avoid

Over-restriction is a major problem that can lead to malnutrition and worse outcomes. 5, 6

• Studies show 77% of hemodialysis patients consume less than recommended daily energy and 50% consume inadequate protein due to overly restrictive diets 5
• Traditional blanket restrictions on fruits, vegetables, nuts, legumes, dairy, and whole grains may deprive patients of heart-healthy diets and lead to more atherogenic eating patterns 3, 6
• Regular counseling by trained renal dietitians is essential to prevent malnutrition while managing electrolyte abnormalities 1, 7
• Nutritional assessments should occur at least every 6 months 1

The modern approach emphasizes a focus on whole foods low in sodium and phosphorus additives, rather than the traditional overly restrictive "renal diet" that may worsen quality of life and nutritional status. 3, 6