🍓Medical Nutrition Therapy II Unit 4 – Kidney Disease: Dietary Management

Kidney Function Basics

• Kidneys play a vital role in filtering waste products and excess fluids from the blood, producing urine
• Regulate blood pressure by controlling fluid balance and secreting hormones (renin, angiotensin)
• Maintain proper electrolyte balance, including sodium, potassium, and phosphorus levels
• Produce erythropoietin, a hormone that stimulates red blood cell production in the bone marrow
• Activate vitamin D, which is essential for calcium absorption and bone health
• Help maintain acid-base balance by excreting excess hydrogen ions and reabsorbing bicarbonate
• Kidneys receive about 20% of the cardiac output, allowing for efficient filtration and reabsorption

Types of Kidney Disease

• Acute kidney injury (AKI) sudden decline in kidney function, often reversible with proper treatment
• Chronic kidney disease (CKD) gradual, progressive loss of kidney function over months or years
• Glomerulonephritis inflammation of the glomeruli, the tiny filters in the kidneys (lupus nephritis, IgA nephropathy)
• Polycystic kidney disease (PKD) inherited disorder causing fluid-filled cysts to develop in the kidneys
• Diabetic nephropathy kidney damage caused by poorly controlled diabetes, leading to protein loss in urine
• Hypertensive nephropathy kidney damage resulting from chronic, uncontrolled high blood pressure
• Kidney stones solid deposits of minerals and salts that can cause obstruction and damage to the kidneys
• Renal artery stenosis narrowing of the arteries supplying blood to the kidneys, leading to decreased function

Nutritional Implications of Kidney Disease

• Protein metabolism is altered, leading to increased protein catabolism and muscle wasting
• Sodium and fluid retention can cause edema, hypertension, and congestive heart failure
• Hyperkalemia (high blood potassium) can occur due to decreased excretion, causing cardiac arrhythmias
• Hyperphosphatemia (high blood phosphorus) can lead to bone mineral disorders and vascular calcification
• Anemia develops due to decreased erythropoietin production and iron deficiency
• Vitamin D deficiency is common, leading to hypocalcemia and secondary hyperparathyroidism
• Metabolic acidosis can occur due to impaired acid excretion, leading to bone demineralization
• Malnutrition and weight loss are common due to poor appetite, dietary restrictions, and increased catabolism

Key Nutrients in Kidney Disease Management

• Protein intake should be adjusted based on stage of CKD and treatment modality (0.6-1.2 g/kg/day)
• Sodium restriction (1500-2000 mg/day) helps control blood pressure and fluid balance
• Potassium intake may need to be limited (2000-3000 mg/day) to prevent hyperkalemia
• Phosphorus restriction (800-1000 mg/day) is essential to prevent hyperphosphatemia and bone disorders
• Calcium intake should be monitored and adjusted based on serum levels and vitamin D status
• Iron supplementation may be necessary to treat anemia and support erythropoiesis
• Vitamin D supplementation (calcitriol, ergocalciferol) is often required to maintain bone health
• B-vitamin supplementation (folate, B6, B12) may be needed due to increased losses during dialysis

Dietary Strategies for Different Stages

• Stage 1-2 CKD: Focus on blood pressure control, glycemic control in diabetes, and healthy eating habits
• Stage 3 CKD: Introduce protein and phosphorus restrictions, monitor potassium and sodium intake
• Stage 4 CKD: Further restrict protein (0.6-0.8 g/kg/day), phosphorus, and potassium; limit fluid intake
• Stage 5 CKD (end-stage renal disease): Individualize diet based on dialysis modality and residual kidney function
• Hemodialysis: Higher protein needs (1.2 g/kg/day), strict fluid and sodium limits, potassium and phosphorus restrictions
• Peritoneal dialysis: Moderate protein intake (1.0-1.2 g/kg/day), higher carbohydrate and fat intake, monitor glucose absorption from dialysate
• Transplant recipients: Gradual liberalization of diet, monitor for side effects of immunosuppressive medications

Meal Planning and Food Choices

• Emphasize fruits and vegetables with low potassium content (apples, berries, carrots, green beans)
• Choose whole grains and starches with lower phosphorus content (rice, pasta, bread)
• Incorporate lean protein sources (poultry, fish, eggs) and limit high-phosphorus meats (organ meats, processed meats)
• Use herbs and spices instead of salt for flavoring; avoid high-sodium condiments and processed foods
• Monitor dairy intake based on phosphorus and calcium levels; choose lower-phosphorus options (ricotta, cream cheese)
• Limit high-potassium fruits and vegetables (bananas, oranges, potatoes, tomatoes) or leach them before cooking
• Encourage adequate fluid intake in early stages, but limit fluids in advanced CKD and dialysis
• Provide education on reading food labels and making appropriate choices when dining out

Monitoring and Adjusting Treatment

• Regularly assess nutritional status using anthropometric measures, biochemical markers, and dietary intake
• Monitor serum electrolytes (sodium, potassium, calcium, phosphorus) and adjust diet accordingly
• Assess fluid status and blood pressure; adjust sodium and fluid intake as needed
• Evaluate anemia and iron status; provide supplementation and adjust erythropoiesis-stimulating agents as necessary
• Monitor bone mineral markers (parathyroid hormone, vitamin D, alkaline phosphatase) and adjust treatment
• Assess for signs of malnutrition (weight loss, muscle wasting, hypoalbuminemia) and provide nutritional support
• Regularly review and adjust dietary prescriptions based on changes in kidney function, treatment modality, and overall health status
• Collaborate with the interdisciplinary team (nephrologists, nurses, pharmacists) to optimize patient care

Patient Education and Counseling

• Provide clear, easy-to-understand information about the role of diet in managing kidney disease
• Educate patients on the importance of adhering to dietary restrictions and the potential consequences of non-adherence
• Teach patients how to read food labels and make informed choices when grocery shopping or dining out
• Provide practical tips for meal planning, cooking, and managing dietary restrictions in social situations
• Encourage patients to maintain a food diary and review it with them to identify areas for improvement
• Address common barriers to adherence, such as food preferences, cultural practices, and financial constraints
• Involve family members and caregivers in education sessions to promote a supportive home environment
• Regularly assess patient understanding and provide ongoing education and support to maintain adherence
• Encourage patients to ask questions and express concerns; provide empathy and reassurance throughout the counseling process