Peritoneal Dialysis
This type of dialysis involves the removal of waste products and water within the peritoneal cavity, using the peritoneal membrane as a filter.  In peritoneal dialysis, the dialysis solution (dialysate) is instilled through the peritoneal catheter into the peritoneal cavity or peritoneum.  The many blood vessels and capillaries throughout the peritoneum are separated from the peritoneal cavity by a layer of mesothelium.  Passive movement from the peritoneal capillaries into the dialysate removes the uremic toxins.  The high osmolality of the dialysate due to the high dextrose concentration results in the removal of extracellular fluid.  There are two major types of peritoneal dialysis (intermittent peritoneal dialysis also is available; however, it is not used as a standard treatment):

• Continuous ambulatory peritoneal dialysis (CAPD), whereby a continuous presence of a dialysate in the peritoneal cavity is interrupted intermittently for drainage and instillation of fresh dialysate.  The exchanges are usually done four times a day, with only a 30- to 35-minute interruption of daily activity for each exchange.  The dialysate is allowed to dwell in the peritoneal cavity for 3½ to 4 hours during the day and about 8 to 10 hours at night.
• Continuous cyclic peritoneal dialysis (CCPD), which allows for more daytime freedom by decreasing the catheter connections to two a day.  A cycler machine is used to deliver three or four exchanges each night, lasting 2½ to 3 hours each.  Approximately 2 L of dialysate is left in the peritoneal cavity during the day.  The residual fluid remains in the abdomen for 12 to 15 hours and is drained when the patient begins the nightly routine again.

    Peritoneal dialysis can increase the risk for hypokalemia, since most commercially available solutions do not contain potassium (2).  Potassium can be easily added to the dialysate if needed.  Peritoneal dialysis can provide a substantial amount of energy from glucose to the patient via the dialysate.  The amount of total kilocalories absorbed depends on the volume infused, its dwell time, and the concentration of dextrose used (2).  See Determination of Glucose Absorption During Peritoneal Dialysis.Common complaints of patients using peritoneal dialysis include bloating, abdominal fullness, and loss of appetite from the indwelling dialysate, which can affect nutritional intake (2).

Alternative Dialytic Treatments: Continuous RRT
Continuous arteriovenous hemofiltration (CAVH) and continuous venovenous hemofiltration (CVVH) use a polysulfane membrane to remove some of the solutes.  No dialysis is used because adequate clearance of nitrogenous waste and other byproducts of metabolism and fluids can be achieved.  This procedure is often used in the critical care setting where patients are hemodynamically unstable.  When CAVH is used, protein requirements should be estimated in a range of 1.5 to 1.8 g/kg per day because the losses of small peptides and amino acids can be high (2-4).  Use of continuous RRT often makes it possible to provide nutrition support without the need to restrict protein and fluid (2). 

Transplantation
A transplant offers a relatively favorable long-term outlook and adds several productive years for some individuals with end-stage renal disease (ESRD), especially young children.  A functioning transplanted kidney performs the excretory and regulatory functions of a normal kidney.  Successful transplantation frees the patient from the time-consuming demands of dialysis and a strict dietary regimen.  Refer to Guidelines for Nutrition Care of Renal Patients (1) for specific nutrition guidelines before and after transplantation for adults.

Nutritional Adequacy
Because individual diets in renal disease may vary widely as to the nutrients controlled, a general statement on nutritional adequacy is not given.  Refer to statements for each constituent in the respective sections:

• Nutrition Management of Potassium Intake
• Sodium-Controlled Diets
• Nutrition Management of Phosphorus Intake
• Protein-Controlled Diet

How to Order the Diet
Refer to the “How to Order the Diet” instructions for each of the components required in the respective chapters. See Nutritional Adequacy on the preceding page.  Also refer to Nutrition Management of Fluid Intake.

Planning the Diet
Refer to Table G-2: Nutritional Requirements for Adults with Renal Disease Based on Type of Therapy

Energy
Energy requirements in CKD without dialysis are similar to that of healthy individuals and are influenced by age, sex, and physical activity (5).  According to studies, resting metabolic rates were similar for patients with CKD and controls by direct and indirect calorimetry.  Nitrogen balance studies using < .8 g protein/kg/IBW (RDA) reported a neutral or positive nitrogen balance when energy intakes were 35 to 45 kcal/kg/IBW (5) and a negative nitrogen balance when energy intakes were 15 to 25 kcal/kg/IBW.  Therefore energy intakes should be greater in patients following diets containing less than the RDA for protein (Grade I) (5). The energy intake for persons with CKD should be adequate to maintain or achieve reasonable body weight and positive nitrogen balance.  In patients with pre-ESRD and those receiving dialysis, an energy intake of 35 kcal/kg of ideal body weight (IBW) (1,6) has been suggested.    Thirty to 35 kcal/kg IBW is recommended for individuals 60 years or older (1,6,7).   More recently, The American Dietetic Association explored evidence that reported the accuracy and application of various methods used to measure energy expenditure.  For additional information, refer to Estimating Energy Expenditure. 

    In peritoneal dialysis, glucose is absorbed from the dialysate.  Dietary energy may need to be decreased to prevent excess weight gain and obesity.  An average weight gain of 5 kg/year has been reported.  Glucose absorption varies in each patient due to individual peritoneal permeability.  Some patients undergoing CAPD or CCPD have been shown to absorb more than 800 kcal/day from the dialysate, depending on which exchange concentrations are used.  See Determination of Glucose Absorption in Peritoneal Dialysis.  It is suggested that kilocalories absorbed from dialysate be subtracted from daily energy intake (1,6).

Protein
Pre-ESRD: It is thought that a low protein intake reduces intraglomerular pressure, solute load, and overall nephron activity and may preserve renal function or delay the progression of decline in renal function (2).  Evidence from the Modification of Diet in Renal Disease (MDRD) trial indicates that protein restriction can slow progression of CKD (8).  The most recent guidelines recommend that the protein be based on the patient’s creatinine clearance, glomerular filtration rate (GFR), and urinary protein losses (1).  The general recommendation is 0.6 to 1.0 g/kg of IBW , with 50% of protein source coming from high biological value (HBV) animal and/or plant sources (1,6).  More specific recommendations for dietary protein in progressive renal failure have been suggested (3,7,9). They include 0.8 g/kg per day, 50% HBV, along with sufficient energy in the patient with no symptoms of uremia and when the GFR is greater than or equal to 55 mL/min.  When the GFR is 25 to 55 mL/min, the use of 0.6 g/kg per day of protein, 50% HBV, has been found to be beneficial in terms of reducing or eliminating uremic symptoms and slowing the loss of renal function (3,7,9).

    Hemodialysis:  The protein recommendation for patients undergoing hemodialysis three times a week is 1.1 to 1.4 g/kg of IBW per day (1,6).  Some researchers recommend an additional 0.2 g/kg per day as protein or essential amino acids (4,6,10).  In a single hemodialysis treatment in a nonfasting patient, 10 to 13 g of amino acids and small peptides are lost (2).  About 30% to 40% of the amino acids lost during hemodialysis are essential.  Therefore, HBV protein should represent at least 50% of the total protein content of the diet (1,6).  Reuse of dialyzers may increase amino acid losses, depending on the composition of the dialyzer.

    Peritoneal dialysis: In peritoneal dialysis, the patient’s requirement for protein is increased to 1.2 to 1.5 g/kg IBW (1,6).  Protein requirements may even be higher depending on stress or metabolic needs.  When used for long-term management of CKD, peritoneal dialysis has been associated with progressive wasting and malnutrition (2).  Several factors contribute to this wasting, including anorexia (caused by inadequate dialysis, superimposed additional and secondary illnesses, discomfort, fullness, or severe dietary restriction); losses to dialysate of protein, amino acids, and vitamins; and peritonitis leading to catabolism.  (During episodes of peritonitis, there are increased protein losses, which continue several days to 1 week after the clinical signs of peritonitis subside.  Some researchers believe this loss may continue for even longer periods.)  Protein and albumin losses with the dialysate vary from patient to patient but are fairly consistent within an individual.  Of the protein lost, 66% to 80% is albumin.  Protein losses in patients undergoing CCPD approximate those in patients receiving CAPD.  A minimum protein intake of 1.2 to 1.3 g/kg of IBW per day has been suggested for clinically stable patients undergoing CAPD (7).

Fat
Elevated lipoproteins and abnormalities in lipid metabolism are common in patients with CKD (1). The National Kidney Foundation Task Force on Cardiovascular Disease has recommended the use of the National Cholesterol Education Program (NCEP)Adult Treatment Panel III guidelines for patients with chronic renal disease (1).  For patients with renal disease, the target goals for cholesterol are modified slightly because of data from morbidity and mortality studies (1).  For therapeutic lifestyle diet modifications, see Medical Nutrition Therapy for Disorders of Lipid Metabolism.

Table G-1: Recommended Lipid Levels in Renal Failure

Stage of Renal Failure	Recommended Levels*
Pre-ESRD	Cholesterol 120-240 mg/dL Triglycerides (fasting) <200 mg/dL
Dialysis	Cholesterol 150-250 mg/dL

*Levels listed may be measured as nonfasting levels except where indicated.
Source: Wiggins KL, ed.  Guidelines for Nutrition Care of Renal Patients.  Chicago, Ill: American Dietetic Association; 2002.

Sodium and Fluid
Pre-ESRD:  The sodium recommendation for patients with pre-ESRD should be individualized; a range of 1 to 3 g/day is suggested (1,6).  Fluid requirements should be sufficient to maintain appropriate hydration status (1,6).

    Hemodialysis: The allowance for the hemodialysis patient can vary from 2 to 3 g of sodium per day and depends largely on urine output (1,6).  The more urine the patient produces, the more sodium the patient may eliminate via the urine.  Under steady-state conditions, urinary output usually provides a good guide for the fluid intake.  Urine output per day plus 500 to 750 mL of fluid is recommended to maintain fluid weight gain between hemodialysis treatments of less than 5% interdialytic weight (1,6).  If the patient is anuric, 1,000 mL per day is recommended (6).

    Peritoneal dialysis: Sodium balance and blood pressure can be well controlled with CAPD or CCPD.  As much as 5,700 mg/day of sodium can be removed with CAPD.  The patient must be aware of the symptoms of hypotension and the methods for avoiding it.  For sodium requirements, each patient must be individually evaluated for parameters such as weight (dry weight vs fluid weight), blood pressure (hypotension or hypertension), shortness of breath, and edema.  Most patients’ sodium should be in the range of 2 to 4 g/day (1,6). Fluid generally is not restricted for patients receiving CAPD or CCPD, but patients should know how to monitor their weight and blood pressure.  Adjustments in fluid balance can be made by altering the quantity or strength of hypertonic solutions.  Patients must take their own blood pressure readings and weigh themselves regularly to determine the concentration of exchanges necessary to maintain fluid balance (1,6).

Potassium
Pre-ESRD: The potassium requirements should be individualized based on laboratory values in patients with pre-ESRD (1,6). 

    Hemodialysis: For patients receiving hemodialysis, 40 mg/kg of IBW is recommended, or based on laboratory values (1,6). Hemodialysis does remove potassium; therefore, monitoring levels and ensuring adequate intake is important (2). 

    Peritoneal dialysis: Patients receiving CAPD or CCPD may not need potassium restrictions; however, a final assessment should be based on interpretation of the laboratory values (1,6). Peritoneal dialysis can increase the risk for hypokalemia, since most commercially available solutions do not contain potassium (2).  Potassium can be easily added to the dialysate if needed.

Phosphorus
Pre-ESRD: Phosphorus should be individualized, or 8 to 12 mg/kg of IBW.  A phosphate binder may be required (1,6). Hemodialysis and peritoneal dialysis:  Phosphorus is individualized, or <17 mg/kg of IBW (1,6).  Hyperphosphatemia usually develops when the GFR falls below 25 mL/minute. Phosphate binders may be initiated as early as when the GFR is 60. Hyperphosphatemia is harmful because it contributes to secondary hyperparathyroidism.  Control of serum phosphorus is usually not possible by diet alone.  Phosphate binders are given at mealtimes to bind the phosphate from food.  The prescribed amount should be individualized according to the amount of phosphate present in a meal.  The general dietary recommendation is less than or equal to 17 mg/kg of IBW (1,6).  Approximately 60% to 70% of phosphorus (PO4)  ingested is absorbed (11-13) .  One gram of calcium carbonate (CaCO3) binds roughly 40 to 60 mg of PO4, and 1 g of calcium acetate binds 39 mg of PO4. Whereas CaCO3 contains 40% elemental calcium, calcium acetate is composed of 25% elemental calcium.  As a standard, calcium acetate contains 167 mg of elemental calcium in each tablet, and CaCO3 contains 500 mg.  With an elevated calcium/PO4 product, sevelamer hydrochloride may be more effective and will not contribute to elevated phosphorus and calcium levels.  One, two, or three tablets of calcium acetate would be replaced with one, two, or three tablets of sevelamer hydrochloride (14,15).  If calcium and phosphorus levels are at the high end of normal range, use of a calcium binder may make the calcium/phosphorus product exceed the normal range and contribute to soft-tissue calcification.  The goal is for the serum calcium-phosphorus product to be under 55 mg2/dL2 (11).  Aluminum-containing phosphate binders are generally not recommended due to risk for aluminum toxicity, which can lead to osteodystrophy, anemia, and encephalopathy (2).

Calcium
Pre-ESRD:  Calcium intake should be individualized based on calcium, phosphorus, and parathyroid hormone (PTH) laboratory values; use of vitamin D; and use of supplements that impact the calcium level should also be considered (1,6).

     Hemodialysis and peritoneal dialysis: Calcium intake should be approximately 1,000 to 1,500 mg/day or individualized based on calcium, phosphorus, PTH laboratory values, and use of vitamin D supplementation (1,6). Calcium supplementation frequently is prescribed.  Intestinal absorption of calcium is impaired in uremia due to the lack of the active form of vitamin D (2).  Also, diets prescribed for patients with pre-ESRD tend to be low in calcium because of the restriction of dairy products.  Calcium supplements containing 1 to 2 g/day of elemental calcium may be given.  As in Pre-ESRD, the general dietary recommendation depends on the serum level and other factors (see above discussion.  Calcium supplements are taken between meals and are not to be confused with those used to bind phosphorus.  An activated form of vitamin D (calcitriol) also can be used to enhance calcium absorption.

Magnesium
The kidney is the organ primarily responsible for the normal maintenance of serum magnesium.  Most patients with uremia should avoid the use of laxatives, enemas, antacids, or phosphate binders containing magnesium.  Hypermagnesemia may occur when the tap water used to prepare the dialysate contains excess magnesium. The usual hemodialysis solution magnesium level is 0.5 to 1 mEq/L (16). Excess magnesium accumulates largely in bone, where it is deleterious to bone metabolism.  Symptoms include muscle weakness, hypotension, electrocardiographic changes, sedation, and confusion.  Magnesium may be decreased in dialysate and used as a phosphate binder along with CaCO3.

Guidelines for Vitamin and Trace Mineral Supplementation in CKD
Vitamins:  Studies do not support routine supplementation of fat-soluble vitamins other than vitamin D for patients consuming well-balanced, adequate diets.  Patients can be supplemented with 1,25 dihydroxyvitamin D, the most active metabolite of vitamin D metabolism, to maintain normal calcium homeostasis and prevent osteomalacia (2).  Patients can receive supplementation with vitamin D analogs for the treatment of secondary hyperparathyroidism..  Paricalcitol (Zemplar) and doxercalciferol (Hectorol) are presently available.  The advantage of using the analogs as opposed to calcitriol is decreased absorption of phosphorus and calcium in the gut (17).  Supplementation with 1,25-dihydroxycholecalciferol, the active form of vitamin D in the presence of CaCO3, must be individualized and its effects on calcium levels must be frequently monitored (10).  Vitamin K may be considered for the patient who has been receiving antibiotic therapy.  Vitamin A should not be supplemented if RRT is not used, since excessive amounts can lead to toxicity (2).  Water-soluble vitamins, especially vitamin C, folate, and pyridoxine should be evaluated, as deficiencies may occur secondary to poor appetite, altered metabolism, uremia, removal by dialysis, and restricted diet (2).  According to recent guidelines, each patient should be evaluated and treated with vitamins according to individual need and after appropriate assessment of biochemical levels (1,6).  It has been recommended to provide 70 to 100 mg/d of vitamin C in adults receiving RRT; however, doses greater than 200 mg/d have shown to elevate blood oxalate levels, which can result in deposition of oxalate in the heart, kidney and blood vessels (2).  Recommendations for folate and pyridoxine remain controversial (2).  Pyridoxine supplementation of 5 mg/d or 50 mg three times a week has been advised in patients on CAPD (2). Folic acid recommendations of 1 mg/day have been suggested for all patients receiving RRT (2).

Trace minerals: Patients with CKD experience alterations in trace mineral metabolism. Serum or tissue levels or both can be high or low.  Trace minerals should be supplemented or restricted only after appropriate biochemical assessments have been made (1,6). 

Food List	Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
Dairy and phosphorus	2-8	100-400	30-300	50-400	100-120

Table G4.4:  Bread, Cereal, and Grain Choices
Bread, Cereal, and Grain Choices:  This group of foods generally provides 2 to 3 g protein per serving. Grain foods with higher values of sodium, potassium, and/or phosphorus are identified.  These foods can be integrated in the meal plan to meet nutrition needs.  Laboratory values, use of phosphate binders, and type/frequency of dialysis therapy should be considered to determine servings recommended per day.

Food List	Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
Breads, rolls, cereals, grains, crackers, snacks, desserts	2-3	50-200	0-150	10-100	10-70
Higher sodium and/or phosphorus grain foods	2-3	50-200	150-400 (if marked with b**)	10-100 (if marked with c***)	100-200 (if marked with a*)

a*—food contains 100-200 mg phosphorus per serving.
**b—food contains 150-400 mg sodium per serving.
***c—food contains 10-100 mg potassium per serving.

Table G4.5:  Calorie and Flavoring Choices
Calorie and Flavoring Choices:  Foods grouped in this category help to add extra calories and flavor to foods to help enhance caloric intake and can be used to help prevent weight loss.

Food List	Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
Calorie choices	0-1	100-150	0-100	0-100	0-100
Flavor choices	0	0-20	250-300	0-100	0-20

Table G4:6:  Vegetarian Protein Choices
Vegetarian Choices:  The section on vegetarian choices is intended for patients who avoid animal foods.  It can replace the protein choices section (Table G4.1).  Table G4.6 provides nutrient values of vegetarian proteins and foods categorized in this group.  Choosing vegetarian proteins over animal proteins may result in higher intakes of potassium and phosphorus per gram of protein.  Higher sodium, potassium, and phosphorus foods are identified and often can be used once or twice per week depending on lab values, fluid weight gains, and dialysis therapy.

Food List	Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
Protein foods	6-8	70-150	10-200	60-150	80-150
Higher sodium, potassium, or phosphorus proteins	6-8	70-150	250-400	250-500 (marked with b)	200-400 (marked with a)

Calculating Food Choices for People on Dialysis (1,3)

1. Refer to Table G-2: Nutritional Requirements for Adults With Renal Disease Based on Type of Therapy to determine nutrition needs.  Priorities in meal planning for people on dialysis will vary with their nutrition status, laboratory values and type/frequency of dialysis therapy.
2. Once nutrition needs are known, calculate and identify protein needs and determine choices.  At least 50% of the protein should come from the Protein Choices Food List (Table G4.1) to ensure high-biological proteins are consumed. Choices from the higher sodium, potassium, and phosphorus groups can be included as needed by the dietitian’s discretion to meet the patient’s nutrition needs.
3. Other protein foods can then be selected to fulfill protein and nutrient requirements (refer to Tables G4.2 to G4.4.).  The amount of sodium, potassium, and phosphorus should be determined based on the patient’s laboratory values, medications (eg, phosphorus binders) and type/frequency of dialysis.
4. Calorie and flavoring choices can be used to provide balance, flavor, and additional calories to meet nutrition needs and complete the patient’s meal plan (refer to Table G4.5).

PROTEIN CHOICES FOOD LIST
Animal Protein: Serving 1 oz

Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
6-8	50-100	20-150	50-150	50-100
Beef (1 oz) Egg substitutes (¼ cup) Eggs (1 large) Fish (1 oz) Lamb (1 oz) Pork (1 oz) Poultry (1 oz) Shellfish (1 oz) Veal (1 oz) Wild game (1 oz)

High Sodium, Potassium, Phosphorus, Protein Food Lists

Protein (g/serving)	Calories (kcal/serving)	Sodium (mg/serving)	Potassium (mg/serving)	Phosphorus (mg/serving)
6-8	50-100	200-500 (if marked b**)	250-450 (if marked c***)	100-300 (if marked a*)
Bacon, breakfast sausage b (4 slices, 1 ½ patties, or 3 links) Canned tuna, canned salmon, or sardines a,b (¼ cup) Cheeses, all kinds a,b (1 oz) Cooked, dried beans and peas a,c (½ cup) Cottage cheese b (¼ cup) Deli-style roast beef, ham, turkey (1 oz) b Frankfurters, bratwurst, polish sausage (2 oz) b Luncheon meats, bologna, liverwurst, salami, etc (2 oz) b Milk (1 cup) a,b Nut butters (2 tbsp) a Nuts (¼ cup) a,c Organ meats (1 oz) a Soy milk (1 cup) c Tofu (¼ cup) a Vegetarian meat analogs (garden burgers, soy burgers, etc) (2 oz) b Yogurt (1 cup) a,b,c

*a- food contains 100-300 mg phosphorus/serving           **b- food contains 200-500 mg sodium/serving
***c- food contains 250-450 mg potassium/serving

References

1. National Renal Diet Professional Guide.  2nd ed.  Chicago, Ill: Renal Practice Group of the American Dietetic Association; 2002.
2. Schiro Harvey K.  A Healthy Food Guide for People With Chronic Kidney Disease.  2nd ed.  Chicago, Ill: Renal Practice Group of the American Dietetic Association; 2002
3. Schiro Harvey K.  A Healthy Food Guide for People on Dialysis.  2nd ed.  Chicago, Ill: Renal Practice Group of the American Dietetic Association; 2002.

MEAL PATTERNS USING HEALTHY FOOD GUIDE (SAMPLE)

Sample Meal Pattern for CKD (Pre-ESRD)
Based on 70 kg reference person

Food Choice	Number of Choices	Breakfast	Noon	Evening
High-Protein Choices	3	1	1	1
High-Protein, High Phosphorus Choices	1	1
Vegetable Choices
Group 1	1		1
Group 2	1		1
Group 3	1			1
Bread, Cereal and Grain Choices	8	3	2	3
Fruit Choices
Group 1	1			1
Group 2	1		1
Group 3	1	1
Calorie and Flavoring Choices	6-7	2-3	2	2

Approximate Totals:                      
61 g Protein      
2,130 calories   
2,090 mg sodium            
2,160 mg potassium
840 mg phosphorus

Sample Meal Pattern for CKD (Dialysis)
Based on 70 kg reference person

Food Choice	Number of Choices	Breakfast	Noon	Evening
High-Protein Choices	8	2	3	3
Dairy and Phosphorus Choices	1	1
Vegetable Choices
Group 1	1		1
Group 2	2		1	1
Group 3
Bread, Cereals and Grain Choices	9	3	3	3
Fruit Choices
Group 1	1			1
Group 2	1		1
Group 3	1	1
Calorie and Flavoring Choices	6-7	2-3	2	2
Fluid Choices	3

Approximate Totals:                      
84 g Protein
2350 calories
2150 mg sodium
2220 mg potassium
1100 mg phosphorus
960 cc fluid