"Kidney" is important: Dietary guidelines for patients with uremia

Author: Yang Li, attending physician, Nanfang Hospital, Southern Medical University; Liu Hongfa, deputy chief physician, Nanfang Hospital, Southern Medical University; Reviewer: Xie Di, chief physician, Nanfang Hospital, Southern Medical University

Uremia is a serious condition of kidney disease that develops to the end stage. The kidney function is severely damaged and cannot excrete toxic substances (such as urea, creatinine, etc.) in the body normally. Uremia is mainly treated with dialysis and kidney transplantation, but these methods cannot completely replace the function of the kidneys. Therefore, reasonable adjustment of diet has become one of the key factors in maintaining the patient's quality of life and delaying the progression of the disease.

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◆Theoretical basis of dietary principles for patients with uremia

1. Changes in protein metabolism The kidney function of patients with uremia is impaired, which has a significant impact on nutritional metabolism. On the one hand, protein metabolites cannot be effectively excreted, and excessive protein intake will increase the burden on the kidneys; at the same time, the amino acids produced by protein degradation increase, which in turn stimulates the production of glucose. On the other hand, patients lose a lot of protein and amino acids during dialysis, so they need to properly supplement high-quality protein to meet the body's needs.

2. Calorie demand: Uremic patients have impaired renal function and increased nitrogen metabolites. Adequate calorie intake can reduce protein decomposition, thereby reducing the production of nitrogen metabolic waste in the body. Insufficient calories can lead to malnutrition, while excessive intake can induce atherosclerosis or hyperlipidemia.

3. Electrolyte balance and diet control

(1) Potassium control: Uremic patients have a reduced ability to excrete potassium, which can easily lead to hyperkalemia and possibly cardiac arrest. Therefore, it is very necessary to limit potassium intake.

(2) Phosphorus control The kidneys of patients with uremia have reduced ability to regulate phosphorus and calcium, and blood phosphorus levels are prone to increase. Hyperphosphatemia can lead to complications such as renal osteodystrophy, skin itching, and vascular calcification. Therefore, phosphorus intake needs to be controlled.

(3) Sodium control: Patients with uremia should strictly control their sodium ion intake to reduce the risk of edema and hypertension.

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◆Basic principles of dietary management for patients with uremia

1. Control protein intake. Uremic patients need to limit protein intake. It is generally recommended to consume 0.6-0.8g per kilogram of body weight per day. Hemodialysis patients are recommended to consume 1.2g/kg per day, and peritoneal dialysis patients are recommended to consume 1.2-1.5g/kg per day to reduce the generation of urea and other nitrogenous wastes.

2. Control sodium salt intake. Excessive intake of sodium salt can cause edema and high blood pressure, so the use of salt should be limited. It is recommended that the daily intake should not exceed 2g.

3. Control the intake of potassium and phosphorus. Due to impaired renal function, the ability of uremia patients to excrete potassium and phosphorus is reduced. Excessive intake may lead to hyperkalemia and hyperphosphatemia. Therefore, the daily potassium intake of uremia patients should be controlled within 3g, and high-phosphorus foods should be avoided.

4. Appropriate energy intake Patients can increase the intake of carbohydrates and healthy fats to ensure adequate calories and balanced nutrition, and avoid falling into the misunderstanding of dieting.

5. Maintain adequate water intake. Uremic patients have reduced urine output and need to strictly control water intake to avoid swelling, high blood pressure, etc. Usually, the amount of liquid taken orally is approximately equal to the daily urine output plus 500ml. It should be adjusted according to the doctor's advice to avoid excessive intake.

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◆Food choices suitable for patients with uremia

1. High-quality protein sources Uremia patients should pay attention to the quality and source of protein. High-quality protein (such as animal protein) can provide essential amino acids while reducing the metabolic burden associated with uremia. Recommended sources include animal proteins such as eggs, fish, lean meat, and poultry, as well as plant proteins such as tofu and beans (but pay attention to the phosphorus content).

2. Sodium salt substitutes To reduce sodium salt intake, patients can try to use some sodium-free spices and condiments to increase the flavor of food. Recommended substitutes include herbs (such as rosemary, thyme), lemon juice or vinegar, garlic and ginger. When cooking, use less salt and add salt when the dish is cooked; when dining out, use boiled water to dilute the salt in the food before eating.

3. Control of potassium and phosphorus Hyperkalemia and hyperphosphatemia are common complications in patients with uremia. Therefore, special attention should be paid to the intake of potassium and phosphorus. Low-potassium foods such as apples, blueberries, peaches, white rice, white bread, etc. are recommended; high-potassium foods such as bananas, oranges, potatoes, spinach, etc. are avoided. Low-phosphorus foods such as refined grains (such as white rice, white bread), vegetables (such as lettuce, carrots), etc. are recommended; high-phosphorus foods such as egg yolks, dried lotus seeds, offal, etc. are avoided. At the same time, appropriately increasing calcium intake (such as fresh milk, cheese, yogurt, etc.) can help lower blood phosphorus levels.

4. Management of water intake Water intake needs to be adjusted according to the patient's urine volume and doctor's advice. Patients with uremia may experience edema, so they need to be cautious when drinking water. The recommended daily water intake is determined according to the doctor's specific instructions, usually 1 to 2L. Avoid beverages containing caffeine and alcohol, as they may cause dehydration.

5. Ensure sufficient calories. The main source of calories is carbohydrates. Take in enough carbohydrates to provide the calories needed by the body. You can choose high-calorie, low-protein foods, such as potatoes, taro, lotus root, pumpkin, etc. Try to eat mainly grains, eat more green leafy vegetables and fruits, and eat less animal fat and sucrose foods. This can effectively utilize the ingested protein, avoid protein being decomposed due to providing calories, and increase the production of urea nitrogen.

The diet of patients with uremia needs to be adjusted according to individual conditions. The patient's diet plan should be personalized by a doctor or nutritionist based on their specific condition, nutritional status, and taste preferences. In addition, attention should be paid to controlling food intake to avoid excessive eating that increases the burden on the body.

References:

[1]Campbell K. Nutritional management in pre-dialysis chronic kidney disease: an investigation of methods for nutritional assessment and intervention in pre-dialysis chronic kidney disease[J]. 2022.

[2] Chinese Journal of Clinical Nutrition and Nutritional Therapy for Chronic Kidney Disease (2021 Edition)

[3] Practical Internal Medicine (16th edition)

[4] Shen Yan. Effects of different vascular accesses on micro-inflammatory factors and renal anemia in patients with maintenance hemodialysis[J]. Contemporary Medicine, 2023, 29(11):104-106.

[5] Liang Xiao. Study on the improvement of physical and mental health of maintenance hemodialysis patients by standardized dietary care[J]. Health World, 2021, 000(016):59.

[6] Lian Jingying, Huang Shuirong, Zhang Qiongjiao. Effect of dietary guidance and nursing on calcium and phosphorus metabolism in patients with maintenance hemodialysis[J]. China Pharmaceuticals, 2020, 29(S02):185-186.

[7] Tao Lijuan, Xu Hongmei, Chen Huirong, et al. Analysis of the effects of intensive nutritional intervention on maintenance hemodialysis patients[J]. Medical Diet Therapy and Health, 2022(002):020.