Diabetes, in general, is a disorder in which the blood glucose level or blood sugar level is too high. In a normal human, these levels are controlled by the hormone Insulin. Insufficient levels of insulin or complete absence of insulin leads to an uncontrolled rise in blood glucose levels. If diabetes remains uncontrolled for longer, it gives rise to serious complications and affects all normal body functions directly or indirectly.
Diabetic nephropathy or diabetic kidney disease is one of the most serious complications that arise along with uncontrolled diabetes mellitus. Both Insulin Dependent Diabetes Mellitus (IDDM) and Non-Insulin Dependent Diabetes Mellitus (NIDDM) can lead to diabetic nephropathy if proper management is not done. Diabetic kidney disease is the leading cause of End-Stage Renal Disease (ESRD).
How does diabetes cause kidney disease?
Kidneys perform the vital function of filtration. During the process excess amount of any substance present in the blood is excreted out in urine, with continuous high blood sugar level in uncontrolled diabetes, the filtration ability of the kidneys gradually falls, this causes defective membrane permeability.
As a result, the membrane becomes permeable to proteins (which must remain in the blood) and they are excreted out. In the initial stages, the blood protein albumin is found in small quantities in urine. This condition is known as “Microalbuminuria”.
The presence of albumin in the urine is the first indicator that diabetes has started affecting kidneys. If this remains untreated, greater quantities of albumin are excreted out leading to “Macroalbuminuria”.
Diabetic Nephropathy progresses slowly. Following are the symptoms that appear with time, if proper measures are not taken.
|Increase in size and activity of the kidney||At diagnosis||Enlarged kidney, higher blood flow, and Increased filtration|
|Changes to the kidney tissue||2-5 years||Thickening of the basal membrane|
|Onset of nephropathy||5-15 years||Albuminuria, high blood pressure|
|Clinical manifestations of Nephropathy||10-25 years||Macroalbuminuria, High blood pressure|
|Renal insufficiency||15-30 years||Rise in serum creatine. Permanent HTN|
Risk Factors for developing Diabetic Kidney Disease:
It is important to know, not all diabetic patients have kidney disease but, some conditions that are potential risk factors include:
- High blood pressure
- Cardiovascular Disorders
- Uncontrolled Diabetes Mellitus
- High salt consumption
- Physical Inactivity
Nutritional Guidelines for Diabetic Nephropathy:
Although diabetic nephropathy cannot be completely cured, its progression can be slowed down with the help of Medical Nutrition Therapy. Nutrition management for diabetes includes management of blood glucose level, blood lipids, hypertension, a healthy body weight. But these targets are harder to achieve for patients with diabetic nephropathy.
Diet therapy is affected by individual effects of nutrients on kidney functions and renal hemodynamics. Diabetic kidney disease requires very strict observation of dietary recommendations for carbohydrates, proteins, fats, and management of electrolytes depending on their individual kidney function.
Weight management and physical activity have also been proved to have a great role. Furthermore, dietary recommendations may differ with different stages of DKD.
Some common foods to avoid in Kidney Disease and Diabetes are listed here:
How much glucose is recommended in patients with kidney disease and diabetes:
A very important tool for good diabetes therapy is the maintenance of blood glucose level below renal threshold (250mg/dl) so that it does not pass in the urine. The characteristic features of patients with kidney disease are insulin resistance and glucose intolerance. For the management of glucose, the target of HbA1c should be <7 %.
Blood glucose levels in the body are affected by the amount and type of carbohydrates. For better management of blood glucose, foods with a glycemic index <55 must be consumed. Low GI (glycemic index) foods include whole grains, cereals, carrots, broccoli, celery, cauliflower, etc.
Eat foods with a low Glycemic Index
How much dietary fiber is recommended in patients with kidney disease and diabetes:
Dietary fiber lowers blood sugar in diabetic patients. Soluble and Insoluble fiber reduces the digestion time of carbohydrates and hence aid in improving insulin sensitivity. The FDA recommends 14g of fiber per 1000kcal and this amount can be increased up to 35g according to the patient’s needs.
Daily Fiber Intake should range from 14 G to 35 G
Among the Foods to Avoid in Kidney Disease and Diabetes, Dietary Restriction of Proteins is very important:
Protein is the major regulatory factor in nephropathy. Reducing the amount of dietary protein intake results in reduced protein excretion and a regulated glomerular filtration rate is achieved gradually. Many experiments done on animals and humans have shown lower protein excretion in urine when a low protein diet is consumed, ultimately causing a delay in the progression of diabetic nephropathy.
Most of the patients do not focus on their dietary patterns and rather consume excessive quantities of carbohydrates and proteins, this excessive intake is harmful and needs to be adjusted in every diabetic patient with or without any comorbid condition.
Avoid Excessive Carbohydrates and Proteins
The recommended protein-restricted diet of 0.6-0.8 g/kg protein in a day aids in improving GFR to some extent. For Diabetic nephropathy patients with disease stage 1 or 2, 0.8 g/kg per day is generally recommended, which means, for a person with an ideal body weight of 68kg the recommended daily percentage of protein will be 68 × 0.8 = 54 grams of protein.
For a person with disease stage, 3 or above the recommended value of dietary protein is 0.6g/kg so, with a person weighing 68 kg, the recommended protein amount will be 68 × 0.6= 40 grams protein per day Although, the recommended protein amount for dialysis-dependent patients is about 1.2g/kg (81 grams) due to dialysis-induced protein loss.
Protein cannot be completely excluded from the diet but patients with diabetic kidney disease need to carefully monitor their protein intake according to their disease stage, glycemic control, and overall nutritional status. Patients must be given proper counseling about medical nutrition therapy. Plant-based proteins should be used instead of animal proteins.
In the case of animal protein, lean meat from fish and poultry is recommended. Some amount of protein is also present in grains and starchy vegetables so it must be carefully adjusted within the recommended amount of protein.
Recommended Protein intake is 0.6 – 0.8 G/kg/day
Fruits and vegetables to use and avoid in patients with Kidney Disease and Diabetes:
Fruits and vegetables with low potassium, phosphorus, and sodium are preferred in DKD patients.
- Some of the fruits that are not harmful to DN patients include Apples, Red Grapes, Strawberries, Cherries, Pear, Peach, Plum, Apricots, and Watermelon. While, fruits that need to be restricted include Oranges (Due to high amount of potassium), Mangoes, Dates, Bananas, and all canned fruits
- Vegetables are mainly adjusted as the biochemical test results of a patient’s potassium and phosphorus concentration in blood. Vegetables good for DN patients include Cauliflower, Cabbage, Cucumber, Eggplant, Broccoli, Carrots, etc.
- Fruits and vegetables need to be adjusted carefully according to the patient’s blood concentration of potassium and phosphorus, Malnutrition and muscle wasting can occur if the patient does not get a proper nutrient-dense diet.
- Due to the protein restriction, carbs need to be supplied in adequate quantities to meet the extra requirements of the body.
Fats to use and avoid in patients with kidney disease and diabetes:
The optimal amount of fats for DKD patients has not been defined yet. The general guidelines suggest that reduced intake of saturated fat and trans-fat contributes to a reduced risk of cardiovascular diseases.
In DKD (diabetic kidney disease) saturated fats are limited to <7% of total calories. In comparison to the quantity of fat, its quality has a greater effect. Poly-unsaturated fatty acids (PUFA’s) and Mono-unsaturated fatty acids (MUFA’s) are known to have a beneficial impact on the control of hypertension and dyslipidemia. In recent studies, it has been observed that higher dietary intake of PUFA’s lowers the incidence of End-Stage Renal Disease (ESRD).
Phosphorus and its impact on DKD:
Phosphorus is a mineral that is found in bones and teeth along with Calcium. With impaired renal function, the excretion rate of phosphorus is decreased which results in an increased amount of phosphorus in the blood.
Therefore, intake of foods with high phosphorus content must be reduced. Phosphorus intake for Diabetic kidney disease patients must be 800-1000mg/day, to prevent hyperphosphatemia. Foods with a High protein to phosphorus ratio should be restricted.
Some of the products with high phosphorus content include:
- Milk and milk products
- Soft drinks and other beverages
- Frozen and Canned products
- Processed food items.
Vegan diet consumption must be encouraged and plant protein should be preferred because only 50% of phosphorus is absorbed from vegetable sources.
Sodium and Other Minerals to use and avoid in patients with diabetic kidney disease:
Sodium restriction in Diabetic Kidney Disease (DKD) is similar to that of Chronic Kidney Disease (CKD), a low amount of sodium has been proved to be beneficial as it affects blood pressure, the efficiency of anti-hypertensive medication, and proteinuria.
Dietary sodium intake for DKD patients is 1,500-2,000 mg/day. Sodium restriction is categorized as:
- Mild restriction (1,500-2,000mg/day),
- Moderate (1,000-1,500 mg/day) and
- Extreme (<1,000mg/day)
according to the patient’s blood pressure.
Calcium intake should be <2000mg/day inclusive of supplements
Avoid drugs that may damage your kidneys:
It is the poisonous effect of some drugs or medications on kidney function. Patients with Diabetic Nephropathy must avoid nephrotoxic agents like Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and Cyclooxygenase 2 (COX-2) inhibitors. These drugs are known to cause a decreased glomerular filtration rate (GFR).
Dietary Guidelines for Diabetic Kidney Disease
- Proper glycemic control must be done in patients with DN. Hyperglycemia plays a key role in the development of diabetic nephropathy, glucose management within time can slow the progression of the disease.
- Small meals must be taken as compared to large meals to avoid increased blood sugar levels.
- Meal plans should be carefully made by a Registered Dietitian so that carbohydrates, proteins, and fats are in the right proportions.
- Carbohydrate amounts should be kept constant in all meals to avoid an increase in blood sugar levels.
- Meals and Medication must be coordinated to avoid hyperglycemia and hypoglycemia.
- The amount of minerals must be carefully focused in every meal that is planned.
Dietary patterns for patients with Diabetic Kidney Disease to follow:
Diet therapy in patients with diabetic nephropathy plays a substantial role in delaying the progression of the disease. The food and nutrition-related knowledge of patients is often poor which leads to problematic management of disease and an increased risk of complications. A diabetic diet ensures the consumption of a healthy diet, whereas a Diabetic nephropathy diet is designed to slow down the progression of renal disease, hypertension, hyperlipidemia, and control of blood glucose levels along with careful monitoring of sodium and potassium levels.
Experiments and research suggest that focusing on diet patterns for managing chronic diseases is more beneficial than focusing on the intake of individual nutrients.
The Mediterranean diet includes the enhanced intake of complex carbohydrates, whole grains, fruits and vegetables, seeds, beans, fish, and olive oil. Intake of trans fat products and other animal proteins along with full-fat dairy products is decreased. These dietary patterns are a new approach for the prevention of Diabetic Nephropathy
A Sample Diet Plan for Diabetic Patients with Kidney Disease:
|White Bread + Egg white
|1 glass||Pomegranate juice||80|
|1 disc size
|1 glass||Skim milk||100|
Total calories: 1286 kcal
- The above-mentioned diet chart must be followed with all foods cooked in olive oil along with a restricted amount of sodium and trans fats.
- Calorie intake is less due to weight management in diabetic patients.
- Small meals with short intervals must be beneficial for the proper management of the nutrition care process
- All patients must regularly monitor their glucose levels before and after taking the meals
- Biochemical tests must be done to assess the status of Albuminuria and Glomerular Filtration Rate (GFR)
- There are separate dietary management techniques for patients undergoing dialysis and those with End-Stage Renal Disease (ESRD)