Chronic kidney disease (CKD) is a chronic disease characterized by progressive kidney damage, which decreases the ability to filter waste products from the bloodstream. If the kidney damage is severe, it is called end-stage kidney disease (ESRD) or kidney failure. Diabetes and hypertension (high blood sugar levels) are CKD’s two most common causes.
CKD is a global public health burden, with 37 million people (more than 1 in 7 adults) in the U.S. alone having been diagnosed with CKD.
Damage to the kidneys caused by CKD is irreversible; however, the use of nutritional therapy as an approach to slow disease progression and reduce uremia has been recommended for years.
- During CKD progression, nutritional requirements and utilization of nutrients change significantly.
- The required intake of cholesterols, minerals, vitamins, and polyunsaturated fatty acid (PUFA), is associated with the different stages of CKD.
- Reducing protein intake may reduce CKD progression by lowering the production of blood urea nitrogen.
- Strong evidence continues to support the importance of optimizing the diet in the prevention and progression of CKD.
Connection Between Nutrition and Kidney Health
Studies have proven that CKD patients have different dietary patterns and requirements than the general population. This is due to CKD interfering with the body’s biological and physiological mechanisms, such as blood pressure regulation, removal of waste and toxins, pH and electrolyte balance, hormonal regulation, and vitamin D metabolism.
Relationship between key nutrients and the kidneys:
- Vitamin D. The primary role of Vitamin D is to activate calcium reabsorption, but as CKD progresses, alterations to this mechanism occur, resulting in it being less effective. In ESRD patients, low active vitamin D levels may be associated with reduced bone mineral density and increased bone reabsorption.
- Protein. Data suggests that continuously high intakes of protein may lead to increased pressure and glomerular morphologic changes in the kidney, negatively affecting its ability to function.
- Phosphorus. Phosphorus is vital in bone formation, energy production, and acid-base balance. Phosphorus balance is maintained by the excess being removed from the body via urine. In CKD, reduced kidney function prevents the excess phosphorus from being removed.
- Potassium. This mineral has many biological functions and is essential for cardiac function, glucose metabolism, muscle contractions, and neural transmission. If potassium balance is disrupted, a person may be at risk of developing hyperkalemia, a condition that is often seen in CKD patients.
- Sodium. Increased sodium levels are a known cause of hypertension and may lead to heart failure. Hypertension is also a known risk factor for CKD and cardiovascular disease progression.
- Calcium. Calcium balance is controlled by the absorption of calcium in the intestines, kidney reabsorption, and calciotropic hormones. When the kidneys cannot reabsorb calcium, a chronic calcium deficiency may result, increasing the person’s risk for osteitis and hyperthyroidism. Excessive calcium due to the kidneys not being able to remove the excess may increase the risk for calcification, resulting in comorbidities.
Thus CKD patients’ diets may need to be modified to help the kidneys maintain the biological and physiological mechanisms that have been disrupted.
Current diets being investigated for their role in delaying CKD progression include:
- The Mediterranean diet.
- The Dietary Approaches to Stop hypertension.
- The whole foods plant-based diet.
Diet for CKD
The most favorable diet for CKD patients is dependent upon individual estimated glomerular filtration rate (eGFR), the type of kidney disease, and if other comorbidities such as heart failure, hypertension, or diabetes are present.
The diets discussed below are not meant to replace your dietician or doctor’s recommendations, but rather to highlight the role nutrition plays in the chronic kidney disease spectrum.
What is a Kidney-friendly diet?
A kidney-friendly diet is designed to help manage and slow down the progression of damage to the kidneys. The diet/eating plan works to prevent certain minerals, such as sodium (salt), from building up in the body, especially when your kidneys are unable to filter excess minerals and waste products out of the body.
The main goals of a kidney-friendly diet are to provide the patient with enough energy to continue day-to-day tasks, prevent infection from occurring, build muscle, and maintain a healthy weight (determined by your healthcare professional).
A kidney-friendly diet is also implemented to help prevent or control comorbidities such as diabetes and hypertension (high blood pressure), as they may increase CKD progression.
Tips for maintaining a kidney-friendly diet
Your kidney-friendly diet may change over time, depending on your needs and stage of kidney function. However, it is always recommended to consume macronutrients (protein, carbohydrates, and fats).
Tips for maintaining a kidney-friendly diet include:
- Eat the right types and amounts of protein
- Choose heart-healthy types of fats
- Select whole-grain carbohydrates
- Make sure you eat the right amount of calories
- Choose and cook foods with less salt (sodium)
- Control your portion size
- Choose foods with the right amount of potassium
- Reduce the amount of phosphorus
- You may need to limit the amount of fluids
You can discuss quantities of your kidney-friendly diet with your dietician and physician.
End-Stage Renal Disease Diet
ESRD requires complex dietary management, which includes the adjustment of dietary intake of sodium, protein, phosphorus, potassium, fluids, magnesium, vitamin D, calcium, and other vitamins and trace minerals.
Due to your kidneys no longer being able to clear the waste and excess fluid by themselves, you may undergo hemodialysis, where a dialysis machine and a filter called an artificial kidney (dialyzer) are used to clean your blood. If you are on hemodialysis, you may need a diet to help limit your sodium, potassium, phosphorus, and fluid intake.
If you are an in-clinic dialysis patient receiving treatment three times a week, you may need a stricter kidney-friendly diet, as there is an increased time between treatments (blood being cleaned). Waste and fluids could build up in your blood, if not managed. If you are an at-home dialysis CKD patient with everyday daily treatments, your diet may not need to be as strict.
Peritoneal dialysis diet
Peritoneal dialysis is a treatment used for kidney failure, which uses the lining of your abdomen (peritoneum) to filter the blood inside your body. Compared to a general hemodialysis diet, you may be able to increase your consumption of sodium, phosphorus, potassium, and fluids. You may need to increase protein intake, as peritoneal dialysis works continuously to remove waste and excess fluid from your blood. This keeps it from building up in your blood, which is commonly observed in hemodialysis patients between treatments.
Talk to your dietitian or care team about a kidney-friendly diet that suits your dialysis treatments.
Dietary Steps for CKD Patients With Diabetes
If you are a CKD patient with diabetes, your dietician or care team will work with you to create a diet plan that controls your blood sugar while limiting or avoiding nutrients that cause disease progressions.
If you have late-stage CKD or ESRD with diabetes and are on dialysis, you will need to talk to your dietitian, as your nutrition needs will change. You may find that you will need to eat more protein, and your blood sugar levels actually get better. However, blood sugar may increase or spike when you are on dialysis due to the fluid used during dialysis containing glucose (sugar). Your doctor should monitor your blood glucose levels closely to help manage it and prevent hemodialysis-induced hypoglycemia (low blood sugar level).
If you have any questions or need help sticking to or understanding your diet plan, talk to your dietitian or care team, and they will walk you through your diet plan and help you with meal preparations so that you are empowered and can take control of your nutrition management.
Panoramic Health is a physician-led value-based care platform that has 14+ years of experience in chronic kidney disease. Our clinical expertise allows us to understand CKD from all angles and address patient care holistically.
Our patient engagement is a core focus, as this leads to improved quality of life and equips patients to take the necessary steps to prevent their kidney disease from progressing. Our comprehensive care model offers patients holistic care management with services such as pharmacy, nutrition, SDOH services, and PCP coordination, which are all customized to their disease stage and risk profile.