What can you eat to support your kidney health?

Monitoring kidney function is often part of routine medical care to help support overall health. Because the kidneys play many important roles in the body, changes in kidney function can affect other systems as well. Identifying changes early allows your healthcare team to guide next steps.

Nutrition plays a meaningful role in both supporting kidney health and managing chronic kidney disease. Below, we’ll walk you through what the kidneys do, how kidney function is categorized, and what balanced eating can look like at different stages.

Key Takeaways: Healthy Kidney Nutrition

• Your kidneys filter waste, regulate fluids, balance electrolytes, support blood pressure, and activate vitamin D.
• Kidney function is commonly measured using creatinine and estimated GFR.
• Diabetes and high blood pressure are two leading contributors to chronic kidney disease.
• Managing blood sugar and limiting sodium can help protect kidney function.
• Fibre-rich, Mediterranean-style eating patterns are supportive for overall and kidney health.
• There is no one-size-fits-all kidney diet — nutrition recommendations depend on your stage of kidney disease, lab values, medications, and overall health.

What are the kidneys and why are they important?  

The kidneys are two organs located on each side of the backbone. They have a bean shape and are approximately the size of your fist.  

The kidneys are important for: 

• The elimination of drugs, poisons and metabolic wastes mainly related to the degradation of protein
• The regulation of the body’s fluid by retaining water into the body or excreting more water into the urine
• The regulation of the metabolic pH and electrolytes
• The regulation of the blood pressure
• The production erythropoietin, a hormone responsible for the stimulation of the bone marrow to produce red blood cells
• The activation of vitamin D

Inside the kidneys, there are nephrons which are responsible for the above roles. Each of the kidney contains approximately 1 million nephrons. As the function declines, the number of nephrons declines, which makes it harder for the kidneys to achieve their roles.

In order to estimate the function of the kidneys, creatinine, a waste product found in the blood, is being monitored. Based on the creatinine level, the Glomerular Filtration Rate (GFR) is estimated.

Below are the chronic kidney disease categories based on the GFR levels: 

• Stage 1 (GFR >90): Minimal kidney damage, no intervention is required 
• Stage 2 (GFR 60-89): Mild kidney damage, nutrition intervention focuses on the prevention of further decline in kidney function 
• Stage 3 (GFR 30-59): Moderate kidney damage, nutrition intervention focuses on the prevention of further decline in kidney function AND the treatment of the comorbidities 
• Stage 4 (15-29): Severe kidney damage, nutrition intervention focuses on the treatment of the comorbidities AND transplant or dialysis is being considered.
• Stage 5 (GFR <15): Kidney failure. Dialysis or transplant may be required, and care is guided closely by a nephrology team.

What diet should you follow when you have a low kidney function? 

The honest answer? It depends.

There is no one “kidney diet” that works for everyone. Kidney health is personal. Depending on your stage of kidney disease, lab values, medications, and other health conditions, nutrients like protein, potassium, phosphorus, sodium, and fluids may need adjustment — or may not need significant changes at all.

That’s why individualized guidance matters. A Registered Dietitian can help you create a plan that supports your kidney health while still allowing you to enjoy food and live fully.

Manage your blood sugar

If you have diabetes, make sure your blood sugar stays within the normal range. Hyperglycemia, high blood sugar, is the #1 cause of decline in kidney function.  

Lower your sodium intake

The second cause of chronic kidney disease is hypertension. A high blood pressure can damage or weaken the blood vessels in the kidneys resulting in a decline in function. Did you know that roughly 80% of the excess in sodium we eat is from the food we bring from the grocery and not the salt added while cooking? That means that the most control we have is while making choices at the grocery store; choosing lower or no added salt products and choosing fresh produce and proteins can have a huge impact on your health.  

Increase your fibre

Fibre is important for good digestion but also to lower the blood cholesterol which ultimately has an impact on the heart health and blood pressure. As described earlier, a high blood pressure is one of the main causes of chronic kidney diseases.  

Examples of fibre sources:

• Oats (rolled or steel-cut)
• Oat bran
• Barley
• Quinoa
• Brown rice
• Whole wheat pasta
• Whole grain bread (look for 3g+ fibre per slice)
• High-fibre cereals (check label: 5g+ per serving)

A note about the Mediterranean Diet to prevent kidney problems

The Mediterranean diet has been shown to have a positive impact on the prevention of the decline in kidney function as shown in this handout recently released by BC Renal, the British Columbia Kidney Agency.

This style of eating emphasizes fresh foods, more specifically the daily intake of whole grains, fruits, vegetables and unsaturated fats such as olive oil, regular intake of plant-based protein and fish/seafood and more limited intake of red meats, poultry and dairy.  

Final Note:

To go back to the “It depends” from earlier, here are the tricky things with chronic kidney disease and diets. We are all unique in how our body reacts. Therefore, nutrients such as protein, potassium and phosphorus may not need to be adjusted at all, may need to be limited or may need to be increased… and this depends on your stage of chronic kidney disease, your comorbidities and even your medication or supplements.

A medically informed registered dietitian can help individualize the diet that YOU need, one that takes into consideration your level of kidney disease, your lifestyle, and any other health conditions (like heart disease or diabetes) that may also need to be considered. 

If you or a loved one have a decline in kidney function, don’t hesitate to contact us for support in maintaining a healthy kidney diet. Getting personalized support can help you feel more confident in your food choices and support your kidney health in a sustainable way.

 This article is based on The Essential Guide for Renal Dietitians, 4th edition, 2020, Canadian Association of Nephrology Dietitians (CAND) 

Looking for support for declining kidney function?

If you or someone you care about has been told their kidney function is changing, you don’t have to figure this out alone.

Our Registered Dietitians specializing in kidney health can help you:

✔️ Understand your lab values
✔️ Clarify which nutrients matter for you
✔️ Build balanced, satisfying meals
✔️ Reduce confusion from online advice
✔️ Protect both your kidney health and your relationship with food

Book a free discovery call and let’s explore what support could look like for you.

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