Kidney health is a growing public health concern in the US and worldwide. An estimated 1 in 7 adults in the US have chronic kidney disease (CKD).^1,2 Because CKD is asymptomatic at earlier stages if left undetected, it can progress to the need for dialysis due to kidney failure.³ This is a disease that progresses slowly over time, and as many as 9 in 10 people are unaware that they have CKD.²

Healthcare practitioners can help address this knowledge gap by ensuring they’re familiar with CKD risk factors and screening, as well as the dietary and lifestyle factors that can help slow or even stop its progression. Nutrition interventions, in particular, can improve patient quality of life and clinical outcomes and should be part of the conversation for every person with CKD.⁴

Understanding Chronic Kidney Disease

The kidneys play a critical role in removing waste products such as nitrogen waste (urea) and muscle waste (creatinine), and excess fluid from the body. They also produce hormones that support the production of red blood cells and calcitriol (active vitamin D), which aids in intestinal calcium absorption, balancing minerals, regulating blood pressure, and maintaining strong bones. CKD occurs when a disease or condition impairs kidney function which can happen over months or years, reducing their ability to perform the critical tasks that affect so many systems in the body. Because the development of CKD is usually gradual and often begins with few noticeable symptoms, it is classified into five stages that guide treatment and dietary/lifestyle management strategies.^5,6

Several lab tests can indicate kidney health. Serum creatinine is a waste product filtered by the kidneys, with lower levels indicating better kidney function. The estimated glomerular filtration rate (eGFR) measures how well the kidneys filter waste. eGFR values below 60 for three months (or above 60 if there’s evidence of kidney damage) suggest dysfunction, and below 15 indicate kidney failure. See the list below to see the progressive stages of CKD using eGFR. Blood urea nitrogen (BUN), evaluated with creatinine and eGFR may be used to evaluate kidney health. Kidney health can also be analyzed via urine samples, biopsies, and imaging such as MRI or CT scans.⁶

eGFR Stages of CKD⁶:

Stage 1 CKD: eGFR 90 or higher
Stage 2 CKD: eGFR 60-89
Stage 3a CKD: eGFR 45-59
Stage 3b CKD: eGFR 30-44
Stage 4 CKD: eGFR 15-29
Stage 5 CKD: eGFR Less than 15 (need for dialysis)

*To learn more about the stages and the complexities within them, visit this CKD ‘heat map’ for more information

CKD risk factors include age (more common in people 65+ years), sex (more common in women than men; 14% vs 12%), and race (most common in non-Hispanic Black and Hispanic adults; 20% and 14% compared to White adults; 12%).¹ Chronic diseases like cardiovascular disease, especially high blood pressure, and diabetes exacerbate CKD and cause it to progress.^1.2.5 With such common chronic diseases driving risk, CKD affects many people that healthcare workers may see in a wide variety of settings. 

Dietary Patterns for Kidney Health

Dietary patterns have been studied concerning CKD development over decades with significant emerging research over the past twenty years. Researchers He et al. found in a systematic review and meta-analysis (N=17 studies with 149,958 participants) that healthy dietary patterns were associated with a lower risk of CKD (OR=0.69; CI: 0.57, 0.84; P=0.0001) when comparing the highest to the lowest dietary adherence category.⁷ Healthy patterns in this study were defined as high intake of vegetables, fruits, whole grains, fish, olive oil, soy, antioxidants, and low-fat dairy. The Western dietary pattern was high in refined grains, red and/or processed meat, sweets, desserts, butter, fast food, and soft drinks. Following a Western dietary pattern was linked to a higher risk of CKD (OR=1.86; 95% CI: 1.21, 2.86; P=0.005).⁷ 

A patient diagnosed with CKD, particularly stages 1 through 3, includes common nutrition interventions that reduce sodium, saturated fats, and processed foods while increasing fruits, vegetables, plant-based proteins, and whole grains. The Mediterranean Diet, Dietary Approach to Stop Hypertension (DASH), and plant-based dietary patterns may support people with CKD looking for guidance on what types of foods and recipes to focus on.^8,9 There are some specific dietary considerations for people with CKD, but it’s important to remember that these recommendations change as CKD progresses to later stages and should be personalized to each patient’s unique needs.^8,9 

Protein

People with CKD stages 1 and 2 likely don’t need to restrict protein and can consume a normal amount (0.8g protein/kg body weight/day). People with CKD 3-5 not on dialysis – or those with stage 2 who have protein in their urine – may need to limit their protein intake to 0.6 – 0.8g protein/kg body weight/day. When patients are on dialysis, their protein needs may increase to 1-1.2g/kg body weight/day because dialyzing removes protein waste and albumin from the blood, and these patients are at increased risk of muscle wasting due to the protein removed during their treatment.^8,9 It’s important to know that eating a high-protein diet doesn’t cause CKD, and protein often doesn’t need to be restricted until the later stages of CKD.¹⁰ Because of the nuances of protein and other nutrients with CKD, it’s important that your patients are working with healthcare providers who specialize in kidney health.

Nutrients: Sodium, Phosphorus, Potassium, Fluid

CKD diets, especially at later stages, are notoriously restrictive, with complex sodium, potassium, phosphorus, and fluid restriction recommendations, leading to frustration and non-compliance.¹¹ The most recent updates to the National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) Clinical Practice Guidelines for Nutrition in Chronic Kidney Disease recommend a personalized approach to dietary changes based on blood testing for each patient.^8,9 Keeping foods like fruits, vegetables, whole grains, legumes, and nuts in the diet as much as possible is important for cardiovascular health and blood glucose control, though many of these foods contain potassium and phosphorus.^8,9

Sodium recommendations for people with CKD aren’t different from the general recommendations – 2300mg per day (or <1500 mg/d if a patient has high blood pressure).^12,13 Limiting sodium may help patients who are experiencing swelling/edema or shortness of breath due to fluid overload. Fluid may need to be restricted at later stages (4 and 5) of CKD as the kidneys are less able to balance fluid and remove waste from the blood. Common fluid restrictions are 1000-1500 mL/day and should be personalized to each patient based on their health and kidney treatment plan.¹⁴

Regarding potassium, most people in the early stages of CKD do not have problems with this nutrient. Because high or low blood levels are dangerous for a patient’s health, healthcare providers should be prepared to educate on foods that can help boost potassium levels – or high-potassium foods to avoid if blood levels run high.^8,9,15 Foods highest in potassium include potatoes, squash, dried apricots, lentils, raisins, oranges/orange juice, and beans among many other whole foods though these are healthful foods that should be kept in the diet unless a patient is instructed to reduce their intake based on blood labs.¹⁶

At later stages of CKD (4 and 5), phosphorus might need to be limited, or a client’s medical team may advise phosphorus-binding medications.¹⁷ Typically, foods that contain phosphorus, like whole grains, nuts, seeds, and beans, can still be included because absorption is limited in plant foods. Due to natural phytate content, only about 50% of the phosphorus from plant foods is absorbed compared to up to 100% of phosphorus from meat, fish, dairy, and foods with phosphorus additives.^17-19 Patients struggling with high serum phosphorus levels should also speak with their kidney care team to discuss which, if any, phosphorus additives they should limit or avoid. 

Takeaways for Healthcare Providers

Healthcare providers may encounter CKD anywhere they see patients or clients; it’s a very common condition. Being aware of the risk factors, including age, sex, race, and other chronic diseases that often accompany CKD, is an important step in being able to identify a patient who may need screening or education. Ensuring that your patients are talking to their doctors to include a urinalysis and an eGFR in their routine blood test, in addition to managing conditions like diabetes and high blood pressure, are important preventive strategies. 

Helping your patients with CKD meet their nutritional needs is a critical role that healthcare professionals play in this complex condition. For patients undergoing dialysis, plant-based nutritional supplements provide a convenient, on-the-go protein source, while people in earlier stages of CKD may also benefit from these supplements when nutrition is compromised because vegetarian protein has been shown to potentially slow disease progression.^{20, 21}

The National Kidney Foundation has developed a short kidney risk quiz that anyone can take to better understand their personal risk factors for CKD: MinuteForYourKidneys.org 

References:

1. Centers for Disease Control and Prevention. Chronic Kidney Disease in the United States, 2023. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention. Updated May 15, 2024. https://www.cdc.gov/kidney-disease/php/data-research/index.html#:~:text=More%20than%201%20in%207,are%20estimated%20to%20have%20CKD.&text=As%20many%20as%209%20in,not%20know%20they%20have%20CKD.
2. National Institute of Diabetes and Digestive and Kidney Diseases. Kidney Disease Statistics for the United States. National Institute of Diabetes and Digestive and Kidney Diseases. Reviewed September 2024. https://www.niddk.nih.gov/health-information/health-statistics/kidney-disease
3. Luyckx VA, Al-Aly Z, Bello AK, et al. Sustainable development goals relevant to kidney health: an update on progress. Nature Reviews Nephrology. 2021;17(1):15-32.
4. Wang AY, Okpechi IG, Ye F, et al. Assessing global kidney nutrition care. Clinical Journal of the American Society of Nephrology. 2022;17(1):38-52.
5. National Kidney Foundation. Chronic Kidney Disease (CKD). National Kidney Foundation. Reviewed September 11, 2023. https://www.kidney.org/kidney-topics/chronic-kidney-disease-ckd
6. National Kidney Foundation. Tests to Check Your Kidney Health. National Kidney Foundation. Reviewed June 1, 2023. https://www.kidney.org/kidney-topics/tests-to-check-your-kidney-health
7. He LQ, Wu XH, Huang YQ, Zhang XY, Shu L. Dietary patterns and chronic kidney disease risk: a systematic review and updated meta-analysis of observational studies. Nutr J. 2021;20(1):4.
8. Kistler BM, Moore LW, Benner D, et al. The International Society of Renal Nutrition and Metabolism Commentary on the National Kidney Foundation and Academy of Nutrition and Dietetics KDOQI clinical practice guideline for nutrition in chronic kidney disease. Journal of Renal Nutrition. 2021;31(2):116-20.
9. Navaneethan SD, Zoungas S, Caramori ML, et al. Diabetes Management in Chronic Kidney Disease: Synopsis of the KDIGO 2022 Clinical Practice Guideline Update. Ann Intern Med. 2023;176(3):381-387.
10. Ko GJ, Rhee CM, Kalantar-Zadeh K, Joshi S. The Effects of High-Protein Diets on Kidney Health and Longevity. J Am Soc Nephrol. 2020;31(8):1667-1679.
11. Nyma Z, Kitaoka K, Yano Y, Kanegae H, Bayaraa N, Kishi S, Nagasu H, Nakano T, Wada J, Maruyama S, Nakagawa N. Evaluating the associations between compliance with CKD guideline component metrics and renal outcomes. Scientific Reports. 2024;14(1):11481.
12. National Kidney Foundation. How Much Sodium is Safe for Kidney Patients? Reviewed January 5, 2022. https://www.kidney.org/news-stories/how-much-sodium-safe-kidney-patients
13. American Heart Association. Shaking the Salt Habit to Lower High Blood Pressure. American Heart Association. Reviewed May 9, 2024. https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/shaking-the-salt-habit-to-lower-high-blood-pressure.
14. Lambert K, Neale E, Nichols L, et al. Interventions for improving adherence to dietary salt and fluid restrictions in people with chronic kidney disease (stage 4 and 5). Cochrane Database Syst Rev. 2022;2022(10):CD015181.
15. National Kidney Foundation. Potassium and Your CKD Diet. National Kidney Foundation. Reviewed May 5, 2023. https://www.kidney.org/kidney-topics/potassium-your-ckd-diet?utm_source=organic&utm_medium=blog&utm_campaign=a-z&utm_term=potassium&utm_content=kidney-diet-fact-fiction
16. Office of Dietary Supplements, National Institutes of Health. Potassium: Fact Sheet for Health Professionals. National Institutes of Health. Updated June 2, 2022. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
17. Biruete A, Gallant KM, Lloyd L, et al. ‘Phos’tering a clear message: The evolution of dietary phosphorus management in chronic kidney disease. Journal of Renal Nutrition. 2023.
18. National Kidney Foundation. 6 Kidney Disease Diet Myths. National Kidney Foundation. Reviewed May 18, 2023. https://www.kidney.org/news-stories/6-kidney-disease-diet-myths
19. Wang M, Zhang J, Kalantar-Zadeh K, Chen J. Focusing on phosphorus loads: from healthy people to chronic kidney disease. Nutrients. 2023;15(5):1236.
20. Krefting J. The appeal of pea protein. Journal of Renal Nutrition. 2017;27(5):e31-3.
21. Clegg DJ, Gallant KM. Plant-based diets in CKD. Clinical journal of the American Society of Nephrology. 2019;14(1):141-3.