Like many chronic conditions, chronic kidney disease is a nutrition-related health problem. Nutrition care in kidney disease has traditionally focused on preventing complications: potassium restriction to prevent hyperkalemia, sodium and sometimes fluid restriction to support blood pressure management, and phosphorus restriction to reduce risk of bone disease and cardiovascular damage.
For many patients, however, these types of dietary restrictions are not appropriate until very late stages, and by then there is not much to do but try to prepare for a smooth transition to dialysis. This is challenging for many patients who do not want to start dialysis and wish that they could have done something earlier as well as for their providers who feel they have little else to offer patients outside of dialysis.1 A paradigm shift from the “prevent complications” standard of care to a preserving kidney function model shines the spotlight on nutrition care (early and late) as an essential part of more ideal care for those with CKD. Accumulating evidence shows that a low protein diet, individualized mineral recommendations, support of gut health, and ensuring adequate vitamin intake can help preserve kidney function and reduce risk of progression.
Beyond Diet Restrictions
A low protein diet under the supervision of a dietitian repeatedly has been shown to support kidney health.2,3,4 There are multiple ways a low protein diet:
- Increases GFR2 and slowed progression to end stage kidney disease3,4
- Improves hyperfiltration, reduced nitrogen waste and reduced renal workload2,5,6
- Reduces proteinuria (by 20%-50%)5
- Improves lipids (cholesterol and triglycerides)2,4
- Improves glucose and hemoglobin A1c2
- Improves quality of life4
- Reduces dietary acid load6
Merely recommending a basic protein restriction without consistent medical oversight may provide temporary improvements, but long term, this can reasonably result in patients developing protein and micronutrient malnutrition or still consuming a high renal acid load diet, which negates many of the low protein diet benefits. A dietary pattern that meets patients’ protein and other nutrient needs provides long-term success for kidney health.7
Individualized Mineral Needs
Recent evidence supports the individualization of potassium, sodium, and phosphorus needs in patients with CKD rather than the historic blanket restrictions.8 This is a significant beneficial shift because this allows for a more liberal diet with low sodium, potassium rich foods to better support heart health, blood pressure management, micronutrient intake, reduced dietary acid load, improve dietary quality of life and gut health.8,9
Gut Health and Kidney Disease
Although the gut and kidney connection is a new consideration, and therapeutic targets are still evolving, it offers a way that nutrition care can support kidney disease health. The gut is major source of uremic toxins, and these toxins generate many inflammatory factors that can contribute to worsening renal function as well as cardiovascular issues. A diet that includes more healthy fats, fruits and vegetables and is lower in protein all support a healthier gut microbiome that reduces inflammation and kidney workload.9,10 There are also many commonly used medications that wreak havoc on the gut, and further exacerbate inflammatory gut conditions and increase risk for nutrient deficiency. (Such as proton pump inhibitors that increase the risk and progression of kidney disease as well).11 There are often viable nutrition or diet alternatives to these medications which are more cost effective, address the root issue, and provide an improved quality of life for the patient. This illuminates again how seeking only to prevent complications misses the bigger picture of how a higher quality dietary pattern supports all aspects of the patient’s health.
Adequate Vitamin Intake
Although the research on ideal vitamin intake and requirements in patients with CKD is scant, the research we do have demonstrates that these patients frequently have low intake or low levels of various vitamins, and that there is an increased risk of disease progression for those who have low intake in vitamins.12 Additionally, adequate vitamin intake helps to better manage inflammation, hormone balance, healthy metabolism, immunity, and other chronic conditions the patient may be dealing with.12 It is important to note that the frequently referenced DRI’s (Dietary Reference Intakes) are not intended to provide intake guidance for those with chronic disease, or body mass index (BMI) values outside of the “normal” range.13 Dietitians can play an integral role in assessing intake, risks and signs of deficiency, and dietary adjustments or supplements to ensure that patients with CKD have adequate intake of micronutrients. More attention to this in clinical practice will no doubt yield better more viable research to better establish optimal vitamin recommendations.
Putting It All Together
Using nutrition management as a tool can seem daunting, but here are some keys to maximize nutrition care as a therapeutic option to not only prevent complications, but preserve kidney function:
- Consider that effective and successful dietary interventions require time. Nephrology providers can play an effective and important role in initiating and reinforcing nutrition therapy while dietitians work with the patient to assess appropriate type of nutrition therapy to implement, support behavior change, and monitor outcomes.
- Network with renal dietitians to find partners in whom you can feel confident entrusting your patients’ care or consider including a dietitian in your care team in your office. The National Kidney Foundation has a tool for finding renal dietitians.
- Integrate a screening tool in your intake process to identify patients who can benefit from nutrition care. Starting small with things like specific diagnosis (like hyperkalemia, constipation or glomerular filtration rate less than 60 mL/min/1.73 m2) can get you started.
- Encourage and refer your patients to see a renal dietitian. Data show that 80%-90% of patients never see a dietitian prior to starting dialysis,14 although at least 32% of CKD patients are interested in being referred to see a dietitian.15 As more nephrology providers recognize the value nutrition care can bring to their patients this number will likely increase.
Lindsey Zirker MS, RD, CSR is a renal dietitian and Director of Clinical Services for the Kidney Nutrition Institute in Titusville, Florida. She specializes in autoimmune kidney disease and advanced practice medical nutrition therapy for people with kidney disease.
- Wong SPY, McFarland LV, Liu C, Laundry RJ, Hebert PL, O’Hare AM. Care practices for patients with advanced kidney disease who forgo maintenance dialysis. JAMA Intern Med. 2019;179(3):305–313. doi:10.1001/jamainternmed.2018.6197
- Perna S, Faisal F, Spadaccini D, et al. Nutritional intervention effectiveness on slowing time to dialysis in elderly patients with chronic kidney disease-A retrospective cohort study. Geriatrics (Basel). 2022;7(4):83. doi:10.3390/geriatrics7040083.