Are Low-Protein Diets Beneficial for CKD Patients?

When it comes to chronic kidney disease (CKD), providers don’t necessarily need to cast aside diet management in favor of newer treatments. Combining dietary interventions with drug management and dialysis can prolong life, maintain electrolyte balance, reduce medical costs, and slow disease progression in CKD patients.

Low-protein diets were the mainstay of CKD management before the advent of dialysis because they rest the kidneys and reverse uremia toxicity.

Resting the kidney appears paradoxical early on because the glomerular filtration rate (GFR) decreases. However, doing so is necessary to prevent CKD-related sequelae. GFR is only a surrogate marker of kidney function, and renally-mediated electrolyte balance and vitamin D activation are also crucial to patient health. Pharmacists can assist in these efforts by monitoring patients’ medications for drug-lab interactions and recommend targeted vitamin and mineral supplements.

Previous studies examining low protein diets for CKD patients produced inconclusive results. The patient cohorts exhibited low adherence, and diet alone is rarely comparable to dialysis in efficacy. Medical ethics conflict with randomization into dialysis (control group) and an unproven intervention in acutely ill patients.

However, provider concerns about malnutrition in CKD patients appeared unfounded. Even patients randomized to very-low-protein diets were receiving adequate nutrients in previous trials, though unsupervised low-protein diets are often low in iron and vitamins B12 and D.

Advanced CKD patients are already deficient in activated vitamin D, so there’s greater concern earlier in the disease course. The addition of appropriate vitamin and mineral supplements can reduce patient and provider concerns.

In recent years, the daily protein intake recommendation has dropped to a “moderate” level (0.8 g/kg). This has reduced the stigma of low-protein diets that tend to limit or eschew meats in favor of a diet similar to the Mediterranean diet. Originally, traditional diets were low-protein worldwide by necessity. Twentieth-century improvements in refrigeration and transport allowed for affordable mass consumption of protein-rich meat products.

Since unrestricted vegans tend to consume 0.7 to 0.9 g/kg of protein daily, vegan CKD patients require small changes to adopt a low-protein diet (~0.6 g/kg). One study of Buddhist monks found that their naturally very-low-protein vegan diet slowed CKD progression considerably.

Protein-free medical foods are a prescription option allowing patients to continue their dietary habits. However, medical foods are often too expensive for uninsured or underinsured patients.

Italian scientists developed calorie-rich protein-free medical foods in response to dialysis’ prohibitive cost and limited availability in their country. Patients were unwilling to consume natural foods low in protein, like tapioca, butter, sugar, fruits, and vegetables, due to perceived monotony and poor or bland taste.

Very-low-protein diets (0.3 g/kg/day) with amino acid supplements are an effective option for patients trying to defer dialysis initiation. However, this restrictive diet needs close prescriber oversight, and pill burden complicates adherence. Malnutrition is most likely to be seen with this type of diet because of the limited scope and quantity of food intake. Provider-nutritionist-pharmacist cooperation is crucial to the welfare of patients using this method.

Patients may use medical supervision for lifestyle interventions adjunctively or in place of certain conventional interventions. The optimal diet is flexible, ensures patient satisfaction, reflects patient choice, encourages high adherence, and takes into account patients’ comorbidities. Pharmacists are central to the provision of medical food and are valuable resources regarding vitamin and mineral supplementation.

References

Piccoli GB, et al. Low protein diets in patients with chronic kidney disease: a bridge between mainstream and complementary-alternative medicines? BMC Nephrology. 2016;17:76.