Are low protein diet in CKD still recommended for those with malnutrition?

I have been talking about protein (low protein and very low protein diets) in my last two blog posts. This prompted me to ask myself, but are low protein diets for everyone with CKD? What if our patients have malnutrition? What should we recommend then?

What evidence is there?

Not too long, I co-authored a review about sarcopenia and sarcopenic obesity in CKD. For this paper, my co-authors and I reviewed 66 papers. Our goal was to synthesize the evidence on what we should do for adults with kidney disease with sarcopenia. Not all my patients with poor nutritional status have sarcopenia. But there is definitely some overlap.

I also recently spent some time reading the April 2023 article published in Clinical Nutrition by Piccoli et al, Nutritional status and the risk of malnutrition in older adults with chronic kidney disease–implications for low protein intake and nutritional care A critical review endorsed by ERN-ERA and ESPEN. In this article, the authors focused on protein recommendations in older adults and had provided some excellent food for thought.

What should we do?

If we are worried about malnutrition or sarcopenia – remember adequate energy is key. Step 1 is ensuring our patients are getting enough energy.

If our patient’s aren’t getting enough energy, ingested protein will be catabolized and doesn’t support muscle mass anyways. So start there. My recommendation is to aim for at least 30-35kcal/kg and adjust as necessary.

Second step is figure out the protein by considering which concern is most pressing. If the main cause of reduced intake is related to uremic symptoms, protein restriction may be indicated. Reducing protein intake can help reduce urea levels and help slow kidney function decline. This might actually help our patient’s feel better and improve their intakes.

If malnutrition is not related to uremia and if kidney function is stable, liberalized protein is likely more appropriate. Piccoli et al discuss that for older adults protein intakes of 1.0-1.2g/kg per day can help with muscle mass preservation. However, experts caution against protein intakes above 1.3g/kg due to concerns with excess burden on the kidneys.

Take Aways

Are low protein diets for everyone? Nope. Are low protein diets for some? Yes.