Probiotics Disputed Role in CKD Management

Chronic kidney disease (CKD) is a leading health concern in older cats, and while diet and hydration remain central to management, researchers are exploring adjunctive therapies that support overall health. One area of interest is the gut — specifically, whether probiotics (beneficial live microbes) might influence the gut-kidney axis in a way that helps cats with CKD¹.

The Gut-Kidney Connection

The gut and kidneys communicate through a complex network of metabolites and immune signals. When kidney function declines, gut dysbiosis (imbalance in gut microbes) can occur. This imbalance may lead to increased production or absorption of gut-derived uremic toxins, which the kidneys normally filter out. Elevated levels of toxins such as indoxyl sulfate and p-cresyl sulfate have been linked to worsening kidney function and systemic inflammation.

Because of this connection, scientists have wondered whether changing the gut microbiome — for example, with probiotics — could help reduce toxin production and ease the burden on the kidneys.

What Research Shows So Far

Studies are still emerging, but there are intriguing findings:

• A recent pilot study in cats with stage 2–3 CKD found that daily administration of a probiotic mixture with Lactobacillus strains over eight weeks was associated with maintained or reduced creatinine levels and improvements in quality-of-life indicators. These changes were linked to modifications in gut microbiota composition and reduced levels of harmful metabolites¹.
• Some research in dogs with CKD has shown improvements in gut health and fecal consistency when probiotics were used alongside a renal diet, suggesting benefits for digestive comfort and overall well-being².
• In humans and animal models, probiotics have been shown to help lower concentrations of some uremic toxins by altering gut bacterial metabolism — although effects on core kidney function markers like creatinine and urea in controlled trials remain mixed³.

What This Means for Cat Owners

Currently, evidence suggests that probiotics may offer supportive benefits — particularly by promoting a healthier gut environment and potentially reducing harmful gut-derived toxins — but they are not a standalone treatment for CKD. Some cats may respond better than others, and benefits can vary based on the specific probiotic strains used and administration method⁴.

Veterinarians sometimes recommend probiotics as part of a holistic CKD management plan that includes:

• Therapeutic renal diets

• Adequate hydration

• Phosphorus and protein control

• Monitoring of clinical status and laboratory values

Probiotics may be most effective when chosen carefully (based on safety and strain characteristics) and when used in conjunction with other veterinarian-directed therapies⁵.

A Word of Caution

Not all probiotics are created equal, and not all strains have shown benefits in CKD. Some commercial products marketed for renal health lack robust clinical evidence. Always consult your veterinarian before adding a probiotic to your cat’s regimen, especially if the cat has concurrent digestive issues or is on multiple treatments.

¹Investigating the Efficacy of Kidney-Protective Lactobacillus Mixture-Containing Pet Treats in Feline Chronic Kidney Disease and Its Possible Mechanism
²Effect of a feed supplement containing probiotics on fecal score and clinical parameters in dogs with chronic kidney disease and intestinal disorders: A pilot study
³Efficacy of Probiotics Supplementation On Chronic Kidney Disease: a Systematic Review and Meta-Analysis
⁴Insights into the gut-kidney axis and implications for chronic kidney disease management in cats and dogs
⁵Application of Probiotics in Cats and Dogs: Benefits and Mechanisms