According to Gram Research analysis, a probiotic called Lactiplantibacillus plantarum WJL reduced muscle-wasting stress signals by 26% in kidney disease patients on low-protein diets, helping them maintain body weight and muscle mass while still protecting their kidneys. In a 2026 randomized controlled trial, patients taking the probiotic experienced significantly better body composition preservation compared to diet alone, though larger studies are needed to confirm these findings before widespread clinical use.
Researchers studied how a special probiotic called Lactiplantibacillus plantarum WJL could help people with chronic kidney disease who eat low-protein diets. Low-protein diets are recommended for kidney disease patients, but doctors worry they might cause muscle loss. In this study, both mice and human patients who took the probiotic while eating a low-protein diet maintained better muscle and body weight, while still getting the kidney benefits of the diet. The probiotic worked by reducing stress signals in the body that normally cause muscle breakdown. This suggests a new way to make low-protein diets safer and more effective for kidney disease patients.
Key Statistics
A 2026 randomized controlled trial found that Lactiplantibacillus plantarum WJL reduced the stress hormone FGF21 by 26% in chronic kidney disease patients on low-protein diets, helping preserve muscle mass and body weight.
In mouse models of chronic kidney disease, the probiotic Lactiplantibacillus plantarum WJL increased weight gain by 247% compared to low-protein diet alone, while maintaining kidney-protective benefits.
According to research reviewed by Gram, low-protein diets alone increased the stress hormone FGF21 by 2.9-fold in human kidney disease patients and 28-fold in mice, but adding the probiotic suppressed this muscle-wasting signal.
A 2026 study found that Lactiplantibacillus plantarum WJL restored circulating amino acid levels in kidney disease patients while reducing harmful uremic toxins, supporting both muscle maintenance and kidney protection.
The Quick Take
- What they studied: Whether adding a specific probiotic supplement to a low-protein diet could help people with chronic kidney disease maintain muscle while still protecting their kidneys.
- Who participated: The study included both laboratory mice with kidney disease and a group of human patients with chronic kidney disease who don’t have diabetes. The exact number of human participants wasn’t specified in the abstract.
- Key finding: Patients and mice taking the probiotic supplement while on a low-protein diet kept more muscle and body weight (-26% reduction in a stress hormone called FGF21) compared to those on the diet alone, while still getting kidney protection benefits.
- What it means for you: If you have chronic kidney disease and your doctor recommends a low-protein diet, a probiotic supplement might help you avoid losing muscle mass. However, more research is needed before doctors can widely recommend this approach. Talk to your healthcare provider before starting any new supplement.
The Research Details
This research combined two approaches to understand how a probiotic could help kidney disease patients. First, researchers studied mice with kidney disease, giving some a low-protein diet alone and others a low-protein diet plus the probiotic supplement. They measured changes in muscle, body weight, kidney function, and stress hormones. Then, they conducted a randomized controlled trial with human patients with chronic kidney disease, randomly assigning them to receive either the probiotic or a placebo while following a low-protein diet. Researchers tracked the same measurements in both groups over time.
The study focused on understanding how the probiotic works at a biological level. They measured gut bacteria composition, stress hormones (particularly one called FGF21), amino acid levels, and toxic compounds that build up in kidney disease. This detailed approach helped explain not just whether the probiotic helped, but how it helped.
Both the mouse experiments and human trial used the same probiotic strain (Lactiplantibacillus plantarum WJL) to ensure consistency. The researchers were particularly interested in whether the probiotic could prevent the muscle-wasting side effect that sometimes occurs with low-protein diets.
Low-protein diets are standard treatment for kidney disease because they reduce the workload on damaged kidneys. However, doctors have long worried that these diets might cause patients to lose muscle mass and become malnourished. Understanding how a probiotic can prevent this problem is important because it could make low-protein diets safer and more acceptable to patients. By studying both animals and humans, and by measuring the biological mechanisms involved, this research provides stronger evidence than studies that only look at one or the other.
This study has several strengths: it combined animal research with human trials, which provides more convincing evidence; it measured multiple health markers rather than just one outcome; and it investigated the biological mechanism explaining how the probiotic works. However, the study has limitations: the human trial sample size appears small (exact number not specified), and the researchers note that larger clinical trials are needed to confirm the findings. The study was published in a peer-reviewed journal, meaning other experts reviewed the methods and results before publication.
What the Results Show
In both mice and human patients, the low-protein diet improved how the body handled blood sugar and reduced toxic compounds that build up in kidney disease. However, the diet alone caused the body to produce high levels of a stress hormone called FGF21, which signals the body to break down muscle for energy.
When researchers added the probiotic supplement (Lactiplantibacillus plantarum WJL) to the low-protein diet, something important happened: the stress hormone FGF21 decreased by 26% in humans and was significantly suppressed in mice. More importantly, patients and mice taking the probiotic maintained much better body weight and muscle mass. In mice, weight gain was 247% higher in the probiotic group compared to diet-only controls. In human patients, body mass index decreased by only about 0.5 kg/m² (a much smaller loss than expected).
The probiotic also restored amino acid levels in the blood, which are the building blocks needed to maintain muscle. The researchers found that the probiotic worked by changing the composition of gut bacteria and reducing stress signals that normally cause muscle breakdown. Importantly, all the kidney-protective benefits of the low-protein diet were preserved—the probiotic didn’t interfere with the diet’s main purpose.
The study revealed that the probiotic changed which genes were active in gut bacteria, specifically reducing pathways involved in making certain amino acids. This suggests the probiotic helps the body use amino acids more efficiently. The researchers also found that FGF21 levels correlated with body composition—higher FGF21 was associated with more fat and less muscle, confirming that this stress hormone plays a key role in muscle loss. Additionally, the probiotic reduced circulating levels of uremic toxins (harmful compounds that build up in kidney disease), which may provide additional kidney protection.
This research builds on previous studies showing that low-protein diets help slow kidney disease progression, but addresses a major concern doctors have had: whether these diets cause dangerous muscle loss. Previous research had identified FGF21 as a stress hormone involved in amino acid deficiency, but this is one of the first studies to show that a probiotic can suppress FGF21 and prevent muscle wasting in kidney disease patients. The findings align with earlier research showing that specific probiotics can improve nutritional status in kidney disease, but provide new mechanistic understanding of how this works.
The study has several important limitations. The exact number of human participants in the clinical trial was not specified in the abstract, making it difficult to assess statistical power. The study duration is not mentioned, so it’s unclear how long patients were followed. The research focused on nondiabetic kidney disease patients, so results may not apply to people with diabetic kidney disease, which is a common form. The researchers themselves note that larger clinical trials are needed to confirm these findings before the probiotic can be widely recommended. Additionally, the study doesn’t address cost, availability, or potential side effects of long-term probiotic use.
The Bottom Line
Based on this research, a probiotic supplement (Lactiplantibacillus plantarum WJL) appears promising for helping kidney disease patients maintain muscle while on a low-protein diet. However, confidence in this recommendation is moderate because the human trial was small and needs to be repeated in larger groups. Current recommendation: If you have chronic kidney disease and are on a low-protein diet, discuss with your nephrologist (kidney specialist) whether this probiotic might be appropriate for you. Do not start any supplement without medical approval, as probiotics can interact with medications or cause problems in some patients.
This research is most relevant to people with chronic kidney disease (stages 3-5) who have been prescribed a low-protein diet by their doctor. It’s particularly important for patients concerned about muscle loss or those who have experienced weight loss on a low-protein diet. The study focused on nondiabetic kidney disease, so people with diabetic kidney disease should discuss applicability with their doctor. People with weakened immune systems, those taking immunosuppressive medications, or those with certain infections should consult their doctor before taking probiotics. This research is less relevant to people with healthy kidneys or those not on a low-protein diet.
In the mouse studies, benefits appeared within the study period (timeline not specified), and in human patients, improvements in body weight and stress hormones were measurable. However, the study doesn’t specify how long patients need to take the probiotic to see benefits or how long benefits persist after stopping. Realistic expectations: If your doctor recommends this probiotic, you should expect to see changes in body weight and muscle maintenance over weeks to months, similar to other dietary interventions. Long-term benefits and safety require further study.
Frequently Asked Questions
Can probiotics help prevent muscle loss in kidney disease patients on low-protein diets?
Research shows that Lactiplantibacillus plantarum WJL may help preserve muscle mass in kidney disease patients on low-protein diets by reducing stress signals that cause muscle breakdown. A 2026 trial found the probiotic reduced the muscle-wasting hormone FGF21 by 26% while maintaining kidney benefits. However, larger studies are needed before doctors can widely recommend this approach.
How does the probiotic Lactiplantibacillus plantarum WJL work for kidney disease?
The probiotic works by changing gut bacteria composition and suppressing FGF21, a stress hormone that signals the body to break down muscle when amino acids are low. It also restores amino acid levels and reduces toxic compounds that build up in kidney disease, providing dual benefits for kidney and muscle health.
Is a low-protein diet safe for chronic kidney disease if I take this probiotic?
According to research reviewed by Gram, combining a low-protein diet with Lactiplantibacillus plantarum WJL appears safer than diet alone because the probiotic helps prevent muscle loss while preserving kidney-protective benefits. However, you must work with your nephrologist to ensure the combination is appropriate for your specific condition and medications.
What are the side effects of Lactiplantibacillus plantarum WJL for kidney disease patients?
The study abstract doesn’t detail side effects, but probiotics generally cause mild digestive changes in some people. Kidney disease patients should consult their doctor before starting probiotics, as they may interact with medications or cause problems in people with weakened immune systems.
How long does it take to see benefits from this probiotic supplement?
The study doesn’t specify the timeline for benefits, but changes in body weight and stress hormones were measurable during the trial period. Realistic expectations are weeks to months, similar to other dietary interventions. Consult your doctor about realistic timelines for your individual situation.
Want to Apply This Research?
- Track weekly body weight and monthly body composition measurements (if available through your healthcare provider). Also monitor energy levels and muscle strength using simple tests like how many stairs you can climb without fatigue or how long you can stand from a seated position without using your hands.
- If your doctor approves this probiotic, set a daily reminder to take it at the same time each day (consistency improves effectiveness). Pair it with your low-protein diet tracking to monitor whether you’re maintaining muscle while following dietary restrictions. Log any side effects or changes in digestion.
- Create a monthly check-in to review body weight trends, energy levels, and any digestive changes. Share this data with your nephrologist at regular appointments. If using a health app, track protein intake against recommendations, probiotic adherence, and body weight together to see correlations. Set alerts for quarterly kidney function tests (as recommended by your doctor) to ensure the combination of diet and probiotic is working.
This article summarizes research findings and is not medical advice. Chronic kidney disease is a serious condition requiring ongoing medical supervision. Do not start, stop, or change any diet, supplement, or medication without consulting your nephrologist or healthcare provider. Probiotics may not be appropriate for all patients, particularly those with weakened immune systems, certain infections, or those taking specific medications. The probiotic discussed (Lactiplantibacillus plantarum WJL) is not yet widely available or approved for clinical use in kidney disease management. Always discuss any new supplement with your healthcare team before use. This research is preliminary and larger clinical trials are needed before widespread clinical recommendations can be made.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.