Can Dogs Have Kefir? Why It Isn’t the Best Probiotic & What to Use Instead
Is kefir a good probiotic for dogs? See what peer-reviewed studies show, why kefir isn’t efficient as a probiotic, and better, evidence-based options.
As a canine nutritionist, I’m all for simple, real-world strategies that support gut health. Kefir pops up a lot in owner conversations—it’s trendy, inexpensive, and easy to pour over dinner. But does kefir work as a probiotic for dogs?
Short answer: kefir is a fermented food, not a reliable, clinically proven probiotic therapy for dogs. The research in canines is limited and inconsistent; product quality is highly variable; and the live microbes in kefir aren’t the same as the specific, strain-verified probiotics that show benefits in controlled trials.
Below, I’ll unpack what kefir is, what the veterinary literature actually says, why it’s often inefficient as a probiotic for dogs, and what better options look like if you want evidence-based gut support.
Fermented foods vs. probiotics
Fermented foods (like kefir, yoghurt, kimchi) are foods made through microbial fermentation. They may contain live microbes—but they aren’t automatically probiotics.
A probiotic is “a live microorganism that, when administered in adequate amounts, confers a health benefit on the host.”
That difference matters: probiotics are strain-specific, dose-specific, and must demonstrate a health benefit in the target host. Everyday kefir products rarely meet that definition—especially in dogs.
What does the dog research on kefir say?
1) Kefir shows minor microbiome effects in healthy dogs
A 2023 controlled trial compared milk (control) with commercial kefir and traditional, home-brewed kefir in healthy adult dogs. Despite large differences in microbial counts between the two kefirs, effects on faecal microbiota and metabolites were minor, with no impact on macronutrient digestibility or faecal IgA.
2) A single-strain “kefir species” didn’t do much either
A 2020 study supplementing Lactobacillus kefiri in healthy dogs found no meaningful changes in faecal IgA and only limited shifts in microbial composition.
3) One small 2024 study suggests modest digestibility changes
A 2024 paper (21 dogs) reported improved protein digestibility and lower serum cholesterol/triglycerides with kefir added to a dry diet. Useful, but note: these were biomarker changes in healthy dogs, not clinical outcomes.
4) Many canine kefir products don’t match labels
A 2020 assessment of commercial kefir products marketed to pets found mismatches between what was on the label and what was inside (microbial content, densities, and contaminants), highlighting a quality control problem that makes consistent dosing unlikely.
Bottom line: across controlled canine studies, kefir shows small or inconsistent effects in healthy dogs and lacks robust evidence for treating specific conditions.
Why kefir isn’t an efficient probiotic for dogs (8 key reasons)
It isn’t strain-verified. Probiotic effects are strain-specific; kefir microbes aren’t the same as strains tested in dogs.
Counts are variable. Fermentation, milk type, and storage change microbe density.
Dog trials show minor outcomes. No consistent improvements in microbiota or immune markers for healthy dogs
Canine relevance is uncertain. Microbes may not colonise or interact beneficially with the dog gut.
Dose and shelf-life are murky. Few kefir products confirm viable CFUs through shelf-life.
Histamine & biogenic amines. Fermented dairy can contain tyramine/histamine, problematic for sensitive dogs.
Fat and lactose matter. Kefir is lower in lactose but not free of it, and some types are too fatty for GI-sensitive dogs.
Food ≠ therapy. Kefir is a topper, not a targeted probiotic therapy.
Better options: probiotics with evidence in dogs
Several strain-identified probiotics have published benefits in dogs:
Enterococcus faecium SF68 (NCIMB 10415): shown to reduce diarrhoea in shelter dogs; mixed results in chronic enteropathy.
Saccharomyces boulardii: improved clinical scores in dogs with chronic enteropathies in a double-blind trial.
Bifidobacterium animalis subsp. lactis AHC7: evidence for reducing stress-associated diarrhoea and improving stool quality.
Synbiotics (probiotic + prebiotic): large shelter study showed reduced diarrhoea incidence compared to placebo.
Reality check: pooled analyses show small benefits overall—dietary management remains the most powerful tool, especially in chronic cases.
Where diet fits
A significant proportion of chronic enteropathy cases in dogs are food-responsive. In one pilot trial, dogs improved with diet alone, and adding a probiotic provided no additional benefit. This highlights why diet-first strategies are the cornerstone of management, we need to assess a dog’s diet FIRST before adding anything else in,
Kefir as a topper: safe use
If you want to use kefir:
Choose plain, unsweetened, low-fat kefir (no flavours, sugar, or xylitol).
Feed small portions (about 1 tsp per 5 kg bodyweight).
Avoid in dogs with pancreatitis, dairy allergies, or histamine intolerance.
Home brewing is inconsistent—microbe content is unstandardised and contamination is possible.
Prebiotics & postbiotics
Prebiotics (like FOS, MOS, inulin) support healthy gut bacteria and are more predictable than kefir. Whole food prebiotics include chicory root, pumpkin, sweet potato and other forms of fibre.
Postbiotics (inactivated microbes with beneficial compounds) are stable, safe, and increasingly studied in dogs.
Final thoughts
Kefir is a fermented food, not a proven probiotic therapy for dogs.
Controlled studies show limited benefits in dogs.
For gut health support, choose strain-verified probiotics or consider postbiotics, always alongside the right diet.
Kefir can still be used as a nutritious topper in healthy, dairy-tolerant dogs—but not as a therapeutic tool.
References
ISAPP Consensus on fermented foods vs probiotics.
ISAPP probiotic definition and criteria.
Mora-Ortiz, M. et al. (2023). Effects of kefir supplementation in healthy dogs: minor microbiome outcomes.
Bresciani, F. et al. (2020). Lactobacillus kefiri supplementation in dogs: limited faecal IgA and microbiome effects.
Chiofalo, B. et al. (2024). Kefir improves protein digestibility and lipid metabolism in healthy dogs.
Commercial kefir quality analysis in pet products (2020). Mismatch between labels and microbial content.
Schmitz, S. et al. (2015). Randomised trial: Enterococcus faecium in chronic enteropathy.
Pascher, M. et al. (2008). E. faecium reduces diarrhoea incidence in shelter dogs.
Rossi, G. et al. (2014). Saccharomyces boulardii in chronic enteropathy: double-blind placebo-controlled trial.
Kelley, R. et al. (2009). Bifidobacterium animalis subsp. lactis AHC7 in stress diarrhoea.
Gagné, J. W. et al. (2021). Synbiotics in shelter dogs: reduced diarrhoea incidence.
Ritchie, M. et al. (2022). Biogenic amines in fermented dairy: variability and risks for sensitive dogs.
Schmitz & Suchodolski (2019). Probiotics in canine GI disease: systematic review and meta-analysis.
Salminen, S. et al. (2021). Postbiotics: definition, scope and applications.
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