Water kefir and microbiome diversity:
why 50 strains do more than 5, and what makes fermented probiotics different
An animal that never really recovers after antibiotics. Varying stools that do not improve with standard probiotics. A microbiome that has lost its diversity after years of medication. Water kefir works differently than regular probiotics. This is the scientific explanation.
By Stefan Veenstra DVM
The problem with regular probiotics
Most probiotic supplements on the market contain one to five strains of bacteria, often Lactobacillus acidophilus and Bifidobacterium longum. These are useful strains, but they represent a fraction of the ecosystem that forms a healthy gut microbiome. A healthy gut microbiome in dogs and cats contains hundreds of different species of bacteria, fungi, and yeast that work together in a complex web of interdependencies.
After antibiotics, deworming or chronic illness, that ecosystem is disrupted. The pathogenic and opportunistic species are the first to grow back because they have less competition. Adding five strains does not solve that problem. You need diversity, not just quantity. And diversity is exactly what water kefir offers.
What is water kefir and why is it different?
Water kefir is a fermented drink that is created by fermenting water, sugar, and kefir grains together. These kefir grains are not grains in the biological sense but a symbiotic community of bacteria and yeasts that are locked in a polysaccharide matrix. During fermentation, these microorganisms multiply and produce lactic acid, acetic acid, carbonic acid and other bioactive substances.
The result is a product with more than 50 different bacterial and yeast strains that are present in their natural relationship to each other. This mutual relationship is not arbitrary: the strains have balanced themselves during fermentation and reinforce each other’s effect. That is fundamentally different from putting five isolated strains together in a capsule.
NGD Care Fermented Probiotics is this water kefir complex freeze-dried in capsules. Freeze-drying preserves the living microorganisms and their bioactive compounds without the heat that would kill them. The result is a stable, easy-to-dose supplement that delivers the completeness of fermented water kefir in a practical form for daily use in dogs, cats and humans.
The tribes: what does who do?
Fermented Probiotics contains three functional groups of microorganisms, each of which plays its own role in the gut microbiome:
The backbone of the lactic acid bacteria complex. Produce lactic acid that lowers gut pH and inhibits pathogenic overgrowth. Stimulate mucosal IgA production for local immunity. Strengthen tight junctions through SCFA manufacturing. L.Brevis, acidophilus, casei, kefir and kefiranofaciens each have a specific spectrum of action.
The yeasts in water kefir are not the pathogenic Candida albicans but commensal species that are essential for the balance in the gut microbiome. Saccharomyces cerevisiae and S. pastorianus support the intestinal barrier, produce B vitamins and inhibit the overgrowth of pathogenic fungi via competitive exclusion.
Produce acetic acid (Acetobacter) and exopolysaccharides (Leuconostoc mesenteroides). Acetic acid has antimicrobial activity and inhibits Clostridium species. Leuconostoc mesenteroides stimulates the production of butyrate via cross-feeding of butyrate-producing Firmicutes: an indirect but essential contribution to intestinal barrier repair.
Review · Frontiers in Microbiology 2025 · Kefir and microbiome diversity
Kefir consumption led to significant increases in Blautia wexlerae and B. luti (butyrate and propionate producers), Bifidobacterium breve and Leuconostoc mesenteroides. These bacteria are associated with SCFA production that supports the mucus layer and gut barrier integrity. Fermented foods with high microbiome diversity promoted more consistent microbiome recovery than products with limited strain spectrum.
The role of inulin: prebiotic as a foundation
In addition to the fermented water kefir complex, Fermented Probiotics also contains chicory inulin as a prebiotic. Inulin is a fermentable fiber that is not digested by the body’s own digestive system but reaches the large intestine intact, where gut bacteria ferment it into short-chain fatty acids.
This is essential for two reasons. First, inulin increases the survival rate of the added probiotic strains: they have food readily available as soon as they arrive in the gut. Second, inulin stimulates the growth of already present commensal bacteria, especially Bifidobacterium and Lactobacillus species, extending the prebiotic effect beyond just the capsule contents. Probiotic plus prebiotic together is called a synbiotic: a combination that is demonstrably more effective than either individually.
When is Fermented Probiotics most relevant?
After antibiotics or deworming
Antibiotics not only destroy pathogenic bacteria but also a large part of the commensal microbiome. Deworming, flea medicines and other medications structurally disrupt the microbiome balance. Start immediately after a course and continue for at least 4-8 weeks for sustainable recovery.
Chronic intestinal complaints
Fluctuating stools, recurrent diarrhea, bloated abdomen or poor food intake that do not improve with single probiotics. The broad stem composition of water kefir appeals to a larger spectrum of the disturbed microbiome.
Phase 2 of the Intestinal Protocol
After the biofilm phase (Biofilm Balance) and the first remediation, the microbiome is built up. Fermented Probiotics delivers the diversity that phase 2 requires: not just one or two strains but a fully diverse ecosystem that aligns with the normal gut microbiome.
Basic daily support
For animals that receive structural medication, are sensitive to intestinal complaints or live in environments with high microbiome pressure. As a long-term microbiome maintenance in addition to Prebiotic Fibers and the gut protocol.
Veterinary study · PMC 2020 · Kefir products for dogs and cats
A study of commercial kefir products for companion animals showed significant variation in microbial composition and viability between products. The study emphasized the importance of standardized production and specifying microbial composition for therapeutic use in dogs and cats. Products with higher strain diversity and guaranteed live count showed better colonization results.
Synergy with other NGD Care supplements
Fermented Probiotics work best as part of a broader microbiome recovery plan. The combination I use the most:
Fermented Probiotics + Prebiotic Fibers
The probiotics and the prebiotics together: the strains of water kefir are fed several prebiotic fibers. Doubles the effect of both supplements.
Fermented Probiotics + Biofilm Balance + Prebiotic Fibers
The core of the Gut Protocol: first break through biofilm (Biofilm Balance), then build up (Fermented Probiotics + Prebiotic Fibers). Phased deployment for maximum effectiveness.
Water kefir and histamine: when is caution advised?
This is a topic that comes up regularly in practice and deserves an honest answer. Water kefir is a fermented product. Fermentation produces histamine, and some strains of bacteria in kefir are histamine-producing. This means that water kefir can worsen symptoms in animals with histamine intolerance, in particular itching, skin reactions and gastrointestinal complaints.
The histamine-producing strains in the NGD Care Fermented Probiotics formula are notably Lactobacillus casei, L. helveticus and Enterococcus durans. In animals with an active histamine intolerance or suspicion of mast cell activation, starting with water kefir can cause temporary symptoms or worsen existing itching symptoms.
Review · PMC 2024 · Water kefir: possibilities and limitations
Water kefir has potential health benefits but also has limitations in consumption. The microbial composition and histamine content vary depending on the fermentation duration, the substrates used, and the specific kefir grains. With shorter fermentation, the histamine content is usually lower.
But: it is more nuanced than just avoidance
The reasoning that kefir should always be avoided in case of itching is too simple. Two opposing mechanisms are active at the same time. On the one hand, some strains produce histamine. On the other hand, kefir and other fermented products also contain strains that stimulate diamine oxidase (DAO), the enzyme that breaks down histamine in the gut. Low levels of DAO-producing bacteria such as Lactobacillus rhamnosus, Bifidobacterium infantis, Bifidobacterium longum and Lactobacillus plantarum are a known cause of histamine intolerance. A disrupted microbiome without those strains processes histamine worse than a diverse microbiome with those strains.
This means that the question is not only how much histamine water kefir contains, but also what it does to the microbiome in the longer term. A microbiome that is more varied and richer in DAO-producing bacteria can actually deal better with histamine in the long run. Studies on rice-based kefir showed promising results in inhibiting histamine release in the gut, with kefir at lower doses not increasing serum histamine. The net outcome therefore depends on the starting point of the microbiome, the dose and the individual sensitivity.
Practical advice for animals with itching or histamine sensitivity
- Start with a quarter of the recommended dose and slowly build up over 2-4 weeks
- Actively observe for worsening of itching, skin reactions, or gastrointestinal discomfort for the first two weeks
- Significantly worsens itching in the first week: stop temporarily and start again after lowering the histamine load via food
- If the symptoms do not disappear at low doses: consider a DAO-supporting alternative without histamine-producing strains as a temporary bridge
- When in doubt: discuss it with Stefan Veenstra DVM via Natuurlijk Gezonde Dieren for an individually tailored protocol
The unique value of water kefir, its wide strain diversity including yeasts and its synergistic fermentation matrix, cannot be replicated with a single DAO-supporting probiotic. In animals with mild histamine sensitivity, a slow build-up is the best approach in most cases. In animals with severe mast cell activation or demonstrable histamine intolerance, a targeted alternative probiotic is temporarily more sensible, only to make the switch to water kefir later, when the intestinal barrier has been restored.
Conclusion
Fermented Probiotics is no ordinary probiotic. It is a fully fermented water kefir complex with more than 50 strains of bacteria and yeast in their natural symbiosis, supplemented with chicory inulin as a prebiotic. That combination offers what isolated probiotics cannot: true microbiome diversity that supports the gut microbiome on multiple levels at once.
For dogs and cats recovering from medication, suffering from recurring intestinal complaints or as part of the Gut Protocol, Fermented Probiotics is the most broad and complete probiotic support we offer.
Literature
- Moretti AF, et al. Water kefir, a fermented beverage containing probiotic microorganisms: from ancient and artisanal manufacture to industrialized and regulated commercialization. Future Foods. 2022;5:100123.
- Frontiers in Microbiology. Evaluation of kefir consumption on gut microbial diversity in a healthy young population using full-length 16S rRNA sequencing. 2025;16:1587831.
- AIMS Microbiology. Antioxidant and anti-inflammatory properties of water kefir microbiota and its bioactive metabolites. 2024; 10(4):756-811.
- Frontiers in Food Science and Technology. Kefir as a functional probiotic: microbial composition and health effects. 2025;4:1725280.
- PMC. Assessment of commercial companion animal kefir products for label accuracy of microbial composition and quantity. 2020.
- Bozkir E, et al. Challenges in water kefir production and limitations in human consumption: a comprehensive review. Heliyon. 2024; 10:e33501. PMC11259891.
- Frontiers in Nutrition. Histamine intolerance and the gut microbiome: the role of DAO-producing bacteria including Lactobacillus rhamnosus, Bifidobacterium infantis and Lactobacillus plantarum. 2022; doi:10.3389/fnut.2022.1018463.
- Fix Your Gut. Histamine-producing strains in kefir: Lactobacillus bulgaricus, L. casei, L. helveticus. Overview article 2025.
This information is educational in nature and based on available scientific literature. Fermented Probiotics is intended as a dietary supplement for support and does not replace veterinary consultation. In case of severe or persistent complaints, always consult a veterinarian.