Probiotics are one of the fastest growing dog supplements.
That’s because few other supplements can have such a large impact on the immune system and health. As we learn more about gut bacteria and the large role they play in health and metabolism, we work harder to keep our dogs’ microbiome healthy and balanced.
But can probiotics play a role in building a healthy gut?
What Is The Microbiome?
Bacteria live in all parts of your dog’s digestive tract. There are just a few that live in the stomach but as you travel down the intestines, the numbers of bacteria increase. But, by far, most bacteria live in your dog’s colon.
The complex community of bacteria and other microorganisms in your dog’s gut is called the microbiome. These bacteria all function together and they work just like any other organ. In fact, scientists call the microbiome “the forgotten organ.”
Each microbiome is unique to each dog, just like a fingerprint. That’s because every dog is exposed to a unique environment and diet.
RELATED: Probiotics: When they help and when they harm …
What Are Probiotics?
Probiotics are live organisms that provide health benefits. These good bacteria are found in your dog’s gut, in fermented foods and in supplements. Certain yeast species are also considered probiotic.
Beneficial bacteria have a few key jobs in your dog’s body. They help:
- Digest food
- Produce key vitamins (including vitamin K and B vitamins)
- Produce serotonin and influence mood
- Produce enzymes
- Reduce the gut pH
- Crowd out harmful bacteria
- Produce fatty acids that discourage the growth of harmful bacteria
- Support the immune system
What Are Prebiotics?
Bacteria eat exactly what your dog eats. But beneficial bacteria love one food in particular … fiber. There are two important sources of fiber for your dog’s gut bacteria.
Soluble fiber is called soluble because it forms a hydrated mass with water. Soluble fiber is almost completely fermented in the colon by the bacteria living there. It’s one of their main sources of food. Examples of soluble fiber include:
- Pectin from fruit
- Beta-glucan from mushrooms
- Seaweed and chlorella
- Some grains
- Guar gum (extracted from guar beans
- Methylcellulose (a chemical compound extracted from cellulose).
This starch is resistant to digestive enzymes in the small intestine, so it also passes to the colon mostly unchanged.
Collectively, we call these substances prebiotics. Once these prebiotics reach your dog’s colon, the trillions of bacteria that live there eat them up (they ferment them).
How Probiotics Support The Immune System
When bacteria eat fiber, they “poop out” short chain fatty acids (SCFAs). The three main SCFAs are:
Short chain fatty acids either remain in your dog’s colon or they travel into your dog’s body. Either way, they play a critical role in your dog’s health and immunity. They can:
- Feed friendly bacteria and discourage the growth of harmful bacteria
- Help form the protective mucus layer in the gut
- Keep the cells lining the gut close together (they prevent leaky gut)
- Reduce glucose levels, which protects against metabolic disease and obesity
- Build important T-cells in the immune system, which helps reduce chronic inflammation.
- Protect against food allergens
- Help the body absorb calcium, magnesium, iron and other nutrients
Since 80% of your dog’s immune system is in his gut, bacteria are critical to your dog’s health. Specifically, a diverse and well-populated bacteria population is critical to your dog’s health …
When Should You Give Your Dog Probiotics?
Because friendly bacteria support your dog’s immune system, most dogs can benefit from probiotics and probiotic foods. But there are a wide variety of health issues that can be helped by probiotics:
- Leaky gut
- Yeast (Candida) overgrowth
- Urinary tract infections
- Colitis and bowel diseases
- Allergy symptoms
- Mood disorders
Small changes to the species of bacteria living in your dog’s gut can have a noticeable impact on their host. The above diseases are all linked to shifts in the bacterial populations in the microbiome.
If your dog has a lot of diverse bacteria in his gut, these shifts are less likely to happen. Large bacteria populations mean bacterial shifts will have less of an impact on your dog’s health. But bacterial shifts happen all the time. Bacteria shifts can be caused by:
- A high starch diet
- A high fat diet
What Is The Best Probiotic To Give Your Dog?
The type of probiotic you give your dog really depends on his individual health and needs. Here are some of the best researched and most effective probiotic strains for dogs (and the amounts you should use).
1. Lactic Acid Probiotics
The vast majority of probiotic supplements are lactic acid bacteria, usually made from fermented milk. You’ll see their strain names on the supplement label, along with the species name. The Bifidobacterium and Lactobacillus species are often shown as B. Or L. So you might see B. Longum or L. acidophilus.
Lactobacillus species convert milk sugar to lactic acid, which inhibits the growth of harmful bacteria in the intestine. Like Lactobacillus, Bifidobacterium species produce lactic acid but they’re not considered a lactic acid bacteria. Bifidobacterium live in the colon and can interact with immune cells. They can crowd out harmful bacteria and help support the immune system. Low numbers of Lactobacillus and Bifidobacterium have been linked to anxiety.
Lactobacillus and Bifidobacterium probiotics are pretty fragile and they typically only last about 24 hours before they’re eliminated from the gut. But even though they’re unlikely to colonize, their DNA remains and they can still offer many health benefits.
Individual lactic acid probiotic strains include:
This is the tried and true bacteria found in most probiotics. It’s well researched in dogs and can increase Lactobacillus populations in the gut and reduce the populations of harmful clostridia. It also has a favorable effect on immune cells.
This probiotic lives in the mucus membrane of animals. It’s an important part of the gut-brain axis and can affect mood and emotions.
Lactobacillus plantarum and Lactobacillus rhamnosus
These probiotics have been studied in dogs and have been shown to have a much better surviral rate. They help build healthy colon walls in dogs with IBS and can decrease antibiotic-related diarrhea. Low levels of Lactobacillus rhamnosus have been linked to anxiety in dogs.
This probiotic has been found to be helpful for managing acute diarrhea in dogs.
This probiotic has been studied in dogs and is another one that works on the gut-brain axis. A study done by Purina found that larger numbers of Bifidobacterium longum can reduce signs of stress in dogs. B. longum can also help with diarrhea and food allergies.
Enterococci are another lactic acid bacteria that inhibits the growth of harmful bacteria in the gut. This probiotic does a better job of surviving the acidity of the dog’s gut than most Lactobacillus and Bifidobacterium species. While this probiotic is healthy for dogs, it’s come under attack recently. Scientists are worried it can cause antibiotic-resistant enterococcal infections in humans. But it’s definitely beneficial for dogs and is a well-researched addition to canine probiotics.
P. acidilactici is another lactic acid bacteria that’s showing a lot of promise in canine studies. It’s been successfully used to manage skin conditions and leaky guts.
2. Probiotic Yeast
Saccharomyces boulardii is a healthy yeast that’s considered a probiotic. Saccharomyces boulardii is used to treat acute and chronic diarrhea in humans … and a recent trial in dogs showed the same benefits. S. boulardii has also been successfully used to treat Candida and yeast. S. boulardii also helps with digestive issues caused by chronic inflammation … it can alter cell signalling pathways in the immune system.
What’s unique about S. boulardii is that it can’t be killed by antibiotics. It can be taken at the same time as antibiotic use to help protect the beneficial gut bacteria and prevent antibiotic-related diarrhea.
3. Spore Forming Probiotics
Unlike Lactobacillus and Bifidobacterium, the Bacilli strains of probiotics are spore-forming. These bacteria can form a hard coating that protects them from heat, stomach acids and most antibiotics. In fact, many antibiotics are made from soil based probiotics for this reason.
Bacilli are also called soil based probiotics because they’re commonly found in soil and water. The most common strains used include:
B. coagulans is a lactic acid producing bacteria, meaning it can crowd out unfriendly bacteria. Bacillus coagulans is also anti-inflammatory and can have a marked effect on inflammatory digestive diseases. And a 2016 study also shows that it improved rheumatoid arthritis in rats.
B. indicus is a unique probiotic … it produces large amounts of carotenoids. These are the yellow and orange pigments in plants. Carotenoids are powerful antioxidants. B. Indicus also produces B vitamins, vitamin K2 and quinols. This is an advantage for dogs with EPI and those needing digestive enzymes.
B. Subtilis is an inhabitant in the guts of healthy dogs. It was used to treat urinary tract infections before antibiotics were developed. Like B. coagulens, B. subtilis has a strong influence on the immune system. It helps produce IgA, an antibody that’s often low in dogs with autoimmune disease. IgA bolsters the gut lining and also produces vitamin K.
Are There Natural Probiotics For Dogs?
Bacteria ferment fiber and sugars … so they’re often found in foods. Common probiotic foods include:
Yoghurt is fermented milk made with the bacteria species Streptococcus thermophilus and Lactobacillus bulgaricus. There are a few problems with using yoghurt as a probiotic. First, dairy products can cause inflammation and immune issues in dogs. Second, most yoghurt contains very few probiotics. And most yoghurt is high in sugar, which can cause unwanted changes to the gut flora.
Foods such as chaga, kefir and kimchi can be a healthy part of your dog’s diet. What’s unique about fermented foods is the extremely large number of prebiotics they contain. Prebiotics aren’t particular about the species of bacteria they feed, so fermented foods can potentially feed harmful bacteria and yeast. Fermented foods can also be a problem for dogs with SIBO (small intestinal bacterial overgrowth) and yeast infections, so use in moderation and with caution.
Foods that are high in fiber are the best choice to feed beneficial bacteria populations and support a healthy gut. Healthy prebiotic additions to your dog’s food include:
- Dandelion greens
- Chicory root
- Jerusalem artichoke
Choosing A Probiotic Supplement For Your Dog
The amount of probiotic you give your dog depends on the type of probiotic you choose. For the lactic acid bacteria, you’ll want to look for a supplement with several strains. Most studies on probiotics use a mix of strains because results with single strains aren’t as good.
Because lactic acid bacteria are easily destroyed in the gut, you will need a product with a large number of colony forming units (CFU). You’ll usually want to see at least 10 billion CFU for any live probiotics to survive in your dog’s gut. This is fine for healthy dogs, but if your dog has digestive or immune problems, then look for about 25-50 billion CFU for a medium to large sized dog. Saccharomyces boulardii is much hardier than the dairy based probiotics, so a smaller amount can be given. In general, you can give a half billion to 5 billion CFU.
If you’re giving your dog spore forming probiotics, you can also use a smaller amount of CFUs because they easily survive the gut acidity. Look for about 1 billion CFU.
Do Probiotics Have Side Effects?
For the most part, probiotics are a completely safe supplement that have numerous safety studies. The most frequent side effects are digestive upset, gas and bloating.
The more frequently found issue with probiotics is that they don’t work. Here are some conditions where probiotics may not work in your dog:
Small Intestinal Bacteria Overgrowth (SIBO)
Most of your dog’s bacteria are meant to live in his colon. Small Intestinal Bacterial Overgrowth (SIBO) happens when abnormally large numbers of bacteria take up residence in the small intestine. These bacteria can interfere with digestion and nutrient absorption, which takes place in the small intestine. SIBO can be caused by a few factors, including:
- Diets that are high in sugar and carbohydrate
- Reduced gut motility
- Drugs that disrupt the microbiome (antibiotics and steroids)
It’s estimated that about 80% of people with chronic digestive issues actually have SIBO. And the number in dogs might be just as high.The symptoms of SIBO include:
- Chronic or intermittent diarrhea
- Weight loss
- Gastresophophageal reflux disease (GERD)
- IBS (or inflammatory bowel disease)
- Food intolerances
- Skin issues
- Leaky gut
Because SIBO is an overgrowth of bacteria, giving your dog probiotics will be like adding fuel to the fire … depending on the probiotic. So if your dog’s symptoms get worse with probiotics, it could be a sign he has SIBO.
Spore forming (soil based) bacteria are a better choice if you suspect your dog has SIBO. These probiotics have a protective coating that allows them to stay in their spore state until their environment is safe. This allows them to pass through the small intestine and colonize in the colon.
Probiotics After Antibiotics
This one might surprise you! A 2018 study found that giving Lactobacillus probiotics after antibiotic use caused a delay in the microbiome’s recovery. And the recovery was less complete compared to the group where no probiotics were given. The best probiotics to help restore your dog’s microbiome after antibiotics are Saccharomyces boulardii and soil based probiotics (Bacillus subtiliis and Bacillus coagulans).
How Long Should Dogs Be On Probiotics?
If you’re giving probiotics as part of a preventative health plan, then you can give them most days. Soil based probiotics are typically a better choice for everyday probiotics since they are less likely to cause SIBO.
If your dog has diarrhea, then a high CFU lactic acid probiotic should help within a few days. Some studies show that probiotics can cut the recovery time roughly in half. It’s best to continue the probiotics for a few weeks, to help resolve the underlying gut issues.
If your dog has chronic diarrhea or a digestive disorder, then a good multi-strain probiotic with gut-soothing herbs is a good choice. In this case, you’ll want to keep your dog on the probiotics long-term or until the diarrhea completely resolves.
Minamoto Y et al. Prevalence of Clostridium perfringens, Clostridium perfringens enterotoxin and dysbiosis in fecal samples of dogs with diarrhea. Vet Microbiol. 2014 Dec 5;174(3-4):463-473.
Baillon MLA et al. Effects of probiotic Lactobacillus acidophilus strain DSM13241 in healthy adult dogs. Am J Vet Res. 2004 Mar;65(3):338-43.
Fernandez L et al. Characterization of Lactobacillus rhamnosus MP01 and Lactobacillus plantarum MP02 and assessment of their potential for the prevention of gastrointestinal infections in an experimental canine model. Front. Microbiol. 24 May 2019.
Kirchoff NS et al. The gut microbiome correlates with conspecific aggression in a small population of rescued dogs (Canis familiaris). PeerJ. 2019;7:e6103.
Russell KL, MS et al. Clinical benefits of probiotic canine-derived bifidobacterium animalis strain AHC7 in dogs with acute idiopathic diarrhea. 2019 Mar 8.
Lewellen H, DVM et al. Boosting tranquility through nutrition. 2016 Apr 26.
Strompfová V et al. Selection of enterococci for potential canine probiotic additives. Vet Microbiol. 2004 May 20;100(1-2):107-14.
Hammerum AM et al. Enterococci of animal origin and their significance for public health. Clinical Microbiology and Infection. 2012 Jul;18(7):619-625.
Bakal G et al. Naturally speaking – probiotics going to the dogs. 2017 Apr 6.
D’Angelo S et al. Effect of Saccharomyces boulardii in dog with chronic enteropathies: double-blinded, placebo-controlled study. Vet Rec. 2018 Mar 3;182(9):258.
Abhari K et al. The effects of orally administered Bacillus coagulans and inulin on prevention and progression of rheumatoid arthritis in rats. Food Nutr Res. 2016 Jul 15;60:30876.
Konuray G et al. Potential use of Bacillus coagulans in the food industry. Foods. 2018 Jun; 7(6): 92.
Felix AP et al. Digestibility and fecal characteristics of dogs fed with Bacillus subtilis in diet. Cienc. Rural. 2010 Oct;40(10).
Suez J et al. Post-antibiotic gut mucosal microbiome reconstitution is impaired by probiotics and improved by autologous FMT. Cell. 2018 Sep 6;174(6):1406-1423.e16.
Kelley RL et al. Safety and tolerance of dietary supplementation with a canine-derived probiotic (Bifidobacterium animalis strain AHC7) fed to growing dogs. Vet Ther. Fall 2010;11(3):E1-14.