Probiotics … they’re the new fad in dog health. But is there reason to rethink the fad?
The answer is a resounding maybe!
Truth is, sometimes probiotics can help your dog and sometimes they can’t. And sometimes they can even harm your dog.
So before you reach for the probiotics, let’s take a moment to look at their job and why they sometimes don’t work.
Or worse yet, when probiotics can harm your dog …
Post At A Glance
1. Your dog’s bacteria and what they do
2. What do bacteria eat?
3. How the gut supports your dog’s immune system
4. When bacteria cause harm
5. The signs of dysbiosis
TYPES OF PROBIOTICS
6. Lactobacillus and Bifidobacterium
7. Saccharomyces boulardii
8. Soil based probiotics
9. How much probiotics to give your dog
WHEN PROBIOTICS CAN’T HELP YOUR DOG
10. Small Intestinal Bacteria Overgrowth (SIBO)
11. After antibiotics
12. Lack of bacteria
REPAIRING THE MICROBIOME
13. How diet affects gut bacteria
14. Why probiotics are important
15. Polyphenols and gut health
The Family That Eats Together Stays Together
Have you ever seen sea birds around a fishing boat? Birds and fishermen have a symbiotic relationship that’s mutually beneficial.
Birds alert fishermen to activity under the water. They tell them where the fish are. And the birds benefit because they get scraps from the fishermen after they make their catch.
Your dog has a similar relationship with the bacteria that live on and inside him. In fact, for every cell in your dog, there are about 10 bacteria.
In humans, that amounts to about 4 pounds of bacteria … in comparison, the liver is only 2-3 pounds! So the microbiome is one very large and important organ.
Many of the bacteria in your dog’s gut have a symbiotic relationship with your dog. They benefit because they get to eat some of your dog’s food and have a safe neighborhood to hang out in.
And your dog benefits because his gut bacteria can improve his health.
Most of the bacteria in your dog’s gut are called commensal bacteria. In Latin, commensal means “to eat at the same table.”
And that’s a good way to describe them … as long as they stay in the gut (and we’ll talk about that a bit further down).
But first, let’s take a quick look at the symbiotic relationship between your dog and his bacteria.
The Intestinal Microbiome
Bacteria live in all parts of your dog’s digestive tract. There are just a few that live in the stomach and as you travel from the small intestine to the large intestine, the numbers increase.
But, by far, most of the bacteria live in your dog’s colon. Remember that, because if bacteria leave the colon, trouble can start.
The types of bacteria also change as you move down the digestive tract.
All animals (and people) have the same 6 bacteria phyla (or families) in their guts:
These phlya make up 99% of all of the gut bacteria.
There might be only a few phyla, but each phyla contains a lot of different bacteria types. In fact, it’s estimated there are several thousand strains of bacteria in the intestines.
This complex community of bacteria and other microorganisms in your dog’s gut is called the microbiome. The microbiome also includes yeasts and viruses but is mainly bacteria.
These bacteria all function together and they work just like any other organ in your dog. In fact, scientists call the microbiome “the forgotten organ.”
Here are some of the bacteria families found in the top three phyla:
Collectively, these bacteria are called your dog’s microbiome. And each microbiome is unique to each dog, just like a fingerprint.
And that’s because every dog is exposed to a unique environment and diet …
What Do Bacteria Like To Eat?
Every time your dog eats, he’s not just feeding his cells … he’s also feeding his the bacteria inside him.
Bacteria eat exactly what your dog eats.
The commensal (friendly) bacteria love one food in particular: fiber. That’s because your dog can’t digest fiber so it passes undigested to the colon, leaving a lot of food for the good guys.
There are three 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).
Insoluble fiber doesn’t become hydrated. But it’s fermented by bacteria in the colon. Cellulose is an example of insoluble fiber.
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. Technically, they ferment them.
And then the magic happens …
How Bacteria Support The Immune System
When bacteria eat fiber, they “poop out” magical little byproducts called short chain fatty acids (SCFAs). The three main SCFAs are:
Short chain fatty acids either remain in your dog’s colon or they travel out of your dog’s body. Either way, they play a critical role in your dog’s health and immunity:
- SCFAs feed and grow more commensal bacteria and discourage the growth of harmful bacteria
- SCFAs help form the protective mucus layer in the gut
- SCFAs keep the cells lining the gut close together (they prevent leaky gut)
- SCFAs reduce glucose levels, which protects against metabolic disease and obesity
- SCFAs (especially butyrate) build important T-cells in the immune system, which helps reduce chronic inflammation.
- SCFAs protect against food allergens
- SCFAs help the body absorb calcium, magnesium, iron and other nutrients
Besides producing SCFAs, commensal bacteria play other important roles in the dog. Commensal bacteria will:
- Form a protective barrier against toxins, heavy metals and allergens
- Produce enzymes for digestion
- Produce B vitamins
- Change the genetic expression of cells
- Contribute up to 90% of the body’s immune system
- Crowd out unwanted bacteria and fungi
- Produce serotonin and impact mood
- Talk directly to the brain and support its function
- Prevent dental disease
- Help with vaginitis
So bacteria are critical to your dog’s health. And you might be reaching for the probiotics because you want more of these good guys, right?
Well, hang on to those probiotics for now … there’s still more to learn first!
When Bacteria Go Rogue
Small changes to the species of bacteria living in your dog’s gut can have a noticeable impact on their host.
Sometimes friendly bacteria can compete with their host for nutrients … and they produce toxic byproducts. Some Lactobacillus and Clostridium species break down bile and produce bile acids that can damage the gut lining.
If pathogenic bacteria grow out of control, they will crowd out commensal bacteria.
When this happens, less butyrate will be made and this down-regulates proteins that keep the junctions between epithelial cells tight … so the permeability of the small intestine will increase.
This is called leaky gut.
When leaky gut happens, lipopolysaccharides (or LPS) can travel into the bloodstream. LPS is found in the outer membrane of bacteria such as clostridium, enterococcus and bacteroides … and when the bacteria are broken down, they release toxic LPS into the small intestine.
This happens regularly because a lot of bacteria die off after the food they’re in is eaten. Typically, the LPS stays in the lumen of the intestine. But if there’s leaky gut, the LPS will get through the intestinal wall and enter the circulation.
This creates low-grade inflammation throughout the entire body … and this process is called metabolic endotoxemia.
Scientists are linking metabolic endotoxemia with:
So these diseases are all linked to shifts in the bacterial populations in the microbiome.
Now, 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:
- Diet (We’ll get to that soon)
And when the bacterial shift affects your dog’s health, it’s called dysbiosis. But defining dysbiosis is hard. Remember, each dog’s microbiome is like a fingerprint … so it’s hard to know what a normal, balanced microbiome looks like when each one is different.
But there are a few things we can hang our hat on …
What Does Dysbiosis Look Like?
The symptoms of dysbiosis often happen in the gut. But once leaky gut happens, you can see symptoms in other parts of the body.
The common signs of dysbiosis include:
- Chronic or intermittent diarrhea
- Bad breath
- Gas and bloating
- Changes in mood (aggression or anxiety)
- Food sensitivities
- Leaky gut
And if the toxic LPS from bacteria is allowed to enter the bloodstream, chronic inflammation will follow. This can lead to:
- Nutrient deficiencies (including B vitamins, minerals and fat soluble vitamins)
- Cognitive decline
- Autoimmune disease
And these issues will cause more inflammation of the gut lining … which starts the cycle all over again.
Are you ready for those probiotics now?
Can Probiotics Help Your Dog’s Gut Health?
The definition of a probiotic is a live microorganism that can colonize in the host and provide health benefits.
There are quite a few benefits to adding probiotics to the diet:
- Probiotics compete with pathogenic bacteria and crowd them out.
- Probiotics can produce healthy SCFAs.
One of the arguments used against probiotics is that they can’t survive the pH of the gut and essentially die once they reach the intestines … or that they don’t colonize even if they’re viable when they reach the intestines.
But some scientists believe only their DNA needs to survive for there to be health benefits. And they think that even dead probiotics can cause immune changes in the host, which is interesting.
In 2003, Purina compared the feces of dogs eating identical commercial diets for a 1 year period. One group of dogs had probiotics added to it.
When they compared the two groups, the scientists found the dogs fed the probiotic had a lot more IgA antibodies in their gut compared to the control group. These are immune cells produced by commensal bacteria that bolster the gut lining. The dogs fed probiotics also had much larger numbers of IgA and IgG antibodies for the vaccine strain of distemper compared to the controls.
And this is just one of probably a thousand studies showing that probiotics can boost health and the immune system … even if the probiotics only live a few days.
Here are some of the common probiotics and how they can help your dog.
Types Of Probiotics For Dogs
There are really three main types of probiotics you can give your dog. And all have different properties.
There are 3 types of Probiotic you can use in your dog … all with different benefits:
1. Lactobacillus and Bifidobacterium (dairy based probiotics)
2. Saccharomyces boulardii (a beneficial species of yeast)
3. Soil Based Probiotics (spore forming probiotics that produce vitamins and antioxidants)
If you understand the differences in probiotics, it will help you choose the best one for your dog. So here goes …
1. Lactobacillus and Bifidobacterium
The vast majority of probiotic supplements are lactic acid bacteria 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.
The probiotics made from milk tend to only last about 24 hours before they’re eliminated from the gut.
Let’s look at each one separately …
Lactobacillus species convert milk sugar to lactic acid and are in the Firmicutes phylum. The lactic acid inhibits the growth of harmful bacteria in the intestine.
But too much Lactobacillus might be an issue …
A 2019 study found that dogs with aggression had larger numbers of Lactobacillus.
Bifidobacterium belongs to the Actinobacteria phylum. 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.
Here are some common strains of Lactobacillus and Bifidobacterium found in probiotics … and their results in dogs:
Lactobacillus acidophilus and Bifidobacterium
These are common dairy based probiotics. This can be a problem if your dog has a dairy allergy. But they can help manage yeast and support the immune system.
Low numbers of Lactobacillus and Bifidobacterium have been linked to anxiety.
Most Lactobacillus and Bifidobacterium need to be refrigerated because they’re dairy based and pretty fragile. This makes is hard for them to survive the dog’s gut when they’re eaten but research shows they can survive and last a day or so.
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 from the Firmicutes phylum. Remember, the lactic acid they produce 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 the 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.
Bacteria ferment fiber and sugars … so they’re often found in foods. Common probiotic foods include:
Fermented foods are mainly rich in the lactic acid Lactobacillus and Bifidobacterium species.
Dogs don’t make as much of the enzyme (lactase) that digests lactose as people do. So be cautious with dairy-based foods as they can cause digestive upset in your dog.
2. Saccharomyces boulardii
Saccharomyces boulardii is actually a healthy yeast and not a bacterium. But it’s still 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.
This probiotic is unique in that it can’t be killed by antibiotics … so it can be taken at the same time as antibiotic use to help protect the beneficial gut bacteria.
S. boulardii also helps with digestive issues caused by chronic inflammation … it can alter cell signalling pathways in the immune system.
So this friendly little yeast is a great consideration for most dogs … it’s a good addition to your dog’s probiotic.
3. Soil Based Probiotics (or Organisms)
Soil based probiotics are usually found as Bacillus strains. As their name suggests,they’re found in the soil and in water.
Unlike Lactobacillus and Bifidobacterium, soil based probiotics are spore-forming. This means they 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.
The soil based probiotics’ protective coating means they don’t need to be refrigerated. And unlike most probiotics that come from dairy (like Lactobacillus and Bifidobacterium), soil based probiotics are hypoallergenic. That’s good news for dogs with dairy allergies.
Soil based probiotics are also well researched. 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 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.
Recommended Dose For Probiotics
The amount of probiotic you give your dog depends on the probiotic you choose.
For Lactobacillus and Bifidobacterium, 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 positive.
Because they are easily destroyed in the gut, look for a large CFU (colony forming units) with Lactobacillus and Bifidobacterium. You’ll usually want to see at least 10 billion CFU for any live probiotics to survive in your dog’s gut.
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.
For soil based probiotics, you can also use a smaller amount of CFUs because they easily survive the gut acidity. Like dairy-based probiotics, soil based probiotics work best with more than one strain. Look for about 1 billion CFU. Higher CFU counts aren’t better in all cases.
So there you have it. Probiotics can deliver some important health benefits to your dog. But each probiotic has a different job … so your job is to understand each probiotic and how it works.
But probiotics can have limitations … and you have to be aware of this!
When Probiotics Can’t Help Your Dog
You might have given your dog probiotics for months … and you’ve seen no changes in his health. You might have even seen his symptoms worsening.
The truth is, there are some instances where probiotics can’t help your dog.
Here are a couple of reasons your dog’s probiotics might not work:
1. Small Intestinal Bacteria Overgrowth (SIBO)
Most of your dog’s bacteria are meant to live in his colon. On the other hand, the small intestine normally houses just a few bacteria.
Small Intestinal Bacteria Overgrowth (SIBO) happens when abnormally large numbers of bacteria take up residence in the small intestine. Large amounts of bacteria will interfere with digestion and nutrient absorption.
It’s estimated that about 80% of people with chronic bowel 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
SIBO can be caused a a few factors, including:
- Diets that are high in sugar and carbohydrate
- Reduced gut motility
- Drugs that disrupt the microbiome (antibiotics and steroids)
Because SIBO is an overgrowth of bacteria, giving your dog probiotics will be like adding fuel to the fire … depending on the probiotic.
Most of the bacteria living in the small intestine are Lactobacillus or Bifidobacterium species. Since most probiotics contain these bacteria, they’ll just make things worse.
So if your dog’s symptoms get worse with probiotics, it could be a sign he has SIBO.
But soil based probiotics are different …
Soil based probiotics are spore forming … and this protective coating allows them to stay in their spore state until their environment is safe. Which is in the large intestine and colon.
So soil based probiotics are still a good option for dogs with SIBO because they don’t populate the small intestine.
2. 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 exception might be Saccharomyces boulardii but research still needs to be done.
3. Lack Of Diversity/Lack Of Bacteria
One of the reasons why probiotics delayed recovery from antibiotics could be because they don’t do much to increase the numbers of bacteria in the large intestine and colon. Or the diversity.
There are two significant issues with probiotics for dogs:
- Probiotics don’t colonize for more than a few days
- Probiotics aren’t always the same strains found in dogs
Your dog’s microbiome is as individual as he is. It’s a diverse community of thousands of different bacteria, fungi and viruses, all working together to fuel his health and immune system.
So while giving him a few strains of probiotics can help him recover from health challenges … they won’t do much to make any significant changes in his microbiome.
Probiotics have a place in your dog’s health care regimen … they can help him recover from a number of health issues.
But probiotics can’t fix a broken microbiome.
Using probiotics to fix the trillions of bacteria and thousands of species in your dog’s gut would be like using a cup of water to fill your bath tub.
It’s not enough …
So your job doesn’t end with the probiotics … if your dog’s commensal bacteria are fighting a losing battle, you have to bring in the heavy artillery if you want to win the war!
Here’s how …
Fixing The Microbiome For Good
Researchers found that the microbiomes in healthy dogs and cats have three things in common:
- Lots of bacteria
- Diverse populations of bacteria
- The right balance of bacteria
While probiotics carry health benefits, they can’t do the whole job. To be healthy, your dog’s microbiome should contain a crowded, diverse population of microbes.
And there are two important ways to make that happen …
1. Use Diet To Bolster Gut Bacteria
You might not know this, but your dog’s diet can have a tremendous impact on his gut health. And that’s because you don’t just feed your dog … you also feed his little friends. They even lend your dog enzymes to help digest his share of the food.
So if you want to balance your dog’s microbiome, you have to pay attention to his diet. There is no other factor that can have as large a positive impact on your dog’s gut health.
Arguably, the most important bacteria phylum in your dog is Bacteroidetes. Members of this family are the bacteria that produce the SCFAs that balance and fuel your dog’s immune system. SCFAs also help prevent leaky gut.
Bacteroidetes species love to eat protein … so feeding your dog a diet high in protein will help grow these beneficial colonies.
If the dog’s diet is high in fat and starch, then it will feed the Firmicutes species. Firmicutes accounts for about half of the healthy dog’s microbiome. But if Firmicutes populations grow out of control, they will crowd out Bacteroidetes and increase inflammation in the gut. This deteriorates the integrity of gut lining, allowing toxins to travel into the blood.
This is called metabolic endotoxemia.
Researchers are starting to look at how dog diets can impact their microbiomes. A 2017 study found that dogs eating a raw diet had a microbiome that was consistently different from kibble-fed dogs. And the microbiomes of raw fed dogs contained more bacteria and were more diverse. They also contained fewer Firmicutes species.
So feeding your dog a raw, high protein diet that’s low in fat and sugars can have a profound impact on his gut health. And feeding a wide range of foods can create a more diverse microbiome.
Which brings us to another important piece of the diet puzzle …
2. Don’t Skimp On The Prebiotics
Prebiotics are fibers your dog can’t digest. Many of the healthy bacteria species that produce SCFAs love to eat fiber.
So next to diet, prebiotics are one of the most important additions to your dog’s probiotic plan. They can often do a better job of restoring gut bacteria diversity than probiotics.
A 2007 study gave puppies with Salmonella prebiotics and found they produced more SCFAs, had less gut damage and produced more Lactobacilli.
But, like probiotics, you need to give your dog more than one prebiotic.
There are thousands of species of bacteria in your dog’s gut … all with different food preferences. So offering your dog a wide variety of prebiotics will do the best job of building diverse bacteria populations.
Some of the best sources of prebiotics for dogs include:
Prebiotics, as you can see, only come from plant sources. So if your dog isn’t eating vegetation, his gut health will suffer.
And there’s one more reason to add vegetation to your dog’s diet …
3. Polyphenols Build Microbiomes
Polyphenols are antioxidants that give plants their bright yellow, orange and red colors. They’re like feeding your dog a rainbow … and there’s a pot of gold at the end.
While polyphenols are powerful antioxidants, 95% of them travel undigested to the colon. It’s there that their special two way relationship begins.
Polyphenols can change the bacteria populations in the microbiome … especially the critical balance between Bacteroides and Firmicutes. Polyphenols can also bind to and alter the membranes of pathogenic bacteria and interfere with their activity and growth.
Plus, the antioxidant properties of polyphenols make them useful for treatment inflammatory gut diseases.
So if you want significant, lasting changes to your dog’s gut health, it’s important to pay attention to his diet and add vegetation.
Putting It All Together
If your dog suffers from virtually any chronic or inflammatory disease … chances are, it’s the result of a microbiome gone rogue. There might be too few bacteria, too many bacteria in the small intestine, not enough diversity, or the wrong balance of bacteria.
Either way, your dog needs your help.
Probiotics are in important part of your health plan. They can help fight pathogenic bacteria and even support your dog’s immune system. But they don’t live long in your dog, so they need to be taken daily.
Probiotics also can’t boost the numbers of diversity of bacteria in your dog’s microbiome.
To shift the microbiome, you need to evaluate your dog’s diet … and add a good amount of vegetation that’s rich in fiber and polyphenols.
This three-pronged approach of probiotics-diet-vegetation will help restore health to your dog’s microbiome … and to your dog.