What are probiotics?
Probiotics are microorganisms (usually bacteria) that are consumed for health benefits. These can be found in foods like yogurt and fermented foods, or provided as a supplement. Some of the most common strains of bacteria used in animal probiotics belong to the genera Enterococcus, Bifidobacterium, and Lactobacillus. To give you an idea of relatedness, Enterococcus and Lactobacillusare as related as cats are to dogs, while Bifidobacterium would be the equivalent of a sea urchin. This wide difference between the probiotic strains available means that many strains have very different properties from one another.
Modern society needs more good bacteria
You may be familiar with the general landscape that drives our need for “good” bacteria: Our modern, sterile society is plagued with problems like allergies and digestive disorders that are linked to inflammation and the immune system. It turns out that hygienic lifestyles and processed foods result in both us and our pets not encountering as many microbes as our ancestors. Although this means we are exposed to fewer pathogens, we are also robbed of countless encounters with harmless and potentially beneficial microbes in the natural world. This can result in malfunctioning immune systems and low diversity in our gut microbiomes (the hundreds to thousands of different types of microbes living in the digestive system).
What probiotics can do
Probiotics can provide relief from acute cases of diarrhea
There have been many studies testing the ability of probiotics to help resolve diarrhea in cats and dogs. The results range from no effect to a large effect, depending on which study you look at. Overall, there is evidence that some probiotic strains can help cats and dogs recover quicker from acute diarrhea, particularly stress-induced diarrhea.
Probiotics can affect the immune system
This is also overall evidence that probiotics affect the immune system of animals. One complication is that different probiotic strains can have very different effects on the immune system. For instance, a popular Enterococcus strain appears to stimulate the immune system, whereas other popular strains can have anti-inflammatory or modulating properties. There is not currently enough evidence to suggest one probiotic strain over the other for different health problems.
What probiotics cannot do:
Probiotics cannot restore gut bacteria diversity
There is not sufficient evidence to support the frequent claim that probiotics repopulate guts with healthy microbes. The vast majority of studies that have tested probiotics in humans and our pets have found that probiotics do not stick around in digestive tracts once their use is stopped.
Even if a probiotic can persist in the gut microbiome, this does little to restore diversity to the gut. Probiotics are only one, or a mixture of a few, specific types of bacteria. A healthy gut microbiome contains hundreds or thousands of different types of bacteria. Using probiotics for an imbalanced gut microbiome is like trying to regenerate a rainforest by planting a large number of pine trees.
Probiotics cannot be held to the same standards as drugs
Probiotics are consumed for their supposed health benefits. However, because they are supplements and not drugs, they do not have to prove their effectiveness. Moreover, these supplements often do not contain their listed ingredients. In an independent study, 25 veterinary probiotics were scientifically evaluated: Only two of these probiotics had labels that accurately described their contents. Because of the lack of regulation, it can be confusing choosing a probiotic for your pet. When trying probiotic supplements, keep in mind that probiotics are not equivalent. Ask your veterinarian for suggestions if you’re uncertain what brands to try.
Will probiotics help your dog or cat?
At AnimalBiome, we’ve heard numerous stories from our community about dogs and cats that were helped by probiotics. Many owners like to feed their pets probiotics during and after antibiotic treatments, or as a supplementary treatment to a digestive disorder. Others use probiotics to alleviate stress-associated digestive upsets (like during kenneling). However, because probiotics rarely have long-term effects on the microbiome, probiotics are generally not a solution for chronic digestive disorders related to imbalanced gut bacteria.
If your pet is suffering from a chronic digestive disorder, you should consider testing your dog or cat’s gut bacteria. Probiotics may provide temporary relief, but better treatment options exist if your pet is suffering from a microbiome imbalance. One treatment that is growing in popularity is a fecal transplant. This procedure delivers hundreds of different types of microbes from a healthy donor to a suffering pet’s digestive tract. If you think your pet may benefit from a more balanced gut microbiome, check out our oral FMT pills for cats and for dogs that can be administered in the comfort of your own home.
To learn more about fecal transplant therapies for your pet, check out The Potential of Fecal Transplants.
Adrien Burch, PhD, is a co-founder of AnimalBiome