by Jillian LaCross
The scientific age in which we live may be overwhelming at times, but it also has its benefits, particularly for our four-legged friends. We are coming to better understand the essential nature of gut health and its relationship to overall health. Probiotics are a big part of the conversation, and veterinary medicine is advancing its approach to canine care thanks to a lot of new veterinary research on the subject.
Understanding Probiotics and Canine Gut Health
Probiotics are a component of maintaining a healthy gut, as well as realigning it when things cause it to not work as optimally. “Seventy percent of the immune system is in the GI tract, so your gut health really is the gateway to overall health,” explains Dr. RuthAnn Lobos, DVM CCRT CVAT, Senior Veterinarian, Nestle Purina PetCare. “And from the veterinary aspect, it’s a good reflection of what’s going on with the rest of the body, if we can better understand what’s going on with the GI tract.”
The gut is where nutrients are absorbed, giving canine bodies what they need to live healthy lives. However, if the gut isn’t doing this, that can mean losing too much water or feeling like energy is zapped. For dogs, “that also then starts to reflect on muscle health, skin health, and brain health. All of that foundationally starts with the absorption of nutrients at the gut health level. And we are learning more and more about the whole ecosystem that exists, that whole microbiome,” explains Dr. Lobos.
“When we look specifically at gut health, we’re learning that that microbiome, which is made of bacteria and viruses and protozoa and all of these living organisms, in the right little happy balance when things are coming along, not only affects digestion, but it can also have impacts on things like mood and anxiety levels.”
That’s where incorporating probiotics, or live bacteria, comes into play. “Probiotics can support a healthy gastrointestinal microbiome, which in turn helps with digestion, stool quality, and nutrient absorption,” explains UK veterinarian Dr. Emma Chandley, BvetMed, PGCertSas MRCVS.
Dr. Lobos further explains that there are a lot of “biotics.” There are the prebiotics, which is food for the natural microflora in the gut. In dog food, that can look like chicory root on the nutrition label. It’s a fiber source. Then there are the probiotics, which are good and necessary, but can be perceived as “bad” if something has gotten out of balance. Finally, there is an emerging space called postbiotics. “These were bacteria that were once alive and now were purposely killed. So usually that’s done through radiation or freeze drying or things of that nature. Those postbiotics then get added to the food. They work differently but still support gut health in our dogs” explains Dr. Lobos. “I love to use the analogy of, if you think about the GI tract as a lawn, your prebiotics are like fertilizer for the grass, the probiotics are the grass seed, and your postbiotic would be like compost.”
This knowledge and all the subsequent research have made a difference in how veterinarians treat dogs that come into their clinics with GI upset. “I graduated vet school in 2003, and it was kind of the gold standard that when there was a dog that came in with diarrhea, you put the dog on metronidazole, it’s also called Flagyl. Maybe you change their diet for five to seven days, and you send them out the door,” reflects Dr. Lobos. But that’s not where we are today. “As we are looking at the effects of antibiotics on that GI microbiome, even metronidazole or Flagyl that does have not only antibacterial, but also anti-inflammatory effects in the GI tract, we know that it is permanently changing the gut microflora. So there’s been proof now that if there is GI upset, if the dog is otherwise happy, healthy, running around, isn’t lethargic, doesn’t have a fever, those sorts of things, the first treatment should be a probiotic and, or if warranted, a short diet change to something highly digestible.”
Probiotics can be an important line of defense as well as a way to try to reorient a dog’s systems without the use of medicine. However, this should be done with the input of your veterinarian. Adds Dr. Chandley, “The evidence base is still developing, and probiotics shouldn’t be seen as a cure. If they are used appropriately and under vet guidance, they can be a helpful adjunct, but good clinical assessment and tailored treatment remain key. We’re moving away from a one-size-fits-all approach toward more targeted use of specific strains for specific conditions, which is encouraging.”
Choosing the Right Probiotic
Probiotics might seem like an easy, “natural” thing you could pick up at the pet supply store without bothering your vet; however, to Dr. Chandley’s point, specific strains can have an impact on different conditions. So, how do you know which one to choose?
According to Dr. Lobos, “It is very important to do your research and also talk to your veterinarian about which probiotic is good and good for your specific dog. The supplement industry is kind of like the Wild, Wild West,” she explains. “They do not have to go through an approval to put a probiotic on the market. There are several studies out there that have randomly pulled twenty-five probiotics off the shelf, looked at them for not only accuracy of the spelling of the bacteria and the actual bacteria in the product, but then the concentration of that bacteria. There were mismatches galore. When we as vets make a recommendation of a supplement, it’s our license that’s on the line, so most vets are going to do their due diligence and research the company behind that probiotic.” That’s why it’s so important to speak to your vet before you give your Lab anything.
It’s a similar story in the UK. “The bigger issue in the UK market is variability in product quality, different strains, doses, and viability, so it’s sensible to choose a reputable, evidence-based veterinary product rather than using multiple supplements together,” says Dr. Chandley.
Human probiotics aren’t a viable substitute either. Dr. Lobos has experienced sick dogs for that very reason. “First and foremost, when you choose to give your dog probiotics, know that you’re not going to cause more harm than good. And then secondly, know that you’re actually spending your money on something that is going to be effective for your pet [by talking to your vet and getting the appropriate probiotic].” A particular strain of a particular probiotic can make a big difference.
What’s normal when you start your dog on probiotics for the first time or after an absence? “It’s not unusual to see mild, transient changes such as slightly softer stools or increased flatulence for a few days as the gut microbiome adjusts, but this should settle quickly. Persistent diarrhea, vomiting, lethargy, or any systemic signs wouldn’t be expected and should prompt stopping the product and seeking veterinary advice,” explains Dr. Chandley.
Dr. Lobos points to the consistency of a dog’s stool (see “The Scoop on Poop” in the July/August 2024 of Just Labs). Depending on its appearance, it might reveal that a probiotic isn’t working and that you need to talk to your vet.
The Right Time to Add Probiotics
As already mentioned, if a vet is presented with a dog with GI upset but has no other concerning symptoms, then probiotics are a common first line of treatment. “For some dogs, they can be useful during periods of mild digestive upset, dietary change, or stress. That said, in a completely healthy dog on a stable, good-quality diet, the benefits may be fairly subtle,” says Dr. Chandley.
Dr. Lobos uses probiotics for her own sporting Lab, who sometimes makes questionable decisions regarding what’s fit for consumption and could experience digestive upset as a result. “There will be times where we’re going on a break and I know that there’s going to be temptation, or we’re going on a road trip. I’ll start on a probiotic, not that it’s necessarily a guarantee, but I’m just going to boost his GI tract and maybe give him a little extra balancing power if he does make an unusual dietary choice while we’re out there,” she says. “And then certainly, I will give him that probiotic through the road trip, then a day or two after when we get home, just to, again, try to help keep that balance and stave off any GI upset that may occur from all the fun and adventure of travel and the new places and spaces that we’ve explored.”
Outings, travel, kennel stays, and exercise are natural stressors to the GI tract. Probiotics can help keep a healthy gut in a healthy state. “If your dog is doing a lot of things, maybe they’re going on road trips with you, they’re your running buddy, your hunting buddy, hiking buddy, and they’re exposed to various environments, having them on a probiotic certainly is a good thing to consider from a support factor,” explains Dr. Lobos.
Dr. Chandley agrees and also notes, “Starting a probiotic a few days before a predictable stressor, such as kenneling, travel, or a change in routine, can potentially be beneficial in reducing the risk of stress-related diarrhea. They can then be continued during the stressful period and stopped afterwards if no longer needed.”
Working and athletic dogs, such as if your Lab participates in hunt tests, agility, or dock diving, or has a career as a working or therapy dog, “are more prone to physiological stress, which can impact gut health and lead to looser stools or inconsistent performance,” says Dr. Chandley. “Probiotics may help maintain gastrointestinal stability during periods of travel, competition, or increased workload. However, they’re not a substitute for appropriate conditioning, nutrition, and hydration, which remain the priority.”
Age isn’t a factor; however, age is a consideration as to which probiotic to choose. Puppies receive a lot of vaccinations in the first year of life, and Dr. Lobos pointed to a study conducted with puppies, with one group receiving probiotics and the other going without. “We looked at it in puppies as young as three weeks of age, and then also looked as they were eight weeks of age through a year old, and looked at their responses to vaccinations. What it showed us was not that the probiotic made their immune system go into hyperdrive. When those puppies had FortiFlora [a Purina product] on their diet daily, their immune system didn’t see the dip as big as it did when they weren’t for the group of puppies that were not on the FortiFlora,” explains Dr. Lobos. “For our senior dogs, we do know that the diversity in their GI tract starts to decrease. We know with a less diverse microflora population, there is increased susceptibility to GI upset because the immune system is aging as well.” There are benefits to using probiotics across the lifespan of your Lab.
There are circumstances when probiotics may not be recommended, despite their clear benefits for gut health. “I would be more cautious in severely immunocompromised dogs, those with critical illness, or in cases with significant intestinal barrier compromise. In these patients, any supplementation should be discussed with the attending vet on a case-by-case basis,” says Dr. Chandley.
Your vet, knowing the condition of the dog and the potential complications of the disease, is essential for making that decision. “There are some places and spaces, like, if they’re going through chemo because they have cancer, sometimes we’ll recommend a probiotic because some of the GI side effects that are associated with chemotherapy. But sometimes it may be if they’re too sick for chemotherapy and their immune system is too suppressed, then we don’t give a probiotic because it is a live bacteria and we don’t want anything going haywire and making a problem worse,” explains Dr. Lobos.
Sometimes, a GI issue, once treated with a probiotic, may reveal there’s a larger health issue at play for your Lab. “It’s important not to overlook underlying disease. Chronic gastrointestinal signs should always be properly investigated rather than repeatedly managed with supplements alone,” recommends Dr. Chandley.
Probiotics can be an effective way to maintain or boost your Lab’s gut health as well as his immune system. However, it cannot be understated how important it is to do this in cooperation with your vet. Your Lab’s age, lifestyle, and overall health (such as a chronic condition) are all factors in the proper selection of a probiotic supplement. And, you want to support your Lab the best that you can. “Owning a dog is expensive enough. Let’s make sure we’re using our dollars wisely and effectively,” advises Dr. Lobos.
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RuthAnn Lobos, DVM, CCRT, CVAT, is the Senior Veterinarian for Nestlé Purina PetCare. She joined Purina in 2005 as Veterinary Communications Manager for Purina Pro Plan Veterinary Diets. Dr. Lobos managed Global Scientific Programs and Events for the Purina Institute for four years, during which time she was an integral part of the Institute’s signature Companion Animal Nutrition Summit. Dr. Lobos received her certification in canine rehabilitation and veterinary acupuncture through the Canine Rehabilitation Institute in 2010 and 2021, respectively. She is an active member of the American Veterinary Medical Association, American Academy of Veterinary Nutrition, American Association of Rehabilitation Veterinarians, and Colorado Veterinary Medical Association. Dr. Lobos lives in Boulder, Colorado, and spends her evenings and weekends practicing as a relief veterinarian. Outside of work, she is an avid marathoner and triathlete and also enjoys upland game hunting, working with sporting dogs, hiking, and camping with her son. Her canine companions are a hard-charging yellow Labrador retriever named Finn and a lovable wirehaired pointing griffon named Journey. Dr. Lobos can be found on Instagram and TikTok (@petvetruthann).
Emma Chandler, Bvetmed PgcertSAS MRCVS, is a graduate from the Royal Veterinary College in London. After completing her degree she went on to work in general practice while studying for a postgraduate certificate in Small Animal Surgery. Emma is an experienced veterinary surgeon with a passion for sharing her knowledge and expertise on all aspects of animal health and care. From advanced surgical procedures to everyday pet concerns, she enjoys helping and supporting owners with practical, compassionate advice. Outside of work, Emma stays busy caring for her dog and two pygmy goats at home.
