Probiotics are beneficial bacteria that naturally inhabit the intestines of all animals. These microorganisms help with vitamin and mineral absorption, with maintaining balance in the gut, and with producing certain vitamins–particularly those of the B vitamin group–for their host. These beneficial bacteria can also prevent bad bacteria from colonizing the gut, and can boost immunity. How? The gastrointestinal tract is part of the body’s first line of defense, and the probiotic bacteria help with controlling bad bacteria, yeast, and viruses by outcompeting them for food and living space, and by making the intestines a less hospitable place for those bad bacteria.

When the balance of these natural microorganisms is off, a variety of gastrointestinal disturbances can occur. Flatulence, diarrhea, yeast infections, and poor digestion are all potential signs that the natural balance of these organisms has been disrupted. Feeding improper diets can throw off the natural balance of these organisms, as can taking antibiotics, traveling, switching foods, or changes in stress levels.

Probiotic supplements are often used to help ease transitions to new and better foods, to help prevent stomach upset and diarrhea during travel and times of stress, and to counteract the effects of aggressive antibiotic therapy. Many dog owners also regularly supplement their dogs’ diets with yogurt to provide doses of beneficial bacteria, primarily those of the Lactobacillus species. But is supplementation with probiotics actually effective?

What researches have found is that certain strains of probiotic bacteria can be very effective in dogs. The probiotic Enterococcus faecium is actually the most beneficial strain for dogs. It has a greater effect for long-term supplementation, creating an increase in the numbers of E. faecium intestinal bacteria that lasts for several weeks. Supplementation with Lactobacillus and Bifidum species–both commonly used in yogurt and human probiotic supplements–can help during bouts of diarrhea in dogs, but their effect is very short-lived compared to that of E. faecium.

If your dog has a condition that may benefit from probiotic supplementation, then how do you choose a good supplement? One of the challenges of delivering probiotics to your dog is that the probiotic bacteria must survive a trip through the highly acidic environment of the stomach. They must then be present in sufficient amounts to as to successfully colonize the intestines, and must be of a species that will actually benefit the dog. This means you must select a supplement with useful strains for dogs, with a high enough concentration (listed in CFUs, or Colony Forming Units) to be effective, and with an expiration date listed on the label to ensure you are using fresh product. Check with your veterinarian before beginning probiotic therapy if your dog is elderly, immune-compromised, or suffering from a severe bout of gastroenteritis or diarrhea.

Probiotics vs. Digestive Enzymes
Probiotics are different from digestive enzymes. Digestive enzymes are proteins that control the chemical reactions that break down food. These enzymes work to help the dog break down and digest proteins, fats, and any carbohydrates in the diet. Most enzyme products for dogs contain enzymes like amylase (for starches), lipase (for fats), protease (for proteins). Probiotics, on the other hand, are living organisms that do not help with breaking down large food molecules; they can, however, help with vitamin and mineral absorption. Digestive enzymes are typically recommended for dogs that are unable to digest their food well, even after a switch to a better and more digestible food. This includes dogs with issues like Exocrine Pancreatic Insufficiency or that have suffered from bloat in the past. These conditions are different from those normally treated with probiotics.