Q:I know that I can buy probiotic supplements for my dog that are good for her gut, but I’ve also seen some dry dog food that contains probiotics. Will that do as much good for her GI system as the probiotics in pills?
Redland Hills, California
A: We need to back up a little to answer this question. First, even the evidence behind probiotic supplements is, at best, limited. They supposedly contain “good” bacteria to restore bacterial balance in an overactive or “sensitive” gut that’s prone to diarrhea and other GI problems, but they often don’t contain them, and even when they do, evidence for their efficacy is scant. There’s no evidence of benefit for general wellness, either. When J. Scott Weese, DVM, DVSc, DACVIM, an internationally renowned microbiology researcher at the Ontario Veterinary College in Canada’s University Guelph, analyzed 25 probiotics available in regular retail stores, 10 of them did not even list the bacterial counts in their merchandise. Of the 15 that did, only one in four actually contained what the label said. Some products mentioned that they contained bacteria that don’t exist; names were either made up or misspelled. Other problems included failure of the bacteria supposedly in the supplements to grow (they have to be alive and multiplying to do any good in a dog’s gut), bacterial counts that were too low to effect beneficial changes in the gut, and lack of an expiration date. In the end, only two products of the 25 met criteria Dr. Weese looked at for quality control.
The picture is even bleaker for quality control when it comes to probiotics — good bacteria — in dry kibble. A separate study by Dr. Weese and colleagues showed that none of 19 dry commercial pet foods claiming to contain probiotics actually had what was listed in the ingredients list of the food. (Probiotics can only be included in dry kibble because the heat involved in the canning process would kill them.) Granted, that study was conducted back in 2003. But while the inclusion of probiotics in pet foods has increased in popularity since then, there is no proof that the quality control has also increased. We advise against paying a premium price for “premium” dog foods marketed as containing probiotics.
None of this is to say that probiotics hold no promise for treating problems in the gastrointestinal tract. They do. The research so far indicates that certain probiotics may be able to ameliorate constipation, while others appear to cut down on stress-related diarrhea. The basic idea is that if you flood the gut with hundreds of millions of “good” bacteria in a probiotic supplement, they crowd out so-called bad ones or change the ratio of various microorganisms so that the large intestine has an easier time passing fecal waste through — not too slow, not too fast.
But the science lags behind the marketing. There are many studies about probiotics in people but hardly any well controlled research on dogs. And the research that does look positive is not astounding. Improvements in bowel function have been on the order of 10 to 30 percent. That’s significant, but it won’t necessarily look like a huge improvement to pet owners.
The bottom line: if your dog suffers from stress diarrhea or other acute forms of bowel difficulty (as opposed to having diarrhea because of an ongoing illness that needs to be treated medically), a probiotic supplement (but not kibble claiming to have probiotics) might be worth a try. But you really need to work with your veterinarian in choosing a brand, and in choosing the amount you give your dog over a specified period of time. Even with the vet’s help, it may not work, or it may only work a little bit. Probiotics are not miracle workers.