The Importance of Fiber in Cosmo's Canine Diet
As mentioned in previous posts, Cosmo requires a special diet due to his propensity to form calcium oxalate bladder stones. In addition, he developed hyperlipidemia last year which necessitated a low-fat diet. We started his low-oxalate, low-fat diet early in 2018 and two ingredients which were good sources of fiber (banana chips and pita chips as treats) were eliminated to reduce the fat content of his diet. This reduced the fiber content from about 4.5% (dry matter) to 3.8%. Then in September, I eliminated green peas from his diet thinking that it would improve an intestinal gas problem he was having. That bought the fiber content down to 2.8%.
Cosmo has a history of occasional bouts of diarrhea dating back to 2011. At that time the problem was diagnosed as being caused by an overgrowth of Clostridium bacteria in his gut. This is not an unusual condition in dogs and can be brought on by numerous factors including stress. It can usually be treated successfully with a few doses of the antibiotic metronidazole. In Cosmo's case, if he was not treated with metronidazole when mucous appeared in his soft stools, diarrhea would soon develop, and on occasion, vomiting. This problem was typically a yearly or semiannual event. However, since he has been on a diet with relatively low fiber the problem has been much more frequent as can be seen from this calendar which I started for our Arizona vet.
The problem came to a head in September just before we left for our annual trip from Anacortes, WA to our Arizona home. In addition to the stress he may have felt regarding our move, he also had impacted anal glands which prompted a visit to his Washington vet on September 15. Anal glands are naturally self-expressed during defecation but with the soft stools he was producing, this was not happening. When the glands become impacted they cause discomfort or even pain for the dog (i.e., more stress). After the vet expressed the glands, that problem was addressed, but he continued to have bouts of very soft stool. If the stool appeared to contain mucous, I treated with metronidazole until the problem passed.
After we arrived in Tucson in late September we took him to his Arizona vet (Dr. Joshua Fender) for another consultation. He reviewed his diet and noted that the fiber content for Cosmo should be at least 5% of dry matter (it was then 2.8%) and suggested adding Metamucil to his diet. I did that by adding 1/2 level teaspoonful to each of his twice-daily meals (about 1.7g per meal). The addition of the Metamucil and the reintroduction of green peas in his diet brought the total fiber to 5.1%. The increase in fiber had an immediate positive effect! The stools became much more formed and were solid enough to be picked up without leaving a residue. The amount of intestinal gas was also much reduced. Cosmo hates to "fart" and almost always turns around to see what just escaped from his anus. So it is easy to see when he has gas. I have tried larger amounts of Metamucil (up to 3/4 level teaspoonful per meal), but it does not seem to be more effective and makes his food too sticky. I add the Metamucil just before giving him the food (well mixed).
I may have caused some of his problems by not paying attention to the fiber level in his diet. Pet Diet Designer does not show fiber content on the main "balance screen" and only shows it on the Nutrient Report which I don't always review. So it was easy to lose track of the amount of fiber in his diet. I will check fiber from now on! But even if the amount of fiber was displayed more prominently I might not have thought to increase the fiber in his diet for loose stools. I think of fiber, such as Metamucil, as being a laxative! Also, many references I have seen online recommend 2.5 to 5% (DM) for the minimum amount of fiber in dog food. Most commercial dog food contains a fair amount of insoluble fiber in the form of plant-derived cellulose derivatives (e.g., beet pulp). I have yet to find many good sources of insoluble fiber since most contain oxalate or are high in fat. Both of these are contraindicated in Cosmo's diet. However, about 73% of the fiber in green peas is insoluble (reference). Metamucil is mainly soluble fiber which absorbs water and forms a gel in the gut. This might aid in the movement of food residue through the digestive tract. It is also possible that the soluble fiber in Metamucil is metabolized by gut bacteria to compounds such as short-chain fatty acids which alter the environment of the intestinal tract and this change somehow alters what is causing the soft stools/diarrhea (reference). Here is another good reference to this topic.
There is some research to indicate the Metamucil can be useful in treating diarrhea in dogs (reference here). And there is one anecdotal claim for its usefulness in treating soft stools in a dog. It was effective for at least three years.
Whatever the effect, the addition of Metamucil fiber to his diet seems to be helping Cosmo. So far he has had normal stools for 16 days without any metronidazole. I have also been giving him a dose of ForteFlora (probiotic) every three days. We have used this probiotic for years and although it has not prevented his loose stools it might encourage a more healthy flora in his gut while on Metamucil. Time will tell if the combination of Metamucil and ForteFlora solve this problem. Stay tuned.
Update 11/13/18: Cosmo has had normal stools for 27 days without metronidazole. Today he had his anal glands checked by our vet tech and they were empty. Great news. They must be secreting normally with each bowel movement. I am amazed at how a bit of fiber (about 1.7 grams of Metamucil twice daily) has seemed to solve his soft stool problem.