Although viewed mostly as an annoyance and diet or breed related, flatulence may also be an indication of a medical condition. Diseases that affect intestinal motility, intestinal digestion and malabsorption, and food hypersensitivity can increase flatulence. Understanding intestinal gas production, intestinal motility, and intestinal bacterial populations offer more opportunities for interventions to reduce gas production and flatulence for the benefit of both the dog and owner.
Causes of Flatulence in Dogs
Gas in the intestine is a result of ingestion or production within the gut. Although swallowing air, or aerophagia, does occur in animals that “inhale” their meals or have respiratory conditions, most intestinal gas is produced in the intestine. When the acidic "chyme" (stomach contents) is introduced to the alkaline environment of the small intestine, water and carbon dioxide (CO2) are produced. Although most of this CO2 diffuses into the vascular system, some is left within the intestines. The remainder of intestinal gas production is from lower intestinal and colonic bacterial production.
Gas that is not eliminated immediately causes intestinal retention that results in "growling sounds," or borborygmus. Non-eliminated gas accumulation can cause intestinal discomfort and discomfort that may be hard for veterinarians to identify.
The malodor associated with flatulence is caused by certain classes of intestinal bacteria that reduce sulfur in amino acids, certain vegetables and nuts, and sulfated complex sugars used for gelling.
Fiber tends to slow gas movement in the intestine and increase gas production, especially the highly purified fermentable fibers like psyllium and pectin. Less digestible fiber like cellulose and corn bran are less flatulogenic. Changes in fiber content and type require 2-5 days of dietary adaptation.
Research in humans and other animals suggests that foods high in fat decrease intestinal transit of gas, and increase borborygmus and flatulence.
Management of Flatulence in Dogs
Although the relative terms "high" and "low" are difficult to define, diets that contain highly digestible protein and carbohydrates with low quantities of fat are preferred for the avoidance of flatulence. Reducing the fermentable fiber sources like gums, carrageenan, and pectins also may decrease flatulence. This is often difficult with commercial diets. Diets containing broccoli, cabbage, cauliflower, Brussels sprouts and other cruciferous vegetables should be avoided when feeding the flatulent pet.
Homemade diets of a 50:50 mixture of 1% cottage cheese and white rice by weight has proved useful to reduce flatulence and allow dietary experimentation to identify the cause of the problem. A 25:100 mixture of broiled or boiled chicken breast and white rice is a possible alternative. My experience favors the cottage cheese and rice diet. Keep in mind that these diets are nutritionally inadequate and are to be used only on a short term basis to confirm that food is the source of the flatulence rather than a more involved medical condition.
Some veterinarians prefer the hydrolyzed, or "short protein chain" foods to homemade alternatives. Theoretically, these should be effective, but I have found them to be inferior with little relief of symptoms prompting their use.
Research in humans and dogs suggest that exercise reduces flatulence. The timing of exercise to feeding has not been studied, so recommendations along these lines is lacking. Increasing the amount of exercise is the present suggestion.
Frequent, smaller meals have been advocated, but the research suggests that this is subject to significant individual variability. Pets that fail to respond to these management strategies should be evaluated for more significant intestinal dysfunctional conditions.
My clients that have use Beano and other human products at my suggestion report a significant decrease in flatulence but this evidence is anecdotal and not substantiated by peer reviewed research.
Dr. Ken Tudor
Image: Peaches, by Vivian Chen / via Flickr