Hot Literature: Cats, fats, and chronic diarrhea
For dogs with diarrhea, fat-restricted diets have long been suggested, largely because the digestion and absorption of fats are much more complex than for other nutrients. As a result, fat malabsorption or maldigestion can develop in response to many different conditions, and fermentation of undigested fats in the colon can lead to secretory diarrhea and intestinal inflammation.
However, diets high in fat have been recently suggested for cats with diarrhea, largely because more calories in smaller volumes of food can be achieved. The effects of either a fat-restricted or high-fat diet on chronic diarrhea in cats have not been well-studied. But recently published research seeks to begin an investigation into the role of dietary fat in chronic diarrhea in cats.
The cats were randomly assigned to one of two groups for a six-week period. The cats were fed either a high-fat (20% dry basis) or a low-fat (10% dry basis) diet for the duration of the study. Both experimental diets used the same ingredients (adjusted only for fat content) and were formulated to be highly digestible and provide complete nutrition. Owners were unaware of which diet their cats were receiving. The owners agreed to feed only the assigned diet, give no medications, and keep a daily journal recording a fecal score (from watery to firm or dry feces on a 0-100 scale) for each defecation. The daily fecal scores for an entire week were then averaged, and the averages for weeks 1, 3, and 6 were used to evaluate the response.
While subtle, an association was also seen between low serum B12 concentrations and fecal scores. The response to the diets was poorer for cats with B12 concentrations below the reference range at baseline, and the degree of improvement was also less. Serum B12 concentrations were not reevaluated at any time, so, as the authors of this study note, it is not known whether the deficiency improved along with the fecal scores or whether these cats would have had a more significant response to the diets had their low B12 concentrations been corrected.
Finally, no definitive diagnosis was made for any of the study participants, so it is not known whether the nonresponders had different causes of their chronic diarrhea than those that had improvement. Based on this new data, dietary change for cats with chronic diarrhea appears to be beneficial and should be considered when treating these cases, but the fat content of the diet seems to be unimportant.
Laflamme DP, Xu H, Long GM. Effects of diets differing in fat content on chronic diarrhea in cats. J Vet Intern Med 2011;25(2):230-235.
Link to abstract: http://onlinelibrary.wiley.com/doi/10.1111/j.1939-1676.2010.0665.x/full