Resumen de Total dietary fiber composition of diets used for management of obesity and diabetes mellitus in cats
Objective—To determine total dietary fiber (TDF) composition of feline diets used for management of obesity and diabetes mellitus.
Design—Cross-sectional survey.
Sample—Dry veterinary (n = 10), canned veterinary (12), and canned over-the-counter (3) feline diets.
Procedures—Percentage of TDF as insoluble dietary fiber (IDF), high-molecular-weight soluble dietary fiber (HMWSDF), and low-molecular-weight soluble dietary fiber (LMWSDF) was determined.
Results—Median measured TDF concentration was greater than reported maximum crude fiber content in dry and canned diets. Median TDF (dry-matter) concentration in dry and canned diets was 12.2% (range, 8.11% to 27.16%) and 13.8% (range, 4.7% to 27.9%), respectively. Dry and canned diets, and diets with and without a source of oligosaccharides in the ingredient list, were not different in energy density or concentrations of TDF, IDF, HMWSDF, or LMWSDF. Similarly, loaf-type (n = 11) and gravy-type (4) canned diets differed only in LMWSDF concentration. Disparities in TDF concentrations among products existed despite a lack of differences among groups. Limited differences in TDF concentration and dietary fiber composition were detected when diets were compared on the basis of carbohydrate concentration. Diets labeled for management of obesity were higher in TDF concentration and lower in energy density than diets for management of diabetes mellitus.
Conclusions and Clinical Relevance—Diets provided a range of TDF concentrations with variable concentrations of IDF, HMWSDF, and LMWSDF. Crude fiber concentration was not a reliable indicator of TDF concentration or dietary fiber composition. Because carbohydrate content is calculated as a difference, results suggested that use of crude fiber content would cause overestimation of both carbohydrate and energy content of diets.
Obesity is prevalent among the domestic feline population1 and is associated with a 4-fold risk of developing diabetes mellitus.2 Obesity likely plays a primary role in insulin resistance in cats, and glucose intolerance with impaired insulin secretion is associated with weight gain.3 The addition of fiber is a common strategy used in obesity management because cats regulate food intake by volume.4 Diets high in water or fiber reduce both energy density and calorie intake4–6 and may be useful in prevention and treatment of both obesity and diabetes mellitus.
Although some studies7–10 suggest that diets with low carbohydrate content and high protein content may be advantageous in managing feline diabetes mellitus, the fiber types and concentrations of the diets in those studies were not well characterized. Other diets intended to manage feline obesity or diabetes mellitus highlight an increased fiber content in their product guides or marketing materials; however, direct comparison among diets is not possible because TDF (composed of IDF, HMWSDF, and LMWSDF) information is often not provided. Quantification of fiber fractions is valuable, given that the effects of fiber types are not uniform. Fiber supplementation, particularly IDF, may affect nutrient absorption and modulation of postprandial glycemic response,11 whereas short-chain fatty acid production from bacterial fermentation of SDF (eg, inulin and fructooligosaccharides) supports beneficial colonic microbial populations,12–15 which are recognized as having a role in controlling obesity.16 Crude fiber, a required component of the GA of a pet food label, remains the only representation of fiber for most cat foods. The method for CF analysis, developed in 1806, recovers variable fractions of cellulose, hemicellulose, and lignin,17,18 which provides incomplete information on IDF content only. Crude fiber is a poor reflection of TDF, which can vary greatly among diets.17,19 However, traditional laboratory analysis of TDF also has limitations, given that the most commonly used methodology does not detect or quantify LMWSDF (oligosaccharides and most types of resistant starch). Until recently, there was not a practical method to quantify LMWSDF in addition to the IDF and HMWSDF typically measured and reported as TDF. Newer methodology has been recently developed,20,21 but further validation is needed, and widespread use has not yet occurred. As such, reported TDF concentrations may be underestimated depending on the method of measurement used.22 The objective of the study reported here was to determine TDF content as IDF, HMWSDF, and LMWSDF in veterinary therapeutic feline diets labeled for obesity and diabetes mellitus as well as a limited number of OTC canned diets occasionally recommended for feline diabetes mellitus, by means of an updated method of measuring TDF. We hypothesized that measured TDF would be greater than reported maximum CF, that TDF and LMWSDF would be greater in dry diets than in canned diets, and that LMWSDF concentrations would be greater in diets with added oligosaccharides, compared with those without. We further hypothesized that TDF concentration would be lower in low-carbohydrate diets versus other diets and higher in diets primarily recommended for obesity versus those primarily used for diabetes mellitus.
