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19 JANUARY/FEBRUARY 2018 ● TVPJOURNAL.COM ESSENTIALS Low-fat Diets Low-fat diets typically have fat contents between 18-25 g/1000 kcal. Lower fat diets can be useful for reducing pancreatic stimulation and speeding movement through the stomach in vomiting animals. Low-fat diets are not appropriate for weight loss because they are not fortified with nutrients to offset low-calorie intake. Weight loss diets are also typically lower in fat than standard diets, but the fiber content and calorie density may not be appropriate for animals with poor appetites or vomiting. In addition, weight-loss diets usually are not restricted as low in fat as the gastrointestinal low-fat diets. Hypoallergenic Diets Diets designed to reduce symptoms of food allergies can be placed into 2 broad categories: novel protein or hydrolyzed. Novel protein diets use uncommon protein and carbohydrate ingredients to lessen the chance of exposure and a subsequent allergic response. In humans, most food allergens are glycoproteins that range in size from 14,000 to 40,000 Da. Proteins within range are large enough to activate B and T cells, but small enough to pass through mucosal membranes and interact with the immune system. Hydrolyzed proteins are low molecular weight peptides (<18,000 Da) with reduced antigenic potential because they are too small to bind with immunoglobulins. 1 As a result, they are less likely to elicit a response from the dog's immune system. Free amino acids are not allergenic but cannot be used due to their bitter taste and high osmolarity. There are many of hypoallergenic diets on the market. Novel protein diets are available over-the-counter (OTC) or by veterinary prescription. OTC tend to have a higher likelihood of contamination with common pet food proteins as compared to veterinary therapeutic diets. 2 SPECIFIC TYPES OF GASTROINTESTINAL DISEASE Vomiting Vomiting is the most common clinical sign of gastric disease. Dietary goals for vomiting are to minimize gastric irritation, promote gastric emptying, normalize motility and prevent gastroesophageal reflux. Fat and fiber delay gastric emptying, so choosing a lower fat, low-residue diet is usually ideal to manage vomiting and reflux. For acute, frequent vomiting food may be withheld for 24 hours. Small, frequent meals (3-6 per day) can also speed passage of food through the stomach. Small Intestinal Disease Acute small intestinal (SI) diarrhea with or without vomiting will often benefit from a low-residue diet. As normal digestion and absorption may be compromised. Small, frequent meals are recommending and early feeding for the intestines are best. Inflammatory bowel disease (IBD) is described as a group of chronic, idiopathic inflammatory disorders of the gastrointestinal tract. Severity can vary from mild- to life-threatening protein losing enteropathy (PLE). Clinical signs depend on section of bowel affected. Key nutrition factors for IBD include: ■ Avoid excessive dietary protein to minimize antigens that elicit an immune response (PLE is an exception and requires high protein) ■ Feed a low-residue diet as absorption may be impaired ■ Utilize a novel protein and/or hydrolyzed protein diets ■ Feed small, frequent meals Protein losing enteropathies such as lymphangiectasia require a low-fat diet. Long chain triglycerides, the most common form of dietary fat, stimulate lymph flow and increase protein leakage through the lymphatic vessels. Lymphangiectasia can be primary, but is often secondary to IBD. A low-fat, high-protein, low-residue diet is desired for these cases. Our nutrition practice usually assumes cases of lymphangiectasia are secondary to IBD unless proven otherwise, and also utilize hydrolyzed or novel protein diets for management. A low-fat, low-residue diet that is hypoallergenic and high protein is difficult to obtain. Our practice often utilizes Purina Feline HA for our canine patients as it meets most of these criteria. A portion of the fat from this diet comes from medium chain triglycerides (MCT) that passively diffuse from the GI tract to the portal system and partially bypass the lymphatic system. Thus, calorie density is maintained while lowering long chain fatty acids. Short Bowel Syndrome develops from massive resection of the small intestine and may result in malabsorption due to lack of surface area. Cobalamin deficiency may occur if ileum is resected. These cases benefit from low-residue diets. Moderate- to high-fat, energy-dense foods that are low to moderate in fiber are ideal. Supplementation of fat soluble vitamins and cobalamin may be needed and patients should be fed small, frequent meals.