Drugs are often given inappropriate precedence in the treatment of gastrointestinal tract diseases. Diet has a marked influence on gastrointestinal tract function and the manipulation of dietary composition provides clinicians with a powerful therapeutic tool. During acute gastroenteritis, a short period of fasting is recommended. ‘Feeding through’ diarrhoea (without a period of fasting) is recommended in human infants but has limited applicability in dogs and cats, primarily because different types of diarrhoea are commonly treated by veterinary surgeons compared to physicians. Following the fast, a change from the animal's regular food to a diet containing novel protein sources is advisable. This minimises the likelihood of acquired food allergies to staple proteins. Allergy avoidance may require special techniques such as rotation diets or protein hydrolysates. Dietary fat is usually kept to a minimum during gastrointestinal dysfunction as malabsorbed fatty acids and bile acids promote secretory diarrhoea in the large bowel. Recommendations to feed high fat rather than high carbohydrate diets to cats with diarrhoea need to be objectively examined. The type of fat fed may also prove to be an important consideration. Incorporation of omega‐3 fatty acids into the diet has been shown to have anti‐inflammatory effects on the gastrointestinal mucosa. In diseases of the small bowel, it is traditional to use low fibre diets. This recommendation needs re‐examination because the binding and gelling properties of fibre are of potential benefit in the treatment of small bowel diarrhoea. High fibre diets are useful in most large bowel diseases. Soluble (fermentable) fibres (eg, psyllium, oat bran and fibrim) rather than insoluble (non‐fermentable) fibres (eg, wheat bran) give better results in treating colitis. The benefits from soluble fibre probably relates to the binding of irritant bile acids and the generation of volatile fatty acids, such as butyrate, that nourish the colonic epithelium and encourage growth of normal bacterial flora.
New ideas for the dietary management of gastrointestinal tract disease