Disease Management: Nutritional
Changes to nutrition may be useful in the management of disease for the senior dog or cat and have been used for conditions such as hyperthyroidism, chronic kidney disease, osteoarthritis, and diabetes mellitus. Different ingredients in a balanced diet may be used to treat or manage a chronic disease; for example, adding antioxidants to the diet of dogs and cats may help manage conditions such as cognitive dysfunction syndrome, immunosenescence, osteoarthritis, and heart disease.58–60 Long-chain omega-3 polyunsaturated fatty acids have been shown to have synovial anti-inflammatory effects in osteoarthritis,61–64 and medium-chain triglycerides have been recommended for cognitive dysfunction syndrome.65 For cats with diabetes mellitus, treating for issues such as obesity and inactivity is known to be beneficial to managing the disease. A dietary change to a high-protein (>45% on dry-weight basis) and low-carbohydrate (<15%) diet given in small frequent meals may help minimize postprandial glucose influx.66
For patients with renal disease, studies have shown that a renal diet with restrictive protein provides longer survival times with fewer uremic crises for patients.67 IRIS currently recommends phosphorus control with a reduction in intake and addition of binders.68 At IRIS stage 2, the addition of long-chain omega-3 polyunsaturated fatty acids is suggested. Healthy pets and early renal cases should not require protein restriction, and quality and quantity should be carefully managed in later IRIS stages. Protein restriction is to be considered at IRIS stage 2 and recommended at IRIS stage 3.
For cats with hyperthyroidism, clinical concerns include weight loss and LBM loss, and a high-protein (>40%), limited-carbohydrate (<25%) diet while restricting iodine is recommended.66,69 Fish-based diets should be avoided. Dogs that have developed hypothyroidism may require a diet that has restricted calories.
Palliative care patients may be hyporexic or anorexic. Focus may need to be shifted from a balanced diet to just getting the animal to eat something. For palliative patients that are anorexic, enteral or parenteral feeding (e.g., esophagostomy or percutaneous endoscopic gastrostomy tubes to reduce food aversion) should be discussed with the client. Feeding tubes can also be beneficial for giving parenteral medication, the amount of which may be substantial in the end-of-life patient. Appetite stimulants, medication for nausea and vomiting, and careful fluid administration should be provided for hyporexic or anorexic patients.70 Resumption of favorite foods, even if not medically balanced, may provide some nutrition with a more positive experience for both the caregiver and patient.