Diet for Your Pet with Cushing’s Syndrome

As with humans, the health and wellbeing of your pet largely depend on two main factors--diet and exercise. This is even more the case with pets suffering from Cushing’s syndrome.Cushing's syndrome may result from any of several causes affecting the adrenal glands, the pituitary gland (hypophysis), or the hypothalamus that result in abnormally high levels of cortisol and/or other adrenal hormones.

In addition to medical treatment, which may include pharmaceuticals either alone or in combination with lignans and melatonin, careful attention must be paid to diet and exercise.  Chronically high cortisol levels promote high levels of blood glucose and, eventually, insulin resistance.  Accordingly, in addition to addressing high steroid hormone levels, the Cushing’s diet should contain a minimum of sugars and other non-structural carbohydrates.  Body weight should also be managed to keep it as close to your pet’s ideal body weight as possible. 

Feeding guideline

Any change in diet or exercise should be discussed with your pet’s veterinarian.  The first step in formulating a diet for your pet is to determine the number of calories needed to achieve ideal body weight, based on your pet’s age, breed and body condition score.  You can obtain rough calculations of your pet’s ideal body weight here and your pet’s suggested daily caloric intake at vetcalculator.  Keep in mind these are very rough calculations that can be used as starting points, but may need to be refined based on your pet’s response to an increase or decrease in total calories and based on your veterinarian’s advice. 

After determining the desired total daily calorie requirement, the second step is to determine the specific nutrients to achieve that calorie goal.  The specific balance of nutrients should respond to the specific excesses, deficiencies and needs of Cushing’s animals.  The key underlying defining features of a Cushing’s pet are increased blood corticosteroid levels and increased saturated fat levels.  Thus, a Cushing’s-specific diet must respond to those characteristics and limit fat intake generally and saturated fats specifically.

Nutritional therapy should continue alongside (and not in lieu of) medicinal therapy and appropriate dietary supplementation. Together, these therapies will help relieve the signs of Cushing’s syndrome by reducing the building blocks necessary for producing cortisol and other corticosteroid hormone levels.  Over time, lower circulating corticosteroid levels will reduce or eliminate disease signs.

Let’s talk specifics--What should I feed or avoid?

First, you should make sure your pet does not eat treats or scraps from the kitchen that are high in fat or sugar.  Feeding treats and scraps also throws off the diet you formulate unless the calories and nutrients are taken into account and offsetting reductions are made elsewhere in the diet.

Once you and your vet have determined an appropriate daily calorie intake, you need to determine the relative amounts of protein, fats, sugars and other carbohydrates and fiber.  The starting point for this can be the diet pre-formulated by the American Association of Feed Control Officers (AAFCO) specifically for maintenance for adult dogs or cats (and, for example, not that for growth or reproduction, which will invariably be too high in fats and carbohydrates).  If you feed a pre-formulated diet, you can look for those words (“adult” and “maintenance diet”) in the “AAFCO Statement” on the label in the “Pet Nutrition Facts” or “Guaranteed Analysis” panel, and then use the further information below to select among the options available.  Those who do not use a pre-formulated diet may align the nutritional contents of their diets with those of the AAFCO diet, and improving on it with the suggestions below.

The AAFCO diet only sets minimum and, sometimes, maximum thresholds for different nutrients.  Thus, there can still be a great range in the nutritional therapeutic benefits of different brands and of different lines within brands.  In selecting among your many options, preference should be given to those that are lower in fats, lower in carbohydrates (especially sugars or other non-structural carbohydrates), higher in protein and contain moderate (5-17%) amounts of fiber.

·      LOW IN FAT

As mentioned, dogs suffering from Cushing's disease have high adrenal steroid levels (including cortisol).  All such steroids are made from cholesterol and its various metabolites.  Thus, a low cholesterol diet can limit the body’s synthesis of cortisol and other steroids. The AAFCO recommended diet limits fat content (based on dry matter (DM)) to 12% or less.  Unfortunately, AAFCO doesn’t differentiate among saturated vs unsaturated fats and doesn’t specify a cholesterol level.  Thus, if you are self-formulating, you can improve on the AAFCO recommendations by selecting fats that are unsaturated or low in cholesterol and/or by further reducing total fat content.  If you are using a pre-formulated diet, you can use the same criteria to select among the available products based on the listed ingredients and reported fat content in the “Guaranteed Analysis” portion of the product label.

·      MODERATE FIBER

Fiber will aid in digestion and bowel movements as well as feed and populate the microbiome in the pet’s gut.  (A healthy microbiome is critical for fending off a range of diseases and is essential if your veterinarian has prescribed lignans and melatonin to treat your pet’s Cushing’s syndrome.)  In addition, soluble fiber can reduce cholesterol levels.  Thus, fiber contents should be moderate to meet the body's needs. Based on DM, the crude fiber should be 5-17%.

·      HIGHLY-DIGESTIBLE PROTEINS

Compared to normal diets, the digestible protein content in the dog’s diet should be high. Highly-digestible protein sources are muscle meat, organ meat, and egg whites. Increasing any of these proteins would make the diet suitable for dogs suffering from Cushing's disease. However, plant-based proteins have low digestibility (of 54-75%) and, thus, should be limited or avoided altogether.

·      LOW SODIUM LEVELS

Cortisol increases both heart rate and blood pressure.  Thus, dogs suffering from Cushing's disease often also suffer from hypertension.  As with humans, a low sodium diet can help keep blood pressure in the normal range.

·      ANTI-OXIDANTS

Chronically high cortisol levels are associated with increased levels of oxidative stress.  Thus, preference should be given to ingredients high in anti-oxidants.

·      SUPPLEMENTATION

Supplementation in diet will help alleviate the adverse effects of Cushing’s disease. Thus, among others, your veterinarian may advise adding:

• Milk thistle or SAMe for liver support;
• Additional antioxidants such as beta-carotene, alpha-tocopherol, methionine, selenium, and vitamin C;
• Omega-3 fatty acids to reduce triglycerides and fat levels in the blood;
• Lignans and melatonin

When to feed

The recommended meal frequency is two times a day for an exercising dog. The number of meals must not exceed the daily requirement of your dog. It may vary from dog to dog and condition to condition, and should be determined in consultation with your veterinarian.

Feeding and exercise are interlinked for the health and wellbeing of your dog or cat.  Studies show that your dog’s performance will be reduced if exercised too soon after being fed or if fed too close to sleep.  To the extent practical, your dog should be fed 6-8 hours before exercise.

Dogs perform best when they use the energy of previously fed meals. They may use carbohydrates, proteins, and fats stored from the previous meal.  Exercise is essential for Cushing’s dogs and a great antidote for treating insulin-related conditions.  We will cover exercise recommendations in a future article.