Diet for Hyperthyroidism in Cats

Some cats successfully manage their hyperthyroidism through diet.
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If Missy’s slimmed down lately, yet acting a bit cranky despite her svelte figure, it may be due to a hyperthyroid condition. Too much thyroid hormone can make cats irritable and lose weight. Hyperthyroidism is a serious condition, but it has several treatment options, including a change in diet.

Finding the Right Treatment

It can be difficult to find the treatment method that’s just right for you and your feline. Radioactive iodine may be too expensive. Missy may not be a good candidate for thyroid surgery. Or you’ve learned over time that pilling Missy is like a good old-fashioned wrestling match. One pet food company, Hills Pet Nutrition, has addressed those issues with a prescription diet designed specifically for hyperthyroid cats. The food has a low level of iodine to help normalize thyroid levels, but enough iodine to ensure Missy doesn't become iodine deficient. To date, there are no other manufacturers of hyperthyroid food.

Prescription Food

The food has been a successful alternative for many people, but before you celebrate finding the perfect solution, there are a few things to keep in mind. Missy won’t be able to eat anything but this diet for the rest of her life – which could be a long time because hyperthyroidism, though serious, is highly treatable. That means no special treats or snacks. If she eats something else, the diet won’t work because the iodine level will be too high, negating the benefit of the prescription food. Also, if she's got sisters or brothers, they can't eat this food unless they have the same condition because it won't meet their dietary requirements.

Other Diet Considerations

Some people prefer to manage their cat's health in a more holistic manner, which often means limiting medications and many commercial foods. This approach requires a lot of research and diligence. In his blog, veterinarian Dr. Mark Peterson recommends feeding most hyperthyroid cats “close to what they would be getting in the wild. That would be a diet composed of approximately 50-60% protein, 5-10% carbohydrates, and 30-50% fat." Dr. Peterson notes that older cats -- the age group most impacted by hyperthyroidism -- tend to lose muscle mass as they age. Limiting cats' protein intake as they age is counterintuitive because they need the protein to help maintain their muscle mass. According to Dr. Peterson, potential diet-related risk factors for hyperthyroidism also include certain varieties of canned cat food (fish, liver and giblets), too much or little iodine in the diet, high levels of selenium in the diet, cat food cans with plastic linings (that may release risky chemicals), and soy isoflavones in commercial food that may interfere with thyroid function.

Making a Decision

It’s tempting to use food to control Missy's hyperthyroidism. After all, the expense won't be much different, as you’d be buying her cat food anyway. However, there is the possibility that she won't tolerate the food or that it's too difficult to manage separate feeding if she shares her home with other cats. If you decide to try to manage her condition with diet and are interested in other options, it's important to do plenty of research and keep your vet informed of what you're doing. Missy will need to have her thyroid level tested regularly to ensure the treatment you decide on is working.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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