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Diet for Cats with Hyperthyroidism

Learn how changes to your cat's diet can help prevent serious health issues caused by hyperthyroidism. Our Los Angeles vets explain how.

What is hyperthyroidism in cats?

Your cat's thyroid glands, located in the neck, produce numerous hormones that regulate various processes throughout the body and control their metabolic rate. In case the thyroid produces too much or too little of these hormones, symptoms of either hypothyroidism (low levels of hormone) or hyperthyroidism (too much hormone) will appear.

Hyperthyroidism is usually caused by a non-cancerous tumor in the thyroid gland. However, in some rare cases, the tumor may develop into thyroid cancer. If your cat is suffering from hyperthyroidism, their metabolism will speed up, causing your kitty to burn energy too quickly, which may result in weight loss even if they are eating significantly more food than usual.

What are the symptoms of hyperthyroidism in cats?

While cats of any breed can experience hyperthyroidism, most cats diagnosed with the condition are older—typically between 12 and 13 years old. The disease equally impacts male and female cats. 

The symptoms of hyperthyroidism in cats can be difficult to spot in the early stages, but they tend to worsen gradually over time. Additionally, other underlying health problems may mask or complicate hyperthyroidism symptoms, so it's crucial to take your cat to the vet as soon as possible if you notice any of the following symptoms. Cats with an overactive thyroid gland may exhibit one or more of the following symptoms:

  • Low tolerance for heat
  • Increase in thirst
  • Hearty or increased appetite 
  • Increase in heart rate 
  • Irritability 
  • Poor grooming habits 
  • Restlessness
  • Mild diarrhea and vomiting

When cats suffer from hyperthyroidism, they may pant when stressed, which is unusual for them. Although some cats with this condition may have a good appetite and appear restless, others may feel lethargic or weak and lose their appetite. If not treated, hyperthyroidism may lead to long-term complications such as high blood pressure, which is linked to damage to the eyes, heart, brain, and kidneys, as well as heart failure.

If you or your regular vet notice any of these symptoms in your cat, you may want to search for "internal medicine veterinarian near Los Angeles" on your preferred search engine to find reputable and experienced specialists, including our team at Ambassador Dog & Cat Hospital.

How is hyperthyroidism diagnosed? 

It can be somewhat tricky for vets to diagnose hyperthyroidism in older cats. Your kitty will need to have a physical exam, during which your vet will palpate your cat's neck area to look for symptoms of an enlarged thyroid gland. Our veterinary internal medicine specialists use state-of-the-art diagnostic testing to help diagnose your pet's condition and provide advanced care to manage this disease. 

What is the best diet for cats with hyperthyroidism?

Hyperthyroidism is a condition that can affect cats, but it can be managed through an iodine-restricted prescription diet from your veterinarian. This treatment may be used together with other options like surgery to remove the thyroid or antithyroid medication.

Iodine is required for the production of thyroid hormones. Therefore, the iodine-restricted therapeutic diet aims to reduce the production of thyroid hormones by decreasing iodine in your cat's diet. To ensure effectiveness, the iodine levels in foods for cats with hyperthyroidism should be limited to 0.32 parts per million or less. Your veterinarian may prescribe high-quality canned or dry cat foods specially made for cats with hyperthyroidism.

It's important to stick to the low-iodine diet strictly for the treatment to be effective. However, this can be challenging for pet owners and their cats. Along with feeding your cat a prescription food, you will need to avoid giving your cat treats and people food and prevent your cat from hunting for their own meal outside. If your cat eats anything other than the prescribed diet, it could upset the careful balance of iodine necessary to improve hormone levels.

Diets for Cats with Hyperthyroidism as Part of a Treatment Plan

If your cat is being treated for hyperthyroidism, their diet can play a vital role in their recovery. For example, if your cat needs to regain weight and muscle mass lost due to hyperthyroidism, a grain-free food high in energy and protein may help. Your vet may recommend specific brands of food based on your cat's needs. However, if your cat's kidney function is compromised, a diet with moderate protein levels may be required, as too much protein can worsen the symptoms of kidney disease.

Canned food with high water content is ideal for hyperthyroid cats as it helps counterbalance their tendency to produce excessive urine due to high thyroid hormone levels. It's also essential to ensure your cat has access to clean drinking water at all times.

Studies show that following a prescription hyperthyroidism diet for three weeks can decrease T4 thyroid hormone levels, which may return to normal levels within a few months. Once your cat's thyroid levels have been normalized through methimazole, thyroidectomy, or radioactive iodine therapy, their diet plan can be adjusted to meet their needs.

Our internal medicine specialists are available to work with you and your primary veterinarian, providing advice on food and dietary requirements at each stage of illness and recovery. It's best to discuss any changes to your cat's diet with your vet before implementing them.

What is the prognosis for cats with hyperthyroidism?

If the condition is diagnosed and treated early, the prognosis for cats suffering from hyperthyroidism is generally good. In some cases where the condition has become more advanced, complications with other organs can worsen the prognosis.

If your cat is suffering from hyperthyroidism, our veterinary internal medicine specialists can help. Contact our vets in Los Angeles to book an appointment for your pet.

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