Diet for Cats With Hyperthyroidism

Hyperthyroidism (overactive thyroid gland) can result in serious complications if left untreated. In this post, our Springfield vets share the ideal diet for cats with hyperthyroidism and what to avoid.

Feline Hyperthyroidism

Located in the neck, your cat's thyroid glands produce many hormones that help regulate several processes throughout the body and control your cat's metabolic rate. If 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 can most often be blamed on a non-cancerous tumor located somewhere on the thyroid gland. However, in some rare cases, the tumor may develop into thyroid cancer. 

If your cat suffers from hyperthyroidism, their metabolism will speed up. This means your kitty will tend to burn energy too quickly, resulting in weight loss even if they are eating significantly more food than usual.

Signs of Hyperthyroidism in Cats

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

Symptoms of hyperthyroidism in cats are often subtle in the early days. However, they gradually become more severe over time. Other underlying health issues may also mask or complicate symptoms of hyperthyroidism, so it's important to see your veterinarian early if your cat shows any symptoms listed below. Cats producing too much thyroid hormone may show one or more of the following symptoms:

In its more advanced stages, the condition often causes cats to pant when they are stressed, which is unusual for cats. While many cats suffering from hyperthyroidism have a good appetite and appear restless, others may feel lethargic or weak or experience a loss of appetite. Left untreated, potential long-term complications of hyperthyroidism include high blood pressure (which is linked to damage to the eyes, heart, brain, and kidneys) and heart failure. 

If you or your regular vet have noticed any of the above symptoms in your cat, you might consider using your favorite search engine to search for 'internal medicine veterinarian near Springfield' to find reputable and experienced specialists, including our team at The Regional Veterinary Referral Center. 

Diagnosing Feline Hyperthyroidism 

It can be somewhat tricky for vets to diagnose hyperthyroidism in older cats. Your kitty will need 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. 

Diets for Cats With Hyperthyroidism

Hyperthyroidism in cats can often be managed through an iodine-restricted prescription diet from your vet. This may be recommended in conjunction with other treatment options, such as surgery to remove the thyroid or antithyroid medication.

Iodine intake is necessary for the production of thyroid hormones, so the goal of an iodine-restricted therapeutic diet is to help reduce the production of thyroid hormones by reducing iodine in your cat's diet.

A hyperthyroidism diet for cats should focus on iodine levels limited to 0.32 parts per million or less. Your vet may prescribe high-quality canned or dry cat food specially made for cats with hyperthyroidism.

Strict adherence to the low-iodine diet is necessary for this treatment to be effective, which can prove challenging for some pet parents and their cats. Along with feeding your cat prescription food, you will need to avoid giving your cat treats and people food and prevent your cat from hunting for their own meal while outside. If your cat eats any food other than your prescribed diet, this could sabotage the careful balance of iodine necessary to improve hormone levels. 

Dietary Treatment Plans

If a diet plan is one component of your cat's treatment, he or she may benefit from eating grain-free food high in energy and protein, which can help your cat regain weight, and muscle mass lost due to their overactive thyroid. Your vet may prescribe specific brands of food depending on your cat's needs. 

Conversely, if your cat's kidney function has been compromised, more moderate protein levels may be required. For cats with kidney disease, eating too much protein can worsen their symptoms. 

The high water content in canned food makes it an ideal choice, as this can counterbalance your cat's tendency to produce too much urine due to high thyroid hormone levels. It's also important that your cat has free access to clean water at all times. 

Some studies show that after three weeks of following a prescription hyperthyroidism diet, levels of T4 thyroid hormones begin to decrease. Within a few months, they may even return to normal levels.

Once your cat's thyroid levels have been normalized with methimazole, thyroidectomy, or radioactive iodine therapy, and the cat has regained a healthy amount of weight, their diet plan can be adjusted to meet their needs.

Our internal medicine specialist is here to work with you and your primary veterinarian. We can answer your questions, address concerns, and offer advice for your pet's needs (including food and dietary requirements) at every stage of illness and recovery. We recommend discussing any changes to your cat's diet with your vet first before implementing them.

Tips for Choosing the Right Cat Food for Hyperthyroidism

When it comes to a hyperthyroid diet for cats, there are a few tips to help keep your furry friend on the mend, including:

Do feed your cat:

• Canned or raw diets that contain little to no fruits, vegetables, or grains. Any canned cat food is better than any dry, which contains too much carbohydrate and plant-based protein.
• Meat by-products are fine for carnivores: they’re simply protein sources such as organ meats and entrails that people don’t find appetizing. 
• Pate-style foods. Gravy-based foods tend to be high in carbs.

It may be best to avoid:

• Soy-containing foods.
• BPA (Bisphenol A) in canned food linings.
• Fish and fish by-products.
• Plastic food and water bowls (use glass, ceramic or metal instead).
• Storing food in plastic containers.
• Ultra-high or ultra-low iodine diets.

Important: If your cat is being fed a prescription iodine-restricted diet specifically for hyperthyroidism, they cannot be fed any other foods. This includes all types of treats, snacks and human foods.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.