Hyperthyroidism is a serious condition that negatively impacts a cat’s health. Unfortunately, it is the most common endocrine disorder in older cats and has been known to occur in about 10% of cats that are 10 years or older. The more common signs are an increase in thirst, urination, and appetite, as well as weight loss.
If you know that your cat has hyperthyroidism, you probably have already seen your vet to have this disease properly treated. Treatment usually includes an adjustment to your cat’s diet, medication, radioactive iodine therapy, or surgery. The most important part of a diet for a cat with hyperthyroidism is food that is low in iodine. Restricting iodine in a cat’s diet will help reduce the thyroid from overproducing the thyroid hormone, thyroxine, which causes hyperthyroidism.
The following reviews include dietary treatment products with little to no iodine that can be fed exclusively to your cat. We also include some high-protein options that might benefit a cat after radioactive therapy treatment if it is not diagnosed with kidney disease.
Important: Your veterinarian’s advice is essential, especially if your cat has a medical condition. Never change the diet of your cat suffering from hyperthyroidism, without your veterinarian’s authorization.
Disclaimer: The foods reviewed here were chosen because they have certain characteristics that might help with some of the causes or consequences of this medical condition. However, they are not a medical treatment or a substitute for medical treatment. Keep in mind that each medical case is different and what works for some pets may not work for others. Your veterinarian is the right person to advise you on the best diet for your pet’s case.
A Quick Comparison of Our Favorites in 2024
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Best Overall
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Hill’s Prescription Diet Thyroid Care Cat Food |
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Best Value
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Hill’s Prescription Diet Thyroid Care Dry Cat Food |
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Wellness Complete Health Cat Food |
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Instinct Original Grain-Free Cat Food |
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Instinct Limited Ingredient Cat Food |
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The 6 Best Cat Foods for Hyperthyroidism
1. Hill’s Prescription Diet y/d Thyroid Care Cat Food – Best Overall
| Flavor: | Chicken |
| Food texture: | Pâté |
| Protein: | 8% |
| Size: | 5.5 oz. x 24 |
The best overall canned food for hyperthyroid cats is Hill’s Prescription Diet y/d Thyroid Care Cat Food. This is the only canned food made specifically to help cats with hyperthyroidism, and it is available in a case of 24 cans that are 5.5 ounces each. It has been clinically proven that this Thyroid Care food will restore thyroid health in as little as 3 weeks. Since thyroid issues usually happen to older cats, kidney damage is another concern, and this food is also low in phosphorus and sodium, which will help with kidney health. It contains omega-3 and -6 for healthy skin and coat and added taurine and carnitine for a healthy heart and weight.
On the downside, it is expensive, and it contains pork by-products and corn flour. You’ll also need a vet prescription for this cat food.
2. Hill’s Prescription Diet y/d Thyroid Care Cat Food — Best Value
| Flavor: | Chicken |
| Food texture: | Dry |
| Protein: | 30% |
| Size: | 4 and 8.5 lbs. |
Our pick for best value dietary treatment for cats with hyperthyroidism is Hill’s Prescription Diet y/d Thyroid Care Cat Food. This dry food is explicitly designed to help cats with hyperthyroidism and is proven to improve thyroid health in three weeks. It decreases the T4 hormone production and helps support urinary, heart, and kidney health. It also aids in a healthy immune system and a healthy coat and skin.
However, it is still quite expensive, and the ingredients aren’t the greatest. In fact, corn gluten meal is listed as the first and, therefore, the main ingredient, which is strange, to say the least. But the food works.
3. Wellness Complete Health Canned Cat Food
| Flavor: | Chicken |
| Food texture: | Pâté |
| Protein: | 10.5% |
| Size: | 3 oz. x 24, 5.5 oz. x 24, 12.5 oz. x 12 |
Another great choice for food for cats with hyperthyroidism is Wellness Complete Health Cat Food. Now, this food isn’t super cheap, but when you have a cat with such a serious health condition, you do need to pay more to keep them in optimal health. This pâté is available in three different-sized cans and is grain-free, with chicken as the main ingredient. It’s full of omegas and antioxidants for immune system support and healthy skin and coat.
On the downside, some cats might not want to eat it (we know how picky felines are!), and on occasion, the food has a thicker and drier texture that some cats might also find off-putting.
4. Instinct Original Grain-Free Pate Canned Cat Food
| Flavor: | Chicken |
| Food texture: | Pâté |
| Protein: | 10% |
| Size: | 3 oz. x 24, 5.5 oz. x 12 |
Instinct’s Original Grain-Free Cat Food is a pâté that comes in two sizes and is grain-free. The first three ingredients are whole meats, including chicken, turkey, and chicken liver, which can help build your cat’s muscles. It doesn’t contain any animal by-products, grain, wheat, corn, or artificial preservatives or colors. It has omega fatty acids to improve your cat’s skin and coat, and the cans are BPA-free.
The disadvantage is that the texture of this food is also quite loose and almost runny, which may or not be a bad thing.
5. Instinct Limited Ingredient Diet Rabbit Dry Cat Food
| Flavor: | Rabbit |
| Food texture: | Dry |
| Protein: | 35% |
| Size: | 5 and 10 lbs. |
Instinct’s Limited Ingredient Cat Food comes in two sizes and has limited ingredients, which also works for cats with food sensitivities. It is only made with one animal protein (rabbit) that is freeze-dried, and it doesn’t contain any grains, dairy, eggs, fish, wheat, or artificial preservatives or colors. It does have natural antioxidants and omegas to boost the immune system and the skin and coat.
However, some cats might experience stomach upset after eating this food, and it does tend to be rather smelly. Also, the food is quite dark in color — almost black — but this is normal because it has a raw coating.
6. Stella & Chewy’s Freeze-Dried Raw Cat Food
| Flavor: | Chicken |
| Food texture: | Freeze-dried morsels |
| Protein: | 45% |
| Size: | 5 oz., 8 oz., 18 oz. |
Stella & Chewy’s Freeze-Dried Raw Cat Food is high in protein because it’s raw food but conveniently freeze-dried to help preserve the nutrition. You can feed it as is to your cat or rehydrate it with water. This food is made in the U.S. and contains only organic fruits and vegetables. It doesn’t contain any fillers, gluten, grains, or artificial flavors or colors.
On the negative side, it is expensive, and some cats might not want to eat it. You might also find that the morsels are big for a small cat.
Buyer’s Guide: Selecting the Best Cat Foods for Hyperthyroidism
We have a few more things for you to consider before you make your first purchase of a new cat food. It’s best to be well-informed, particularly because this kind of food is expensive, so you’ll want to consider every aspect beforehand.
Cat Food Ingredients
This is the most essential part of choosing food for your cat. If you want to give your cat food that does not contain iodine or at least a reduced amount, it’s important to know what ingredients naturally have iodine:
| Seafood: | Fish, shrimp, seaweed |
| Dairy products: | Yogurt, cheese, milk |
| Egg: | Mainly yolks |
| Salt: | Iodized table salt |
So, before you purchase your cat food, always read the ingredients list first. Check that the ingredients containing iodine are minimal or not included and that the first three to five ingredients should be whole meat whenever possible.
Most foods don’t list the amount of iodine contained, so you’ll want to contact the manufacturer or look through reviews to find out this information. In general, it is recommended that your cat’s food should contain less than 0.32 ppm of iodine to be on the safe side; only products number one and two in this list stay under that limit, thus they are considered dietary treatments.
Of course, if your cat doesn’t like chicken or has a food sensitivity to it, you’ll want to look for different flavors.
The Best Cat Diet
Cats with hyperthyroidism should have a diet with 5–10 % carbohydrates, 50–70% protein, and 30–40% fat. Generally speaking, a diet that is high in protein and low in carbohydrates and has a moderate amount of fat is what you need to be looking for.
Since cats with hyperthyroidism tend to lose weight, they need the extra protein and fat to help them put on weight and to contribute to a healthy coat. A cat with hyperthyroidism tends to have a rather ratty-looking coat.
It’s a balancing act because older cats might have other issues beyond hyperthyroidism, such as diabetes or kidney disease. It’s thought that canned food is better than dry for the extra water content.
Both radioactive therapy and surgery cure hyperthyroidism and feeding a high-protein diet can help a cat recover the muscle and weight lost during the disease process. However, it is fairly common for cats to be diagnosed with renal disease after radioactive therapy. This happens because hyperthyroidism was masking the diagnostic markers of renal disease on the cat’s blood samples, once the hypothyroidism is resolved, the renal disease becomes evident in the blood parameters.
High protein diets are contraindicated for renal disease and the cat will need a different dietary approach. This is why it is very important to follow up with your veterinarian to find out what is the best diet specifically for your cat’s case and condition. Each cat is unique and feeding the right diet will make a huge difference in their health.
Dietary Treatments and Multiple Pets
Always speak to your vet about your cat’s diet and possible choices in food before you purchase anything. If you will try a dietary treatment, it’s important to note that once you’ve put your cat on a special prescription diet to treat their hyperthyroidism, you shouldn’t feed them anything else — no treats and no other food.
Some of these special foods, particularly the prescription ones, are only meant for cats with hyperthyroidism. If you have other pets in the house that like to eat your cat’s food, you’ll need to find a way to feed your cat and prevent the rest of the animals from eating it, and vice-versa.
High-quality cat food is an important part of fostering a long and healthy life for your cat but the right cat food and water dish will promote good posture, offer whisker relief, and aid in good digestion. The Hepper NomNom Cat Bowl is our favorite bowl since it offers all of the above and is beautifully crafted to meet modern home stylings. The wide tray design catches any food and water spills and the entire setup is dishwasher safe. Learn more about the Hepper NomNom Cat Bowl here.
At Pet Keen, we’ve admired Hepper for many years and decided to take a controlling ownership interest so that we could benefit from the outstanding designs of this cool cat company!
Conclusion
If you’re on the lookout for the best overall cat food to help with your cat’s hyperthyroid, Hill’s Prescription Diet y/d Thyroid Care Cat Food is the best bet for dietary treatment because it’s specially designed for this condition. You’ll need to speak to your veterinarian about the best value dietary treatment option Hill’s Prescription Diet y/d Thyroid Care Cat Food. It’s expensive but very effective!
Wellness Complete Health Cat Food is a better good high protein choice for a cat that is recovering from radioactive therapy treatment and has not been diagnosed with kidney disease.
We hope that our reviews will help you to be informed and know about the different options of food for your cat. Hopefully, the right diet, medication, or treatment will see your cat get back to optimal health as soon as possible.
- You may also be interested in: 10 Best Cat Foods for Kidney Disease (Low Phosphorus)
Featured Image Credit: Nils Jacobi, Shutterstock
