Prescription cat food for hyperthyroidism is specially formulated to have low levels of iodine, which helps reduce the production of excess thyroid hormone. While it won’t cure hyperthyroidism in cats, it can support their recovery and help them maintain or regain muscle mass when used in conjunction with proper treatment.
One popular brand that veterinarians often recommend is Hill’s Prescription Diet y/d Thyroid Care cat food. This cat food is formulated to contain 0.1 ppm of iodine (measured as dry matter) and has been clinically proven to decrease thyroid hormone production. However, it’s important to note that Hill’s also offers a dry cat food version of this formula, which may contribute to other health problems due to a lack of moisture in the diet.
If you’re looking for an alternative to prescription cat food, we’ve compiled a list of wet cat foods that are species-appropriate and have lower-than-average iodine levels. It’s important to consult with your veterinarian before making any changes to your cat’s diet, as they are the best person to recommend treatment options for hyperthyroidism in cats.
At A Glance: Best Cat Food for Hyperthyroidism to Buy
If you’re looking for a quick overview of the products reviewed in this article, check out the comparison table below:
| Brand | Features |
|---|---|
| Hill’s Prescription Diet y/d Thyroid Care cat food | Low iodine levels, clinically proven to decrease thyroid hormone production |
| Other wet cat foods with lower iodine levels | Species-appropriate, non-prescription products |
Why Trust Pawsoha
At Pawsoha, our recommendations are the result of extensive research conducted by our team of veterinary advisors. We have evaluated numerous prescription and non-prescription cat foods, comparing their iodine content to the recommended minimum level of 0.60mg/kg (measured as dry matter) set by the AAFCO.
To ensure the accuracy of our recommendations, we purchased all the cat foods at full retail price and tested them in-house with our team members’ own cats. Our testing process includes brand research, nutritional analysis, and evaluation of the product’s appearance, aroma, texture, consistency, and packaging. Ultimately, we rely on our cats’ responses to gauge the flavor and general appeal of the food.
How We Selected the Best Cat Foods for Hyperthyroidism
Our selection process involved hours of research on dietary management for hyperthyroidism and the evaluation of both prescription and non-prescription cat foods. We gathered nutritional information for products from over twenty highly-rated brands, contacting the brands directly when necessary.
Using dry matter values, we narrowed down our selection to seven products with the lowest iodine levels. We excluded fish-based foods and those containing seaweed-based ingredients like kelp, dulse, and agar-agar.
It’s important to note that the cat foods on our list are not specifically formulated for thyroid care, so their iodine levels are higher than those in prescription diets. However, we selected foods that tested as close to the minimum recommendation of 0.60mg/kg iodine (measured as dry matter) as possible. All the foods on our list tested under 3.0mg/kg, measured as dry matter.
What to Look for in the Best Cat Food for Hyperthyroidism
When choosing a cat food for a cat with hyperthyroidism, there are several factors to consider:
Hyperthyroid Cats Need Highly Digestible Protein
Hyperthyroid cats have an overactive metabolism, and many of them are seniors who require high protein and energy levels to maintain muscle mass. Choose cat foods with over 50% of calories from protein, focusing on species-appropriate and highly digestible sources. Avoid foods with high-protein fillers like pea protein, potato protein, wheat gluten, and corn gluten meal.
Choose a Diet with Less Than 10% Carbohydrates on a Dry Matter Basis
Hyperthyroidism can raise blood glucose levels and lead to insulin resistance and impaired glucose tolerance. It’s important to feed cats with hyperthyroidism controlled levels of dietary carbohydrates. Look for cat foods that have less than 10% carbohydrates on a dry matter basis.
What to Avoid When Feeding a Hyperthyroid Cat
When feeding a cat with hyperthyroidism, there are certain foods to avoid:
Avoid Fish-Based Foods
Studies have shown that cats who prefer fish-based canned cat food or flavors like liver and giblets have an increased risk of developing hyperthyroidism. Fish and other ocean creatures have higher levels of iodine than other foods, which may be part of the connection. If you’re concerned about your cat’s diet, speak with your veterinarian.
Most Fish is Contaminated with Toxins, Including PBDEs
Fish-based foods, including canned fish, may contain toxins like PBDEs, which are known endocrine disruptors. These chemicals can disrupt thyroid function and may contribute to hyperthyroidism in cats.
If Feeding Canned Food, Ensure That the Can is BPA-Free
Canned cat food often comes in cans with epoxy linings containing BPA, which can act as a thyroid receptor antagonist and alter thyroid function. Look for BPA-free cans to reduce the risk of thyroid problems in your cat.
Don’t Feed Your Cat Soy
Soy can disrupt normal thyroid functioning and increase the risk of developing hyperthyroidism. Studies have shown that a soy-based diet can significantly increase thyroxine and free thyroxine concentrations in cats, affecting the amount of thyroid hormone produced by the body.
Select a Low-Iodine Diet
Since iodine plays a role in thyroid hormone production, cats with hyperthyroidism should eat a low-iodine diet to avoid further stimulation of the overactive thyroid glands.
Should You Feed Your Cat a Prescription Diet for Hyperthyroidism?
Prescription diets for hyperthyroidism are designed to have low levels of iodine, slowing down thyroid hormone synthesis and reducing the symptoms of hyperthyroidism. However, they do not fix an enlarged thyroid gland or prevent an adenoma from turning into a carcinoma.
If prescription options are limited or unavailable, it may be practical to feed your cat a high-protein, fish-free wet cat food with low carbohydrate content to manage their symptoms. Always consult with your veterinarian before making any changes to your cat’s diet.
How Much Iodine Does a Normal Cat Require?
Determining the exact dietary iodine requirements for cats is challenging due to variations in iodine concentration in different types of food. The National Research Council suggested a dietary iodine requirement for cats of 1.3 ppm in 2006, but newer research by Hill’s Pet Nutrition suggests that the requirement may be closer to 0.46 ppm.
Therapeutic diets with low iodine levels are limited, with Hill’s being the only brand to offer a prescription product for hyperthyroidism. Hill’s thyroid care wet cat food contains approximately 0.1 ppm iodine, which is considered very low. However, the long-term effects of an iodine-restricted diet on a cat’s health are still unknown, so it should be considered a temporary measure or used as a last resort for cats unable to undergo surgery or receive radioiodine therapy.