The Best Low Iodine Cat Food

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If you’re looking for low-iodine cat food for your senior feline friend who’s a victim of hyperthyroidism, you’ve probably landed on the most updated article of 2023.

In the following article, I’ll walk you through everything you need to know before picking the ideal cat food option for you.

Here’s a Summary of Our Top Picks:

ImageProductDetails  Price
Hills-Prescription-Diet-yd-Feline-Thyroid-Health-Canned-Cat-FoodHill’s Prescription Diet y/d Feline Thyroid Health Canned Cat FoodTop PickCheck Price
Hills Prescription Diet Y/D Feline Thyroid Health Dry Cat FoodHill’s Prescription Diet Y/D Feline Thyroid Health Dry Cat FoodRunner-UpCheck Price
Blue Buffalo Wilderness High Protein Grain FreeBlue Buffalo Wilderness High Protein Grain FreeBudget PickCheck Price

Top 3 Low Iodine Food Picks for Hyperthyroidism

Finding good quality cat food can be quite overwhelming with all the options on the market, let alone if you’re narrowing it down to low iodine levels as well.

To make the search process easier for you, I’ve compiled a review list of the best low-sodium cat foods that you may find out there. Let’s have a quick look at each one of them!

1. Hill’s Prescription Diet y/d Feline Thyroid Health Canned Cat Food

Hill's Prescription Diet y/d Thyroid Care with Chicken Canned Cat Food, Veterinary Diet, 5.5 oz, 24-pack wet food

Kicking off the list with one of the best low iodine options on the market. Hill’s Prescription Diet y/d is a specialized formula that is specifically formulated for cats suffering from hyperthyroidism.

Must Read: best Royal Canin Ultamino cat alternatives

According to Hill’s, this formula is extremely low in iodine and you’ll be able to notice an improvement in the thyroid health of your cat in 3 weeks.

The low concentration of iodine will deplete all the resources needed by the thyroid gland to produce more thyroid hormones, causing it to stop. This makes it an excellent alternative to medications and radiotherapy.

However, you need to know that your cat will have to stick to that diet for life to prevent the thyroid gland from relapsing.

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Luckily, this canned wet food has a meaty flavor because it contains liver, pork and its by-products, chicken as well as water and cornflour. This means that your cat will enjoy eating it.

In addition to the good flavor, the formula is also rich with multiple types of vitamins and minerals. These elements help the cat’s body to maintain a healthy bladder, heart, kidney, and even skin.

It has a decent protein concentration of about 27%, which is important for the cat to maintain its muscle mass as it gets older. This can help the senior cats avoid the muscle-wasting syndrome that comes with hyperthyroidism.

What I Liked

  • Extremely low in iodine
  • An ideal alternative to radiotherapy and medication
  • Beef-rich formula

What I Didn’t Like

  • Requires a vet’s prescription

2. Hill’s Prescription Diet Y/D Feline Thyroid Health Dry Cat Food

Hill's Prescription Diet y/d Thyroid Care Dry Cat Food, Veterinary Diet, 8.5 lb. Bag (Packaging May Vary)

If you enjoyed Hill’s Prescription y/d canned food but you’re looking for an alternative that doesn’t need a prescription from your cat’s vet, this one is a great option to go for. It’s also a great option for cats that love kibbles.

Although you don’t need a vet’s prescription to get this type of food, it’s still preferable to only go for it when it’s recommended by them.

Similar to the prescription diet, this one is also extremely low in iodine, which is great for low and medium-level hyperthyroidism.

However, this one doesn’t contain the same ingredients. While the wet y/d version is rich in pork and chicken, this one is mainly corn gluten meal, whole grain corn, pork fat, soybean mill run, and egg products.

Similar to the wet y/d version, this one is also able to improve the health of the thyroid gland in three weeks, which is clinically proven.

Since your cat has to only consume this food for it to work, Hill’s made sure that the product is rich in all the ingredients needed for a healthy life. For example, it’s formulated with Hill’s S+OXSHIELD, which prevents the formation of urinary crystals.

The formula is also rich in omega-3 and fatty acids, which are essential for inflammatory relief, especially in senior cats.

What I Liked

  • An ideal alternative to prescription diets with very low iodine
  • The S+OXSHIELD formula is great for bladder health
  • Rich in ingredients that are important for senior cats’ health

What I Didn’t Like

  • While it has protein, it lacks the meaty value

3. Blue Buffalo Wilderness High Protein Grain Free

Blue Buffalo Wilderness High Protein, Natural Adult Dry Cat Food, Salmon 11-lb

Unfortunately, prescription diets that care specifically for hyperthyroidism can get easily expensive.

Also, they only work if you only use them, which can be quite difficult to maintain if you’re on a budget.

Luckily, this excellent formula from Blue Buffalo is a great solution to many of these problems.

While it contains traces of potassium iodide, the formula is still much lower in iodine than other formulas on the market.

Moreover, the formula is low in carbs and very high in proteins. This means that it won’t promote insulin tolerance while fighting the wasting symptoms accompanied by hyperthyroidism.

What I Liked

  • Ideal for buyers on a budget
  • Requires no prescription
  • Has a very high concentration of proteins
  • Rich in minerals and vitamins

What I Didn’t Like

  • Relatively higher iodine than prescription diets

How is Iodine Listed in Cat Food?

When checking the ingredients list on cat food labels, look for iodine listed as potassium iodide. This is the most common supplemental form added to pet foods.

Iodine levels can also be listed in the guaranteed analysis section as a maximum percentage. However, this is not required to be included. Look for cat foods specifying “low iodine” or vet-prescribed formulas for hyperthyroidism to ensure minimal amounts.

DIY Guide: Homemade Low Iodine Cat Food

You can also make homemade low iodine cat food. Choose recipes without seafood, eggs, or dairy as these contain higher iodine levels. Some ingredient options include:

  • Meat: Chicken, beef, pork, lamb (with fat trimmed)
  • Carbs: Brown rice, oats, barley
  • Veggies: Carrots, peas, sweet potato
  • Oils: Olive, coconut, corn, canola

Double-check all ingredients before use and consult your vet for proper nutritional balance. Portion-controlled freezing in ice cube trays makes homemade food easy to thaw and serve.

Purina Thyroid Cat Food

Purina offers both prescription and over-the-counter thyroid support formulas, including:

Discuss these foods with your vet to see if they may be suitable options for your cat.

Royal Canin Thyroid Cat Food

Royal Canin veterinary diet Thyroid+ was specially created for cats with thyroid issues. It contains:

  • Restricted iodine levels
  • Increased levels of EPA and DHA to support skin/coat health
  • L-carnitine to help maintain lean muscle mass

This prescription dry food can only be obtained from your veterinarian. There is also a Thyroid+ canned version.

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What are the drawbacks of low-iodine diets on cats?

Iodine is only utilized in the body in the production of thyroid hormone almost exclusively. That’s why a cat with hyperthyroidism shouldn’t suffer from any further complications while on that diet.

Can a cat consume dietary supplements while eating low-iodine cat food?

In most cases, dietary supplements might also include iodine. In that case, it shouldn’t be consumed. However, it’s ok to consume vet-approved dietary supplements that don’t have iodine.

What are the symptoms of hyperthyroidism?

There are many symptoms that come with hyperthyroidism, such as:
– Noticeable weight loss
– Fast heart rate
– Increased appetite
– Increased activity
– Poor hair coat health


There you have it. A complete guide with everything you need to know about low-iodine cat food and hyperthyroidism in cats.

As you can see, iodine-restricted diets are proven clinically to enhance thyroid health. However, you need to remember that it won’t fully cure your cat.

Yet, it’s a perfect alternative to invasive surgeries and radiotherapy, especially for a senior cat.

I recommend Hill’s Prescription Diet y/d Feline Thyroid Health Canned Cat Food as the best low-iodine cat food on the market. The formula is made by expert vets and it’s guaranteed to boost the health of the thyroid gland.