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Ingredient file // Vitamin or mineral

Calcium Iodate

A useful iodine dose, not a calcium boost

Calcium iodate is a mineral salt added in tiny amounts to supply iodine. Dogs need iodine to make thyroid hormones, but the total dose matters: too little or too much can disrupt thyroid function. Its calcium contribution is negligible.

What it is
A manufactured mineral salt added to dog food as a measured source of iodine.
Made from
Iodine compounds and a calcium compound
Main job
Iodine for thyroid hormones
Typical amount
Milligrams per kilogram, depending on other iodine sources
Watch for
Extra iodine supplements alongside complete food
Not the same as
Calcium iodide

Our read // In our catalog

In 1 of every 5 foods we track

Share of foods that list it

22%

548 of the 2,533 foods with an ingredient list on file, from 35 brands. 513 dry dog food, 28 wet dog food, 4 dog food topper.

Each square is 1% of the catalog

Where it sits on the label

Median position 46. In the top five of 0 foods, so it is usually a minor ingredient.

Top five List position, heaviest first

Above the salt

3%

Usually listed after the salt, which caps it at roughly 1% of the recipe in 97% of foods.

Price per lb

Foods with it $3.25
All foods $3.23

Median of the cheapest bag price across 413 priced foods, about level with the catalog. The price is the food's, not the ingredient's.

Who leans on it

19%

of the foods that list it are from Blue. 35 brands use it in total.

What it is

How it is made

One documented chemical industry route recovers iodide from liquid left after making organic fluorine compounds. Oxidation and calcium addition yield crystals that can enter feed production. This is one route, not a description of every supplier's process.3,5

  1. 01 // Source Iodide-rich liquid A patented route starts with an iodide-containing waste solution from chemical production.
  2. 02 // Process Oxidized to iodate Chlorine converts dissolved iodide to iodate in the liquid.
  3. 03 // Process Calcium added Calcium chloride reacts with the iodate, causing calcium iodate crystals to separate from the liquid.
  4. 04 // Process Filtered and dried The crystals are filtered, washed with cold water and dried.
  5. 05 // Output Calcium iodate crystals The dried ingredient enters feed supply; anhydrous and hydrated products have different iodine percentages.

What is in it

Composition, dry matter

64.4

% iodine

Average iodine in tested anhydrous powder. The salt supplies iodine; the calcium that comes with such a small addition contributes little to finished food.

Iodine 64.1-64.8%3
Calcium 101-111 g/kg3
Calcium iodate 98.5-99.5%3

These figures describe anhydrous powder, treated here as dry material; the report gives no separate moisture correction. The calcium iodate row measures purity, not another nutrient. Hydrated or coated products have different percentages.3

Why it is in the bag

What the manufacturer gets

  1. 01

    Supplies measured iodine

    The thyroid uses iodine to make hormones. Assayed calcium iodate lets a formulator add a measured amount while accounting for iodine already present in other ingredients.1,3

  2. 02

    Retains iodine in storage

    A feed mineral trade group reports that iodates hold their iodine better than iodides exposed to moisture or other minerals. That is a formulation reason, although the sheet gives no dog food trial.6

  3. 03

    Uses a premix

    The EFSA feed additive authorization calls for calcium iodate to enter compound feed through a premix. Diluting a trace addition first makes it practical to distribute through a larger batch.3

  4. 04

    Uses recovered iodine

    A patent describes making feed additive crystals from iodide-bearing industrial waste liquid, giving that stream another use. It does not report what dog food makers pay for the ingredient.5

How much AAFCO's published dog food profile sets a minimum of 1 mg total iodine per kg of dry food; other iodine sources change the calcium iodate addition.4

Our read // The claims

What the evidence supports

Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.

  1. Brands say

    Supplies iodine dogs need for thyroid hormones

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    One iodine-deficient dog had normal thyroid hormone tests within 2 months of changing to iodine-supplemented food. EFSA accepts calcium iodate as an iodine source, but that case did not test this salt separately.1,3

  2. Vets say

    Too much iodine can disrupt thyroid function

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    In a controlled study of 18 puppies, the higher-iodine groups had lower thyroid hormone and higher thyroid stimulating hormone than controls. The study used potassium iodide, so the caution concerns total iodine rather than calcium iodate alone.2

  3. Brands say

    Keeps iodine stable throughout storage

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    A feed mineral trade group says iodates retain iodine during storage. EFSA's 2025 renewal review received no new feed stability data. Neither source shows that this choice improves the health of dogs eating finished food.3,6

  4. Brands say

    Its calcium helps build strong bones

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    Tested powder contained 101 to 111 g calcium per kg, but recipes use the powder in trace amounts to supply iodine. That contributes negligible calcium to the food. The name does not make it a calcium supplement.3,4

Straight answers

What owners ask

  1. Q01

    Is it just filler?

    No

    It has a specific job: supplying iodine for thyroid hormone production. The amount needed is too small to bulk up a recipe or meaningfully change its protein, fat or calories.3,4

  2. Q02

    Does it treat hypothyroidism?

    No

    One dog with proven dietary iodine deficiency recovered after a diet change. That case does not mean calcium iodate treats other causes of hypothyroidism, and an ingredient list cannot identify the cause of abnormal thyroid tests.1

  3. Q03

    Can the label show the dose?

    Usually no

    Ingredients are listed by weight without their individual amounts, and the standard guaranteed analysis does not require an iodine figure. If iodine intake needs tracking, ask the maker for measured total iodine in the finished food.7

Who uses it

Brands, best sellers and the company it keeps

Top brands, by foods that list it

  1. Blue 105
  2. Nulo 76
  3. Wellness 64
  4. Stella & Chewy's 45
  5. Horizon 26
  6. Earthborn Holistic 24
  7. Victor 20
  8. Verus 17
  9. NutriSource 16
  10. Blue Seal 15

Plus 25 more brands.

Amazon best sellers that list it

  1. #1 Blue Life Protection Formula Adult Chicken and Brown Rice Recipe Dry Dog Food
  2. #5 Blue Life Protection Formula Adult Small Breed Chicken and Brown Rice Recipe Dry Dog Food
  3. #27 Blue Life Protection Formula Senior Chicken and Brown Rice Recipe Dry Dog Food
  4. #30 Blue Life Protection Formula Puppy Chicken and Brown Rice Recipe Dry Dog Food
  5. #35 Blue Life Protection Formula Small Breed Senior Chicken and Brown Rice Recipe Dry Dog Food
  6. #36 Purina One SmartBlend Healthy Weight High Protein Formula Adult Premium Dry Dog Food
  7. #51 Blue Wilderness Adult Chicken plus Grains Recipe Dry Dog Food
  8. #54 Purina Pro Plan Small Breed Beef And Rice Dry Dog Food

Rank on Amazon's dog food best seller list, checked October 2026.

Usually listed with, share of the foods that list it

  1. Chicken Fat 51%
  2. Flaxseed 49%
  3. Chicken Meal 46%
  4. Peas 43%
  5. Natural Flavor 33%
  6. Chicken 30%
  7. Barley 28%
  8. Brown Rice 28%
  9. Oatmeal 26%
  10. Turkey Meal 24%
  11. Lentils 19%
  12. Dried Plain Beet Pulp 17%

Our read // On the bag

Read it as iodine, then check the food

Calcium iodate near other mineral ingredients supplies a small amount of iodine; its list position cannot reveal the dose. Check that the food is labeled complete and balanced for your dog's life stage. If iodine intake needs monitoring, request the finished food's measured total iodine from the maker.

Sources

What we read

Checked September 1, 2026.

  1. 1 Case Report: Diet-associated iodine-deficiency goitrous hypothyroidism in a dog: a longitudinal clinical, endocrine, and ultrasonographic evaluation Frontiers in Veterinary Science, 2026 // Journal
  2. 2 Morphologic Changes in the Thyroid Glands of Puppies Fed a High-Iodine Commercial Diet International Journal of Applied Research in Veterinary Medicine, 2003 // Journal
  3. 3 Assessment of the feed additives consisting of potassium iodide and calcium iodate anhydrous for all animal species for the renewal of their authorisation (AJAY EUROPE SARL) EFSA Journal, 2025 // Journal
  4. 4 AAFCO DOG AND CAT FOOD AAFCO, 2013 // Regulator
  5. 5 Process for the preparation of crystalline calcium iodate Google Patents, 1983 // Database
  6. 6 Iodine sources EMFEMA, n.d. // Industry
  7. 7 Reading Labels AAFCO, n.d. // Regulator
An ingredient on its own tells you very little. What matters is how much of it there is and where it sits in the list. That is why we weigh the top five rather than reacting to any single name further down. Back to the wiki

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