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Ingredient file // Fruit or vegetable

Shiitake Mushrooms

A tasty mushroom whose health claims outrun the data

Shiitake are farmed mushrooms, dried or freeze-dried and added mostly to toppers and fresh foods. They bring savory flavor and some fiber. The immune and antioxidant claims rest on one small beagle trial and on lab work.

Role in the food Does a job
What it is
Farmed shiitake mushrooms, usually dried or freeze-dried, then sliced or powdered and mixed into toppers and fresh recipes.
Made from
Shiitake grown on hardwood sawdust blocks or logs
Main job
Flavor and label appeal
Typical amount
Not published; a dog trial fed 800 mg per kg body weight
Watch for
Wild yard mushrooms are a different, real danger
Not the same as
Wild mushrooms

Straight answer

Is Shiitake Mushrooms safe for dogs?

Enjoy it as flavor, ignore the immune promise

Shiitake usually sits low in a topper or fresh food list, behind the meat, eggs and vegetables. There it adds flavor and a little fiber, not a measured health effect. Choose the food on its meat, its protein and its price, and do not pay extra for the mushroom.

Why it is in the food
Flavor and label appeal

Our read // In our catalog

In 1 of every 82 foods we track

Share of foods that list it

1%

39 of the 3,204 foods with an ingredient list on file, from 7 brands. 17 frozen dog food, 13 freeze-dried dog food, 5 dry dog food.

Each square is 1% of the catalog

Where it sits on the label

Median position 19. In the top five of 4 foods, so it is usually a minor ingredient.

Top five List position, heaviest first

Above the salt

26%

Usually listed after the salt, which caps it at roughly 1% of the recipe in 74% of foods.

Price per lb

Foods with it $7.87
All foods $3.25

Median of the cheapest bag price across 3 priced foods, 142% above the catalog. The price is the food's, not the ingredient's.

Who leans on it

49%

of the foods that list it are from Smallbatch. 7 brands use it in total.

What it is

How it is made

Shiitake are farmed, not foraged. Growers raise them indoors on hardwood sawdust blocks or outdoors on hardwood logs, then sell the caps fresh or slice and dry them for long storage.1,4,5

  1. 01 // Source Hardwood substrate A typical sawdust mix is 80% oak sawdust and 18% wheat bran, sterilized at 121°C for 3.5 hours.
  2. 02 // Process Spawn run The fungus grows through the wood. On outdoor logs this takes 9 to 18 months before mushrooms appear.
  3. 03 // Process Harvested Caps are picked about 75% open, and the stem is cut off because it is too woody to eat.
  4. 04 // Process Dried Slices are dehydrated, or whole mushrooms are frozen, freeze-dried and ground to powder, as in the one dog trial.
  5. 05 // Output Dried shiitake Dry slices or powder, mostly carbohydrate and fiber, weighed into toppers and fresh recipes.

What is in it

Composition, dry matter

20-56

% beta-glucan

The beta-glucan range across 10 cultivars, caps and stems. This is the fiber behind every immune claim on the bag, and it is mostly fiber.

Carbohydrate 58.8-66.1%3
Beta-glucan 20.1-56.5%2
Crude protein 14.7-17.7%3
Ash 2.2-4.6%3
Crude fat 1.1-2.1%3
Eritadenine 780 mg/kg1

Stems hold more beta-glucan than caps, and cultivar alone moves it by more than 20 points. Protein shifts with what the mushroom was grown on. Eritadenine is one freeze-dried powder sample.1,2,3

Why it is in the bag

Mostly there for savory flavor and the label

  1. Main nutrition
  2. Supporting nutrient
  3. Does a job
  4. Mostly filler

Makers add shiitake for savory taste, since it carries glutamate-type compounds and flavor nucleotides [4], and for the functional-mushroom story it lets a label tell [9]. Near the top of a topper's list it adds real carbohydrate and fiber; the caps measure 20 to 44% beta-glucan on a dry basis [2,3]. Far down a long list, which runs in order of weight [11], it is likely too little to change the food's nutrition. The one dog trial fed 800 mg per kg daily [1].1,2,3,4,9,11

  1. 01

    Savory, umami flavor

    Shiitake carry free glutamate-type amino acids and flavor nucleotides. Grown on standard oak sawdust, one analysis scored their umami at about 10 g of MSG per 100 g; rice straw substrates pushed it far higher.4

  2. 02

    A functional-mushroom story

    Brands sell shiitake for immune signaling, antioxidant protection and fat metabolism. The ingredient lets a label carry that story, whatever the amount in the recipe.9

  3. 03

    Carbohydrate with fiber

    Dried shiitake is about 59 to 66% carbohydrate on a dry basis, much of it beta-glucan fiber, with 15 to 18% protein and 1 to 2% fat. How much reaches the dog depends on an unpublished amount.2,3

How much No source publishes a pet food amount. The one dog trial fed 800 mg of dried powder per kg body weight daily, about 8 g for a 10 kg beagle.1

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

    Shiitake lowers cholesterol and boosts antioxidants in dogs

    Outruns the evidence

    Evidence

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

    One trial fed 4 healthy beagles 800 mg per kg body weight of freeze-dried powder for 4 weeks, against 4 untreated controls. Cholesterol fell 128 to 91 mg/dL, controls fell too, 120 to 110, and an antioxidant enzyme rose fivefold. No health outcome was measured.1

  2. Brands say

    Mushroom beta-glucans support your dog's immune system

    Outruns the evidence

    Evidence

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

    Shiitake is 20 to 56% beta-glucan on a dry basis. The dog beta-glucan trials in a 2024 review used yeast-derived products, and the authors called the dog evidence too limited to conclude. No trial has tested shiitake on dog immunity.2,7

  3. Owners say

    Shiitake helps fight cancer

    Outruns the evidence

    Evidence

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

    A 2026 meta-analysis of 22 human trials, 1,723 patients, found shiitake extracts added to cancer treatment improved response rates but not survival. Those were concentrated extracts, not a food ingredient, and no dog has been studied.8

  4. Owners say

    Mushrooms are toxic to dogs

    Outruns the evidence

    Evidence

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

    The Pet Poison Helpline team says grocery mushrooms sold for people are not considered toxic to dogs. The danger is wild species such as Amanita, the most toxic to dogs and people. Shiitake in a food is a farmed, known species.6

Straight answers

What owners ask

  1. Q01

    Is it just filler?

    Mostly flavor

    It is there for savory taste and the label story, not for nutrition. Calling it filler misses its flavor job, and calling it medicine overshoots the evidence, which is one 8-dog trial of blood markers.1,4

  2. Q02

    Is shiitake a protein source?

    No

    Dried shiitake runs about 15 to 18% protein and 59 to 66% carbohydrate on a dry basis. The meat and eggs listed around it carry the protein in the recipe.3

  3. Q03

    Is raw or freeze-dried shiitake safe?

    In dogs, so far

    Freeze-dried powder is uncooked, and 4 beagles ate it daily for 4 weeks with no signs of disease. In people, raw shiitake can cause a streaky rash from lentinan, which heating to 130 to 145°C inactivates.1,10

Who uses it

Brands, best sellers and the company it keeps

Top brands, by foods that list it

  1. Smallbatch 19 / 23
  2. Viva Raw 8 / 8
  3. Tucker's 4 / 25
  4. Wysong 3 / 20
  5. K9 Natural 2 / 8
  6. Northwest Naturals 2 / 5
  7. Dr. Marty 1 / 6

Foods that list it / all the brand's recipes we track.

Usually listed with, share of the foods that list it

  1. Broccoli 62%
  2. Green Beans 51%
  3. Carrots 41%
  4. Butternut Squash 33%
  5. Bok Choy 31%
  6. Ginger 26%
  7. Beef Heart 23%
  8. Beef Liver 23%
  9. Celery 23%
  10. Cranberries 21%
  11. Mixed Tocopherols 21%
  12. Sweet Potatoes 18%

On the shelf

Foods that list Shiitake Mushrooms

39 foods in our catalog list it, highest on the label first.

Tucker’s Boost Pork Butter Grain-Free Dog Food TopperTucker'sTucker’s Boost Pork Butter Grain-Free Dog Food TopperTopper // No. 5 on the labelTucker’s Boost Turkey Butter Grain-Free Dog Food TopperTucker'sTucker’s Boost Turkey Butter Grain-Free Dog Food TopperTopper // No. 5 on the labelWysong Optimize Wild Caught Salmon Grain-Free Dry Dog FoodWysongWysong Optimize Wild Caught Salmon Grain-Free Dry Dog FoodDry // No. 7 on the labelWysong Optimize Chicken Dry Dog FoodWysongWysong Optimize Chicken Dry Dog FoodDry // No. 7 on the labelViva Raw Complete Diet Lamb Frozen Dog FoodViva RawViva Raw Complete Diet Lamb Frozen Dog FoodFrozen // No. 14 on the labelViva Raw Complete Diet Rabbit Frozen Dog FoodViva RawViva Raw Complete Diet Rabbit Frozen Dog FoodFrozen // No. 15 on the labelSmallbatch Rabbit Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Rabbit Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 16 on the labelSmallbatch Lamb Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Lamb Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 17 on the labelDr. Marty Nature’s Blend Premium Origin Freeze-Dried Dog FoodDr. MartyDr. Marty Nature’s Blend Premium Origin Freeze-Dried Dog FoodFreeze-Dried // No. 20 on the labelNorthwest Naturals Nuggets; Bulk Meal Bars; Chubs Lamb Recipe Frozen Dog FoodNorthwest NaturalsNorthwest Naturals Nuggets; Bulk Meal Bars; Chubs Lamb Recipe Frozen Dog FoodFrozen // No. 21 on the labelNorthwest Naturals Nuggets; Bulk Meal Bars Bison & Beef Recipe Frozen Dog FoodNorthwest NaturalsNorthwest Naturals Nuggets; Bulk Meal Bars Bison & Beef Recipe Frozen Dog FoodFrozen // No. 24 on the labelK9 Natural Baked & Coated Grass-Fed Red Recipe Grain-Free Dry Dog FoodK9 NaturalK9 Natural Baked & Coated Grass-Fed Red Recipe Grain-Free Dry Dog FoodDry // No. 28 on the label
Show 27 more
Tucker’s Boost Chicken Butter Grain-Free Dog Food TopperTucker'sTucker’s Boost Chicken Butter Grain-Free Dog Food TopperTopper // No. 5 on the labelTucker’s Boost Beef Butter Grain-Free Dog Food TopperTucker'sTucker’s Boost Beef Butter Grain-Free Dog Food TopperTopper // No. 5 on the labelWysong Optimize Beef Heart & Liver Grain-Free Dry Dog FoodWysongWysong Optimize Beef Heart & Liver Grain-Free Dry Dog FoodDry // No. 8 on the labelViva Raw Complete Diet Duck Frozen Dog FoodViva RawViva Raw Complete Diet Duck Frozen Dog FoodFrozen // No. 15 on the labelViva Raw Complete Diet Turkey Frozen Dog FoodViva RawViva Raw Complete Diet Turkey Frozen Dog FoodFrozen // No. 15 on the labelViva Raw Complete Diet Chicken Frozen Dog FoodViva RawViva Raw Complete Diet Chicken Frozen Dog FoodFrozen // No. 15 on the labelViva Raw Complete Diet Pork Frozen Dog FoodViva RawViva Raw Complete Diet Pork Frozen Dog FoodFrozen // No. 16 on the labelViva Raw Complete Diet Beef Frozen Dog FoodViva RawViva Raw Complete Diet Beef Frozen Dog FoodFrozen // No. 17 on the labelSmallbatch Freeze-Dried Duck Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Freeze-Dried Duck Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 18 on the labelSmallbatch Small Batch Beef Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Small Batch Beef Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 18 on the labelViva Raw Pure Puppy Recipe Frozen Dog FoodViva RawViva Raw Pure Puppy Recipe Frozen Dog FoodFrozen // No. 19 on the labelSmallbatch Freeze-Dried Turkey Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Freeze-Dried Turkey Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 19 on the labelSmallbatch Chicken Small Bites Freeze-Dried Dog FoodSmallbatchSmallbatch Chicken Small Bites Freeze-Dried Dog FoodFreeze-Dried // No. 19 on the labelSmallbatch Raw Rabbit Sliders Frozen Dog FoodSmallbatchSmallbatch Raw Rabbit Sliders Frozen Dog FoodFrozen // No. 20 on the labelSmallbatch Beef Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Beef Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 21 on the labelSmallbatch Raw Beef Sliders Frozen Dog FoodSmallbatchSmallbatch Raw Beef Sliders Frozen Dog FoodFrozen // No. 21 on the labelSmallbatch Lamb Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Lamb Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 22 on the labelSmallbatch Raw Duck Sliders Frozen Dog FoodSmallbatchSmallbatch Raw Duck Sliders Frozen Dog FoodFrozen // No. 22 on the labelSmallbatch Frozen Raw Lamb Patties Frozen Dog FoodSmallbatchSmallbatch Frozen Raw Lamb Patties Frozen Dog FoodFrozen // No. 22 on the labelSmallbatch Frozen Raw Chicken Patties Frozen Dog FoodSmallbatchSmallbatch Frozen Raw Chicken Patties Frozen Dog FoodFrozen // No. 22 on the labelSmallbatch Chicken Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Chicken Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 23 on the labelSmallbatch Raw Pork Patties Frozen Dog FoodSmallbatchSmallbatch Raw Pork Patties Frozen Dog FoodFrozen // No. 23 on the labelSmallbatch Turkey Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Turkey Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 24 on the labelSmallbatch Raw Turkey Sliders Frozen Dog FoodSmallbatchSmallbatch Raw Turkey Sliders Frozen Dog FoodFrozen // No. 24 on the labelSmallbatch Duck Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Duck Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 26 on the labelSmallbatch Pork Sliders Freeze-Dried Dog FoodSmallbatchSmallbatch Pork Sliders Freeze-Dried Dog FoodFreeze-Dried // No. 26 on the labelK9 Natural Baked & Coated Cage-Free Poultry Recipe Grain-Free Dry Dog FoodK9 NaturalK9 Natural Baked & Coated Cage-Free Poultry Recipe Grain-Free Dry Dog FoodDry // No. 29 on the label

Sources

What we read

Checked October 1, 2026.

  1. 1 Shiitake mushroom powder supplementation increase antioxidative activity in dogs Frontiers in Veterinary Science, 2024 // Journal
  2. 2 Determination of Glucan Contents in the Fruiting Bodies and Mycelia of Lentinula edodes Cultivars Mycobiology, 2014 // Journal
  3. 3 Improvement of yield of the edible and medicinal mushroom Lentinula edodes on wheat straw by use of supplemented spawn Brazilian Journal of Microbiology, 2014 // Journal
  4. 4 Bioconversion of rice straw agro-residues by Lentinula edodes and evaluation of non-volatile taste compounds in mushrooms Scientific Reports, 2020 // Journal
  5. 5 Shiitake Production on Hardwood Logs Mississippi State University Extension, n.d. // University
  6. 6 My Dog Ate a Mushroom. Now What? PetMD (Pet Poison Helpline Veterinarian Team), 2025 // Industry
  7. 7 Translating Human and Animal Model Studies to Dogs' and Cats' Veterinary Care: Beta-Glucans Application for Skin Disease, Osteoarthritis, and Inflammatory Bowel Disease Management Microorganisms, 2024 // Journal
  8. 8 Lentinula edodes in Cancer Treatment: A Systematic Review and Meta-Analysis Integrative Cancer Therapies (Europe PMC record), 2026 // Journal
  9. 9 Shiitake Mushrooms Bernie's Best (Bernie's University), n.d. // Industry
  10. 10 Shiitake mushroom-induced flagellate erythema Oxford Medical Case Reports, 2026 // Journal
  11. 11 Animal Food Labeling and Pet Food Claims U.S. Food and Drug Administration, 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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