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Dog Food Ingredients

Mike Sagman


Mike Sagman
Mike Sagman

Mike Sagman


Dr Mike Sagman is the creator of the Dog Food Advisor. He founded the website in 2008, after his unquestioning trust in commercial dog food led to the tragic death of his dog Penny.

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Updated: March 7, 2024

The following items represent some of The Dog Food Advisor’s most frequently asked questions about dog food ingredients.

What do the red items on an ingredients list mean?

Red ingredients are not always “bad”. They are only controversial. And when they are “bad”, some can be more troubling than others.

Corn would be a good example. You may find some 4 and 5-star dog foods that contain a few red items (like corn).

But they’re typically only minor issues — not nearly as worrisome as a suspected cancer-causing ingredient.

I’ve heard rosemary extract causes seizures. Is this true?

Rosemary is frequently used in dog food as a natural anti-oxidant and preservative.1 It’s also considered an anti-cancer agent.2

However, we’ve never been able to find any scientific studies linking rosemary extract with seizures in dogs. We’ve only found mention of its potential relationship in humans. And then, only rarely in subjects prone to epileptic seizures in the first place.3

Can beet pulp cause ear infections or stain a dog’s fur?

There are many rumors regarding the use of beet pulp in dog food. This fiber-rich ingredient has been accused of causing numerous canine maladies.

Some say it produces reddish tears that stain the facial fur of light-colored dogs. Yet beet pulp isn’t even red in color. It’s white.

Others claim beet pulp causes ear infections.

However, we’ve never found any scientific studies factually linking this ingredient to any of them.

Which ingredients most likely contain ethoxyquin?

Ethoxyquin is most likely associated with fish meals. But not raw fish. Because fish meals are rarely used in canned foods, most wet products can be considered ethoxyquin free.

As a pet food ingredient, is yeast bad for dogs?

Yeast can be a controversial item. Although yeast can sometimes be a by-product of the beer making industry, this ingredient can contain up to 45% protein… and is rich in other healthy nutrients.

Fans believe yeast repels fleas and supports the immune system.

Critics argue yeast ingredients can be linked to allergies. This may be true, but (like all allergies) only if your particular dog is allergic to the yeast itself.

What’s more, a vocal minority insist yeast can increase the risk of developing the life-threatening condition known as bloat. However, this is something we’ve not been able to scientifically verify.

In any case, unless your dog is specifically allergic to yeast, most experts consider the ingredient a healthy addition.

I’ve heard that yeast ingredients causes ear infections in dogs. Is this true?

So far, we’ve never found any scientific articles linking canine ear infections to the yeast ingredients found in dog food.

In most cases, yeast infections are caused by living organisms found in (or on) a dog’s body itself. They are usually associated with other problems… like allergies or mite infestations.

Is garlic good or bad for a dog?

Garlic can be a controversial item. Although many favor the ingredient for its claimed health benefits, garlic (in rare cases) has been linked to Heinz body anemia in dogs.4

In addition, garlic is also officially classified as “toxic to dogs” by the Poison Control Center of the ASPCA.5

So, even when used in only small amounts, one must weigh the questionable benefits of feeding garlic against its proven tendency to cause subclinical damage to the red blood cells of the animal.6

Is sodium selenite good or bad for a dog?

Selenium is an essential mineral for both dogs and humans.

However, all minerals can be found in a dog food in various forms (such as elemental selenium and sodium selenite). And each form can have a different toxic threshold before it can be considered dangerous.

According to AAFCO, the maximum amount of selenium permitted in a dog food is 2.0 mg/kg… a figure which is 18 times the minimum (0.11 mg/kg) for this mineral.7

However, the National Academy of Science has not yet determined the safe upper limit (SUL) for most minerals… even selenium.

Although no one can assure you every dog food will be 100% safe from the potential long term build-up of specific minerals, one can take at least some comfort in the apparently safe margin between the AAFCO minimums and the maximums for selenium.

How can I be sure the vitamin and mineral content of a food is safe?

Technically speaking, you can almost never be sure. That’s because other ingredients (like grains, meats and bone) naturally contain minerals… before a dog food manufacturer actually adds the vitamin and mineral supplements to the recipe.

So, unless you test each and every batch of food, you never truly know whether you are exceeding the (still unestablished) safe upper limit of a mineral.

What’s the better source of essential omega-3 fatty acids for a dog… fish oil or plant oil?

There are many different kinds of essential omega-3 fatty acids. Yet not all of them are created equal.

Fish oil contains the prized EPA and DHA variety. These two fatty acids possess the highest bio-availability to dogs and humans.

On the other hand, plant-based sources of omega-3 oils (especially flax seeds) contain a much higher content of ALA (an omega-3 fat not as readily utilized by the body).

Yet ALA can be converted to EPA and DHA by the animal. However, this conversion process (of ALA to the superior EPA and DHA type) is notably limited (especially in dogs).

Bottom line? Fish oil is superior to flax and canola oils. But these plant-based omega-3 fats are probably better for a dog than no omega-3 at all.

What is methionine?

Methionine is an amino acid essential to both dogs and cats.

Methionine is added to dog food not only to increase the supply of the nutrient itself but also to acidify the animal’s urine. This is reportedly done to prevent unsightly discoloration of grass and shrubbery.

Methionine is also used to help prevent the formation of struvite crystals in the urine. But unfortunately, it can also increase the potential for oxalate-type kidney and bladder stones, too.


1: Bhale SD et al (2007), “Oregano and Rosemary Extracts Inhibit Oxidation of Long-Chain n-3 Fatty Acids in Menhaden Oil”, Journal of Food Science, Nov 2007, 10.1111/j.1750-3841

2: Teuscher E (2005), Medicinal Spices (First edition), Stuttgart: Medpharm

3: Burkhard, PR et al (1999), “Plant-induced seizures: reappearance of an old problem”, Journal of Neurology 246 (8): 667–670

4: Yamato et al, Heinz Body hemolytic anemia with eccentrocytosis from ingestion of Chinese chive (Allium tuberosum) and garlic (Allium sativum) in a dog, Journal of the American Animal Hospital Association 41:68-73 (2005)

5: Garlic, Poison Control Center, ASPCA

6: Sharon Gwaltney-Brant DVM, Veterinary Toxicologist, Vice President and Medical Director, ASPCA Animal Poison Control Center in an interview with Dr. Bernadine D. Cruz for Pet Life Radio, Pets Have a Real Taste for Danger

7: Association of American Feed Control Officials, Official Publication, 2008 Edition, p. 131

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