Pet Food Ingested Is Not
Associated with Yeasts on the Skin

Two patients shown exhibiting forms of the presence of yeast: on the feet and on the abdomen.
      There is an urban myth running rampant in the pet world regarding pet food and grain. Many on-line sources by self appointed experts advise people to have their pets with skin problems begin a “grain-free” diet as a cure for what ails them and that feeding foods high in carbohydrates will cause yeast on the skin. Guess what? Those cases often end up at Animal Dermatology Clinic, in order to determine the real triggers for the pets’ skin or allergy problems.
      Food has become entrenched among laypeople as a very common cause of skin disease and while it can be an allergic trigger it is a far less common trigger than generally considered by those same individuals. Celiac disease has become a well-known ailment in people, where sufferers cannot eat grain. And it is true that a pet can be allergic to grain, but it is usually the protein that is the culprit. Still, a true food allergic pet is not as common as is believed.
      One of the key fallacies of these self-appointed experts is the advocating of grain restriction of a pet with yeast.
The most common yeast on the skin of dogs and cats is Malassezia pachydermatis and there are a number of reasons for a pet to develop overgrowth and in almost all cases it is usually a SECONDARY symptom. A very common underlying primary cause are allergies which lead to defects and changes in the skin that allow for favorable microclimates for the yeasts to grow and create complicating factors for a patient.
      The rumor that pets ingesting grain or any carbohydrate will lead to yeast growth on the skin of the pet is not true. There is no scientific evidence that exists to support this as fact but it is commonly proposed by some pet food and supplement sellers in their marketing efforts.

Fact: A nutritious balanced diet is required for a pet. No one disagrees with this statement, except the anti-grain groups which strongly believe that grain negatively impacts a pet’s immune system, thereby causing yeast growth.
Excluding the rare dog with a true allergy, there is no evidence to support claims that grains cause health problems. (Central Veterinary Conference, 2011)
Myth: Dogs are carnivorous, therefore their digestive systems are not suited to grain.
It is frequently claimed, based primarily on the fallacious logic of “evolutionary nutrition,” that dogs are incapable of digesting grains or that these make poor nutrient sources in dog foods. Extensive evidence from laboratory research and feeding trials illustrates this is false and that cooked grains are excellent energy sources and can also provide protein and other important nutrients to dogs.1,2

Fact: When baking bread or making beer, the driving ingredient for yeast growth is sugar. Many food items containing yeast require the trigger of sugar to “grow” that yeast. And through the popularity of human dieting trends, most people know that the consumption of grains and carbohydrates are energy foods that metabolize into sugar in the body.
      This is not the same physiological process that feeds Malassezia in an affected pet. Consumption of grains and carbohydrates do not encourage yeast growth. (see chart below in printed newsletter)
      A person with athlete’s food (a fungal infection on the foot and remember, yeasts are a form of fungus) does not exacerbate the condition by eating a slice of toasted bread!
      If your pet has an odorous smell and greasy coat, it may be evidence of a yeast infection. Ask your veterinarian for guidance. Remember, yeast is a secondary condition and identifying the underlying cause is the goal.

Source: Rusty Muse, DVM, ACVD, Don Fruta, Marketing Director, Animal Dermatology Clinic

1. Walker JA, Harmon DL, Gross KL, Collings GF. Evaluation of nutrient utilization in the canine using ileal cannulation technique. Journal of Nutrition 1994;124(12 Suppl):2672S-2676S.
2. Gross KL, Wedekind KJ, Cowell CS, Schoenherr WD, Jewell DE, et al. Nutrients. In: Hand MS, Thatcher CD, Remillard RL, Roudebush P, editors. Small animal clinical nutrition. 4th ed. Topeka, KS, US: Mark Morris Institute; 2000. p. 21-107.

New Column: Ask the Dermatologist
Submit your questions now!

      In the upcoming months, Derm Digest will print selected questions from readers. Questions relating to pets’ skin, chronic ear conditions and other dermatology related questions and greatest general interest will get priority.
Have a question about food allergy? Will a raw diet cure skin problems? What about grain-free? How often should I bathe my dog? Are smelly ears normal? What is the most common allergy seen in dogs? Can a cattle dog be allergic to cows?
      Unfortunately, we cannot answer specific questions which would require an examination of your pet; it is impossible for any veterinarian to make a diagnosis of an animal without a physical examination. So a question along the lines of “My dog has this red spot on his leg, what is it?” cannot be answered.
      You’ve read and heard a lot of information about how to treat skin problems yourself…why not ask the experts?
Go to and use the Contact Page with a valid email address. In the Comments box, start your message with ‘NEWSLETTER QUESTION:’
We look forward to hearing from you!

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