Pet food discussions seem uniquely capable of getting readers of this blog excited. Let’s shake things up.

Recently a reader brought up a question in the discussion of corn as a pet food ingredient. The reader was curious about the allergenic effects of corn. Is corn likely to cause allergic reactions in dogs and cats?

Cats and dogs with food allergies most commonly suffer from skin and ear problems. Gastrointestinal upset also is possible.

Numerous studies have been performed to assess the most highly allergenic food ingredients. A paper published in the September, 2002 issue of Advances in Small Animal Medicine and Surgery attempted to tabulate the results of 22 different studies into a cohesive set of data. This “study of studies” has the advantage of large sample sizes that are likely to be statistically significant. It has the disadvantage of being authored by Philip Roudebush of the Hill’s Science and Technology Center. Although I can’t see any evidence of data twisting in the paper, readers should be aware that the data were tabulated by a person employed by a pet food manufacturer. Consume as many grains of salt as you desire while reading the results.

The leading food allergens in dogs as determined by the study of studies are listed below. Numbers in parentheses indicate percent of food allergy cases caused by each ingredient. They do not indicate the likelihood that a pet will suffer an allergic reaction after consuming the ingredient.

  • Beef (34%)
  • Dairy (20%)
  • Chicken (20%)
  • Wheat (16%)
  • Egg (7%)
  • Lamb (5%)
  • Soy (5%)
  • Corn (3%)
  • Pork (2%)
  • Rice (2%)
  • Fish (1%)
  • In cats, the following allergens were found to be most problematic.

  • Beef (29%)
  • Dairy (29%)
  • Fish (23%)
  • Lamb (7%)
  • Chicken (7%)
  • Wheat (5%)
  • Corn (5%)
  • Egg (4%)
  • A different study of studies was published in April, 2006 in the online journal Critical Reviews in food Science and Nutrition. The authors were Belgian, and in a quick review of the matter I could not find evidence of links to pet food companies. Here are their conclusions.

    The leading allergens in dogs as determined by the authors are beef (36%), dairy (28%), wheat (15%), egg (10%), “diverse” (includes corn, rice, “biscuit”, chocolate [They’re feeding chocolate to dogs in Belgium?! Don’t they know it’s potentially toxic? And isn’t Belgian chocolate too good to give to dogs?], and gluten) (10%), chicken (9.6%), “canned foods” (8.6%), soy (6%), “dry foods” (6%), pork (4%), rabbit (1%) and fish (1%).

    The authors concluded that the leading allergens in cats are “commercial foods” (ingredient causing allergies undetermined) (25%), beef (20%), dairy (15%), fish (13%) “diverse” (includes penicillin, “brand’s essence”, gluten, and viscera) (11%), lamb (7%), poultry (5%), barley and wheat (5%), additives (2%), rabbit (1%) and egg (1%).

    Percentages in both studies may not add to 100 due to rounding.

    Readers are invited to post links to additional studies in the comments section.

    Photo: may cause allergic reactions in dogs. That leaves more for me!