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Monday, June 22, 2015

Read Carefully....Corn Isn't Bad And Vets Haven't Sold Out

I've blogged a lot about nutrition in pets, especially the big myth that corn is a bad, worthless ingredient.  I still revisit these issues because I've developed a real interest in nutrition and because there is still so much misinformation out there about pet food ingredients.  For those who may not have read my previous posts, I would strongly recommend going back and doing so at the following links:

Nutrition Mythbusting
Nutrition Week #1
Nutrition Week #2
Nutrition Week #3
Veterinary Food Conspiracy?

Today's post was stimulated by a recent email from Kevin.
I've always been told that corn is bad for cats and as a good daddy I want nothing but the best for my furkids as they are my babies and part of my life. My Vet of Six years nows put one of my boys on Hills Science Diet Prescription for urinary tract issues with struvite crystals in his urine. I've read their label and corn gluten meal is the second ingredient after brewers rice and the protein from chicken is like 5th or 6th on list. I don't feel comfortable with feeding my boys this food but my Vet who I believe has sold out to Hills as.she carries nothing but Hills products says that she's had good results with this food from other clients that she's had on this food. It also states on the bag that it is clinically tested to dissolve struvite stones and crystals. Marketing hype I imagine but if it works my boys will be much better off as I don't have 3 to 4 thousand dollars to throw at a blockage including hospital stays and surgery and such and would likely have to say goodbye to my boy. Would you say that this is a good formula to try being that you've had first hand experience with urinary tract issues with cats and dogs I presume being a Vet and all. If you could take the time to answer my questions I would be most appreciated by my boys as well I myself. I have one other choice of food that my boy likes and its by Royal Canin Urinary so and he liked the samples that this other Vet gave him last week when his regular Vet was all booked up I was referred to this other Vet and this is the food that both the Lady Vet and the guy Vet recommended for him. Don't know if you've had any experience with Royal Canin brand food but Chion liked it and his other brothers like it as well and that's what counts with me.

Let me begin by once again speaking against the issue of corn being bad.  CORN IS NOT BAD.  It is NOT filler, it IS digestible, and both dogs and cats DO get benefit from the protein in it.  Seriously!  Years ago some people started espousing the idea that corn was a horrible ingredient, and that has taken hold in the collective consciousness of the American pet owner.  Some food companies have continued to perpetuate this myth (Blue Buffalo, I'm looking at you!).  It is a complete fallacy and there is no scientific basis to that belief that I can find.  In fact, I can find quite a bit of evidence to the contrary.

Here's some specific data from Small Animal Clinical Nutrition, 5th Edition, Hand et al, 2010. 

Protein Digestibility, Dogs
Beef and bone meal--82.4% (25% crude protein in food)
Chicken and chicken by-product meal--85.1% (33% crude protein in food)
Lamb meal--79.7% (20% crude protein in food)
Poultry by-product meal--80.1% (20% crude protein in food)
Beef, fresh--89.8% (20% crude protein in food)
Corn gluten meal--84.7% if 15% crude protein in food; 87.8% if 20% crude protein in food; 90.3% if 30% crude protein in food

Protein Digestibility, Cats
Fish meal--78%
Meat meal--91%
Chicken and chicken by-product--83-88% (different studies represented)
Chicken meal--86%
Corn gluten meal--70-86% (different studies represented)

You can clearly see that the protein in corn gluten meal is just as digestible as in various meat sources, and even more than some of them.  Corn meal absolutely IS digestible! 

From the same text a table summarizes protein quality of common pet food ingredients (Table 5-17 if you want to find a copy of this book).  Corn gluten meal is listed as "good" quality, the same as beef, lamb, pork, chicken, liver, fish meal, meat and bone meal, and lamb meal.  Corn meal IS good quality protein!

I'm not going to take the time to write down many studies referenced in these tables,  but there are around a dozen of them from multiple scientific journals and covering time periods from the 1980s through the early 2000s.  All of the studies that lead to this data are peer-reviewed and accepted by the scientific community and veterinary nutritionists.  There is NO reason why corn gluten meal should not be used in pet foods or why it should be considered inferior to animal protein sources.  I challenge anyone who thinks that corn gluten is a poor protein choice to present a similar list of scientific studies proving their point of view.  I'm sure that you'll get many opinions, but without true scientific studies and data.

Okay, so now on to the next concern...selling out.

Currently there are four major companies making therapeutic diets for pets in the US:  Hill's Science Diet, Royal Canin, Purina, and Eukanuba/Iams.  All of them have their pros and cons and while I don't think any of them are "bad", I do have personal preferences.  Those preferences are based on experience, and I'm sure that other vets have great experience with foods I don't favor.  The bottom line is that all of these companies put a ton of money into research on the quality and efficacy of their foods, and I have no problems with any of them.  Also, all of the companies have comparable diets for different conditions.  For example, each of these companies makes diets for gastrointestinal disorders, kidney disease, and diabetes.  While the forumulations and methods of treatment will vary somewhat, they all do the same basic thing.

A vet has to pay to stock food in their practice, and if the food doesn't sell it comes out of their pocket.  A vet simply doesn't have the space or money to stock food from each of these companies.  Some vets may stock two companies, possibly because they prefer one company for treatment of certain disorders but another company for different illnesses.  But it's impossible for a vet to stock all of them and give people the choices.  Therefore most vets chose a single manufacturer to sell.  That doesn't mean that they've "sold out".  They just have to make a practical, realistic decision as a business owner, and they chose a food that they believe is high quality, will treat necessary illnesses, and be cost-effective to them and the client.  Hill's Science Diet was one of the first companies to make therapeutic diets, and they're still the biggest and most well known, so it's not surprising that a vet would chose them over the other brands.

As an aside, I personally prefer the Royal Canin diets for most disorders.  I base that on personal experience with using the foods compared to Hill's, palatability, their high involvement in nutritional research across the world, and their strong ethics, especially regarding research animals.  I do really like Hill's Metabolic diet for weight loss and overall think they have high quality foods.  I just lean more towards Royal Canin as a personal choice but wouldn't at all advocate against Hill's.

Now that I've spent a lot of time on generalities, let me specifically address Kevin's concerns.  I absolutely and strongly believe that Hill's urinary diets do what they say they will do.  Their C/D and S/D are good foods and will do what the vet says they will.  As I said before, I personally prefer Royal Canin Urinary S/O for these conditions, but honestly it's a matter of degrees as opposed to Royal Canin being significantly better.

Kevin, I hope that answers your questions!


  1. And Royal Canin Satiety formula also has an S/O index, making it ideal for overweight, urinary-blocked cats!

    Blue buffalo and raw diets are some of my pet peeves :(
    Katie Johnson, DVM

    1. Explain your reasons for your "peeves"

  2. corn is bad for all animals. It can not be digested. This is why when eaten it comes back out in the same form it is eaten. Dogs and cats are especially unable to digest it. A meat based diet is all they need. Raw is better for them in so many ways. Animals on a raw diet have cleaner teeth, leaner frame, Have healthier organs and digestive tract.

  3. You're actually making a common mistake. What you are thinking of is whole corn kernels. These are NOT in pet foods. The ingredient in pet foods are corn gluten meal, which removes the indigestible outer part of the kernel. Also, you are completely ignoring established science by saying that animals cannot digest this material. Did you read the data I presented above? This is proven science. I challenge you to refute that data with actual science rather than opinion. By saying that dogs and cats can't digest and utilize corn you are going against every board-certified veterinary nutritional specialist. So you're basically saying that you don't believe science and experts who know far more about this topic than you or I.

    1. This science is backed by companies that are trying to sell a product. Cats and dogs are carnivores. in the wild (like they were created before man domesticated them) they ate an exclusive meat diet. As do wild animals still do. this is what they were created to eat. to say that corn in any form is good form them goes against how they were designed to eat. And how they have evolved to eat for thousands of years. Take for instance the sled dogs and race dogs. they are feed a strict raw food diet and they are well balanced and healthy.

    2. Actually, it is well established that domesticated dogs and wolves are genetically different, including several genes that allow dogs to handle carbohydrates that wolves can't. Dogs are NOT.....I repeat, are absolutely NOT the same as wolves when it comes to their digestive tract and ability to handle meats. Also, just because an animal doesn't eat something in the wild doesn't mean that they can't survive well off it in captivity.

      Sunshinerinker, please share peer reviewed scientific studies that shows data contrary to what I have presented. If you feel that what I've shared is part of a big conspiracy and that this science is inherently biased, please share comparable studies that disprove what I have presented.

  4. Neither Hills nor Royal Canin seem to have Vitamin K3 (mendione) in them, which is a relief but my only concern with Royal Canin is the BHA.

    Living in Asia, instinct tells me that grain isn't that bad either, I mean domesticated cats and dogs in this region have eaten grain including rice for hundreds of years before pet food was invented, and actually I am a bit doubtful about the non-grain super high protein pet foods when it comes to domestic pets that live in big cities. Even in the wild do wild animals get to eat their high protein pray every single day? My pets are shifting slowly towards kibble with human grade toppings -- nothing special just putting aside few ingredients before cooking for humans and it seems to be working OK.


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