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Thursday, February 11, 2016

Clarifying Cat Nutrition

I recently received an email from George with some questions about cat foods and cat nutrition.  At the same time I just this week read an article on the issue of carbohydrates in cats, so all of this ties together quite well.  If this is your first time reading one of my blog posts on nutrition I would highly encourage you to go to the search box on the top left of the blog and put in "nutrition".  I've written quite a lot on this subject over the years and you'll find a lot of answers about corn, byproducts, grain-free, etc. in these older posts.  I'll try to avoid repeating myself too much in today's post.
I'll break George's email into sections and respond to each part individually.  I am also going to be quoting the article I read, which is by Cailin Heinze, MS, VMD, DACVN (Diplomate of the American College of Veterinary Nutrition), an assistant professor of nutrition at Tufts University.  Her opinion weighs stronger than mine because of her specialty in nutrition, so if you don't believe me, maybe you will believe her.
Hello Chris i read your article regarding cat food. You say that these nutritionist tell you that Hills, Purina, Iams, and royal canin are what they feed there cats. That is amazing to me. My research tells me that firstly dry foods have no real moisture content. So cat are already semi dehydrated due to there lack of thirst drive.
Yes, board-certified veterinary nutritional specialists routinely recommend these foods and feed them to their own pets.  It is also true that dry foods have a lower moisture content than canned or soft foods.  However, that doesn't mean that there is no moisture.  A dry food may have 10-20% moisture by volume while a canned food may have 80%.  Yes, a considerable difference, but not a harmful one.  It is true that in the case of urinary disease we want as much fluid passing through the kidneys and bladder as possible, so we recommend canned foods for these pets.  But dry food is fine for most other cats.  Also, cats are NOT semi-dehydrated.  Trust me on this as a vet, a dehydrated cat is a sick cat, and a healthy cat should never be dehydrated at all (even "semi-dehydrated"...which is a term that we don't use in medicine and has no real definition).  Cats also very much have a "thirst drive".  When they are thirsty they will drink.  You may not notice it as much as with dogs because cats are more likely to eat and drink privately.  Their original ancestors were desert cats, so our modern house cat is virtually a desert animal.  Their kidneys are very efficient so a cat has to drink less than a dog of the same size.
From Dr. Heinze's article:  "I never criticize owners for feeding dry diets...Some health conditions will dictate that a cat ideally be fed a canned diet later in life, so it's best to have flexibility."
More from George:
Then take into consideration that the first ingredients of these foods are 1. poultry by product, corn meal, corn gluten meal , brewers rice, soy fiber, animal fat. The first ingredient should be turkey, chicken, venison, duck or what ever the protein source is. Am i wrong here?
No offense, George, but unfortunately you are wrong.  The first listed ingredient does not mean that it carries the most protein or other nutrients.  Ingredients are listed by pre-cooked weight, not by nutritional quality or density.  So an ingredient is first just because it weighs more, not because it's "better".  It is very possible for a manufacturer to manipulate the ingredients so that "real meat is first", even if it doesn't give the most protein.  I wrote extensively about it this past December so I'll link you to that post.  Click on that link for a much longer explanation as to why the first ingredient is somewhat irrelevant.
Please educate me on this because i am spending alot of money on these brand name foods. My disagreement with what you say is this. Cats and dogs do not need gluten, soy, corns, wheats, etc in there foods. And it has been debated that these grains are harmfull.
Unfortunately there is a ton of misinformation in these sentences.  There is absolutely, positively NOTHING wrong with gluten, soy, corn, wheat, etc. in dog and cat food!
Dr. Heinze:  "Misconceptions about cats and carbs stem from the popular belief that, since cats are obligate carnivores and don't really eat carbohydrates in the wild, they shouldn't eat them, period.  A healthy cat doesn't require carbs, but can digest them." 
There are a lot of great reasons why these ingredients are found in pet foods.  Dogs and cats absolutely have an ability to digest and utilize carbohydrates from many different sources.  Here's a link to a post I wrote in January of last year
The people debating about whether or not grains are harmful are not the nutritional specialists.  I have never read or heard a veterinary nutritionist say anything against grains.  The recommendations for grain-free diets have to do with fad and misinformation, and have nothing to do with scientific facts. 
Dr. Heinze:  "Another misperception among owners is that grain-free diets are inherently healthier than diets with grains.  Grain-free does not equal carbohydrate-free.  Ingredients substituted for grain, such as peas, tapioca, lentils or potatoes, are no more part of a 'wild' cat diet than grains.  However, it is likely that the type of carbohydrate matters.  Tapioca starch is a very simple carbohydrate, not too different from glucose.  Whole grains and complex carbohydrates are likely better choices, because they are less likely to trigger dramatic changes in blood glucose."
Wow, grains may actually be beneficial to cats!  Maybe we should listen to a board-certified nutritionist. 
Dr. Heinze continues:  "Diets both with and without grains can be very healthful.  Corn, for instance, is highly nutrition and not a so-called dietary 'filler'.  If clients have concerns about feeding their cats diets that contain grain along with meat protein, I remind them that grains provide a high-quality source of protein....On a related note, gluten is a big bad word these days.  If people are forgoing gluten themselves, it's very hard to convince them in most cases there's no real benefit to feeding their pet a gluten-free diet.  I emphasize that feeding too many calories and allowing cats to become obese is the real cause of health problems in cats, not feeding gluten."
I don't know about you, but reading Dr. Heinze's words seems to be pretty convincing against the fad of grain-free, gluten-free diets.  Which brings us to the last part of George's email.
This is why every cat food company has jumped onto the Grain Free Foods.
Do you want to know why pet food companies have started making grain-free foods?  Because customers want them!  It's supply and demand, nothing more.  Some people without any scientific basis started talking about grain-free foods, and it somehow became wide-spread among pet owners.  Pet food companies are out to make money and sell foods.  If clients want a particular flavor, ingredients, shape, and so on, they'll absolutely make that food as a way to sell product.  As more and more people are "convinced" that their pets should eat grain-free diets the food manufacturers are merely making products to meet that demand.  Customers are willing to pay a premium price for these newer diets, even though there is absolutely no evidence that they are nutritionally better than other foods.  The plethora of grain-free diets is not about science or nutrition, it's about meeting customer demand.  Unfortunately those customers are misinformed.  And have you noticed that while there are many grain-free diets on the market, the companies haven't stopped making diets containing grains?
If you really want to know why nutritional specialists recommend brands like Iams, Purina, Science Diet, and Royal Canin, you can call these companies and ask them yourself.  A few months ago during a nutrition series I listed questions that nutritionists use to assess a company's ability to produce high quality foods.  None of that information is found anywhere on the labels!  These questions are agreed on by most veterinary nutritionists and are what they consider when making food brand recommendations.
George, I hope this has been enlightening and informative.  Hopefully you can see a different perspective from what you have learned so far, and know a bit more why specialists recommend these foods.  If you still disagree, then you can reach out to Dr. Heinze and other members of the nutrition specialty, as all of my information comes from them.