What's better...ancestral or natural history?

The idea of ancestral diets is an interesting one for me.  I hear it when people say they want to feed raw diets..."I want to feed a more ancestral diet" and "dogs and cats are carnivores", and I see it all over the marketing of pet foods, particularly grain-free foods.  What does that mean to everyone?

In reality there are more than 260 mammal species listed under the order Carnivora.  Yes, that list includes the cat and the dog, and closest taxonomic ancestors to both, the European wildcat and the wolf.  However, it also includes otters, civets, seals, and bears.  That last category is one of my very favorites to discuss in terms of comparative nutrition because it includes the Giant panda.  Oh yes, indeed they are carnivores in every sense of the word.  Anatomically they have short digestive tracts and limited ability to ferment fiber...surprised? The difference is that panda's have evolved and adapted to their environment and have lower requirements for protein and energy compared to other carnivorous species.  If' you've ever seen panda poo, you've noticed that it looks just like panda food.  They must consume gigantic amounts of bamboo just to meet those low energy and protein requirements (also why they don't move a whole lot).  If I wanted to feed a panda like their other relatives (carnivores), I'd likely produce very fat pandas with metabolic issues.  While we could feed pandas the same diets we feed other bears, we certainly do not...they are fed primarily bamboo as most of you already guessed.  Why then do we constantly focus on wanting to feed dogs like wolves and cats like tigers?

When it comes to felids, I won't argue with anyone that chooses to feed a strictly raw meat or whole prey based diet.  Cats have not evolved to be anything other than obligate carnivores.  Their protein requirement is twice that of dogs and they require vitamins that are unique to the consumption of organ meats that other carnivores do not require in the same high concentrations (taurine, vitamins A, D, and niacin). 

Canids on the other hand are not obligate carnivores...except one species.  I love discussing canid species as their variation in diet and natural history is nothing short of amazing.  Consider the little bat eared fox that consumes almost exclusively insects, or the maned wolf whose diet during portions of the year is made up of nearly 70% plant material from a fruit in the same family as the tomato.  Then, consider the only obligate carnivore canid...the African hunting dog (pictured below thanks to Omaha Zoo keeper Emily Wiley). These incredibly beautiful canids have never been observed consuming anything other than meat.  Most people aren't surprised when I tell them that I can't feed these species the exact same diet at the zoo and indeed their captive diets are not at all similar.  Maned wolves in captivity thrive on a diet that most of you would consider tragically high in carbohydrates and grains.  I must consider each individual species' natural history when I formulate diets. 



So, why on Earth do we seem to forget to consider that in respect to the species that live in our homes? Now, don't take this wrong, I'm not by any means saying that you should feed your dogs a high carbohydrate diet.  I believe quite the contrary.  The dog evolved because of us and the food we consumed. They thrived and became what they are today because we fed them a huge variety of dietary ingredients just like we fed ourselves.  It wasn't until the last century or so that we started making highly processed specialized dog foods and then deciding that only one food was appropriate (that idea we can thank the petfood industry for).  I don't believe that one food is appropriate for pets and I feel we should provide them with variety that their natural history dictates.  I know I've said it before but my dogs would be hard pressed to recall their diet over the last week because of the variety.  I do feed rotated kibbles, canned foods, raw, fresh fruits and veggies, some grains (mostly oatmeal), eggs, and fish.  The beauty of this is the result that I can feed them just about anything and not have to worry about GI issues.  Sadly, our society has been so conditioned to only feed our pets one diet that we've prevented most of our pets from developing the ability to cope with the variety their natural history tells us they should have.   

So, is it really that we want to feed our pets an ancestral diet or is it more that we want to feed them a more natural diet based on their natural history? To me, that makes a whole lot more sense. 

Feeding the Seniors in the House

Sparky, he's the dog that started my addiction to agility and dog sports.  He's the one that learned how to play flyball when he didn't even think balls were all that cool.  He's my 13 year old Rat Terrier that moved with me from New Mexico, survived grad school, taught me how to train, saw me through a divorce, new career and a new marriage...he is my best friend.  I am faced everyday with the fact that he's getting older and he's definitely now considered a "senior" dog, something I know many of you reading this also face daily.

This week I've been putting the final touches on an invited manuscript summarizing a symposia I chaired in July at a National conference.  The symposia was about managing geriatric animals.  I thought it was a good topic and one that many people often ask me about.  What should I feed my senior animal?

The aging process can impact diet palatability and intake from physical changes that alter animal's senses, particularly taste and smell.  In addition, as animals reach geriatric age, physiological changes occur that can alter nutrient requirements.  Typically, energy requirements decrease; however, essential fatty acid and protein requirements often increase.  This, coupled with reductions in digestive efficiency, result in seniors requiring bioavailable and digestible diets based with very high quality ingredients.

There are as many opinions about feeding seniors as there are diets. Some say feed more protein, some say less, some say more fat, some say less fat.  As with humans, you must feed the animal and look at them each as individuals.  Not all seniors should be treated the same.  I suggest bloodwork annually to monitor kidney and liver function in senior animals.  This can really help catch conditions early enough that specialized diets can truly support before needing prescription medications.  If seniors are in great condition and there are no indications of health concerns, I am certainly not going to reduce or change the diet.  The only thing I will do is add a digestive enzyme such as Prozyme or Prozyme Plus. 

One of the other nutrients that I've spoken about extensively is water.  Add water to all kibble!  I'm even struggling at the zoo with the amount of water that is included (or not) in feeds we typically feed exotics.  Take for example, herbivores such as giraffe, zebra, antelope, horses, and cows (only because I've mentioned this very issue in carnivores and I'm hopefully driving home a point).  "Wild" diets consist of fresh plant materials that are 70% or more water.  We have for decades focused animal husbandry on concentrating those nutrients into dried forages such as hay and dried pelleted grains and rations.  I can almost with 100% certainty offer "browse" or fresh plant material to a sick or geriatric herbivore and have them eat.  It certainly makes me wonder why we'd consider feeding and managing our animals on "dry" diets when so much of their natural diet contains much larger concentrations of water.  So the bottomline here is that if you are using kibble diets, add water to them.  If you are worried about dental health then provide abrasives such as bones to chew on and brush teeth.  I have toy dogs that notoriously have crappy teeth so I feel I can have an opinion about this.  I will tell you that feeding kibble did not change their teeth but brushing and bones did. 

In conclusion, I feel that seniors need a high quality, very digestible food until biological markers indicate a concern that needs addressed nutritionally.  In addition to the added water, Sparky also is supplemented with fish oil, Prozyme Plus and Dasuquin.

Back to the idea of Nature versus Nurture

Happy New Year!
It has been too long since my last post but there were a few things that got in the way of my writing.  The AKC Agility Invitational and Christmas come to mind.  Prior to the trip out to Orlando for the Invitational, a few people emailed me the following link asking about my thoughts on the topic.  It's from Patricia McConnell's blog, The Other End of the Leash: http://www.theotherendoftheleash.com/your-dog-has-a-brain-in-his-gut

I always have enjoyed Patricia's writing and still do and was happy to see the topic surface on her blog.  After I read it, my initial reaction was "well, yes, of course emotions are linked to nutrition...how could they not be".  The reality is that nearly every biological system of the body is linked to the digestive tract in some way.  When it comes to the nervous system, one division of the nervous system in particular, the Enteric Nervous System (the topic of the referred to blog post) is responsible for control of the gastrointestinal tract of vertebrate species.  It is this system that automatically stimulates muscles and organs to start contracting (to move food through the gut) and secrete important digestive enzymes and hormones supporting metabolism.  In addition, dozens of neurotransmitters are active through this system.  Several of these neurotransmitters are indeed related to emotions and the one I'll refer to is serotonin (mostly because I feel people are familiar with it). 

Serotonin has been linked to behavior, including aggression, depression and hyperactivity, in many different species including rodents, dogs, humans and primates.  The research in this area is extensive and easy to find.  Biochemically, serotonin is derived from the metabolism of tryptophan, an essential amino acid found in proteins and chocolate (a reason why some of us find comfort in chocolate).  These types of complex interactions between and among nutrients and the nervous system  have given rise to the ideas of "cooling proteins" and "calming proteins".  Unfortunately, this is where research is lacking.  Although there is extensive research linking neurotransmitters to diet, there are many complex levels of these interactions.  The intuitive reaction that people have is to simply provide more dietary tryptophan by increasing protein or supplementing. However, it just isn't that simple.  In some animals, that simplistic idea may work but in others it won't. Why not?

Consumed dietary tryptophan must be converted to serotonin by an enzyme.  If there are reduced levels of this enzyme, then no amount of dietary supplementation of tryptophan can account for that.  In addition,  there are additional complexities in the fact that serotonin must be transported by  proteins (transporters) and the neural messaging is sent via proteins called receptors.   All of these proteins (enzymes, transporters, receptors) are all coded by very specific genes within  specific genomes.  Each of these genes I envision like volume dials.  Environmental factors (including diet) can turn them up (up-regulate) or turn them down (down-regulate)...hence the concept of Nature vs. Nurture?  My very favorite way of looking at this is the metaphor that genetics will load the gun, but environment pulls the trigger.  So in any animal that may have one or more of these genes down-regulated such that the result is less of the enzymes, transporters, or receptors, then serotonin's impact on the brain may be reduced.  These incredible complexities are why we have such conflicting data surrounding the issue of meat based diets on behavior.  Some studies show high protein diets are beneficial for animals with aggression, while others say high carbohydrate diets are better. 

So, what the heck does this all mean? Now that we know the genome of species including humans, dogs and cats, we can now begin to understand how particular nutrients are impacting specific genes of interest such as those involved in tryptophan and serotonin metabolism.  This area of research is known as nutrigenomics and is truly fascinating to me.  In other words, while we all have the same genome, our genetic expression varies.  The amount of tryptophan that my body needs may be vastly different from that of my husband.  We can begin to look more specifically at how individual nutrients are impacting each of these genes.  That's when we'll be able to determine what the real causes of behavior and temperament issues really are...is it a simple lack of dietary tryptophan (not likely) or is it a lack of an enzyme, a transporter, or a receptor.  If we can identify the issue correctly, then we might be able to figure out how to turn that dial back up or down.  It would make an enormous difference in how disease is diagnosed and treated. 

In Patricia McConnell's post, she indicated that probiotics might be useful for the ENS.  Sure! If you recall from my first blog about probiotics, I mentioned that I only use them when the systems are "off-balance".  Being off-balance may not manifest in loose stools and vomiting.  An unbalanced digestive system and enteric nervous system may indeed be observed through behavior problems, lethargy, appetite, etc... Can I say for sure that supplements or probiotics are going to help? No, I can't.  Because our animals (and us) are unique individuals, what works for one may not work for another.  Would I try it? Yes, I would.  Until we can unlock the mysteries of metabolism, there is some degree of anecdotal success that we must appreciate.  Recall, there are dozens of these neurotransmitters, metabolites, and hormones contributing to our overall biochemistry. I didn't even talk about stress hormones such as cortisol and how it impacts the ENS.  It is all of these complex unknowns  that make me appreciate the science of nutrition even more and why you will never hear me say there is "only one way" to feed you or your animals.  We simply don't know or understand them all yet.

Happy New Year!