# What do you make of this!



## Tracy (Aug 11, 2012)

Various studies have shown that reducing levels of protein in the diet can reduce aggression. Evidence shows that high dietary protein levels significantly reduce the amount of tryptophan reaching the brain for the manufacture of serotonin - the 'feel good chemical'. Serotonin serves many important functions such as the management of stress, impulse control and mood regulation. When levels are low, dogs may become more irritable and aggresive. In cases where dogs demonstrate such tendencies, we usually recommend to clients that they feed a diet which contrains less than 18% protein.

The people who wrote this are so called dog behaviourists in our area.


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## Sprocket (Oct 4, 2011)

I'm still waiting for my pitbull to get the taste of blood and become a human killer maniac. Now he needs less protein or he will become aggressive? Taste of blood...plus aggression...Should I prepare for this change in attitude? :tongue:


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## DaViking (Sep 27, 2011)

Tracy said:


> Various studies have shown that reducing levels of protein in the diet can reduce aggression. Evidence shows that high dietary protein levels significantly reduce the amount of tryptophan reaching the brain for the manufacture of serotonin - the 'feel good chemical'. Serotonin serves many important functions such as the management of stress, impulse control and mood regulation. When levels are low, dogs may become more irritable and aggresive. In cases where dogs demonstrate such tendencies, we usually recommend to clients that they feed a diet which contrains less than 18% protein.
> 
> The people who wrote this are so called dog behaviourists in our area.


Do you have a link?


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## Tracy (Aug 11, 2012)

No link. I just opened up my local paper and read this. I've never heard of anything like it. 

These people write a blogg every month on dog training and behaviour. As far as training and behaviour go, I would never use there methods, especially with reactive dogs, they're very harsh. I'm just wondering where they're basing this information on and if anyone else has ever seen actual evidence of this.


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## Tracy (Aug 11, 2012)

Sprocket said:


> I'm still waiting for my pitbull to get the taste of blood and become a human killer maniac. Now he needs less protein or he will become aggressive? Taste of blood...plus aggression...Should I prepare for this change in attitude? :tongue:


He he. I'm watching mine too. Waiting for them to turn.


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## DaViking (Sep 27, 2011)

Tracy said:


> No link. I just opened up my local paper and read this. I've never heard of anything like it.
> 
> These people write a blogg every month on dog training and behaviour. As far as training and behaviour go, I would never use there methods, especially with reactive dogs, they're very harsh. I'm just wondering where they're basing this information on and if anyone else has ever seen actual evidence of this.


I'd love to see their sources. This science is called nutrigenomics and is in it's infancy.

Quote from Dr. Cheryl Morris
"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."
Evolve Animal Services: Back to the idea of Nature versus Nurture


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## Tracy (Aug 11, 2012)

Very interesting.

I'll try and e-mail them and ask where they're basing their information from.


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## Tracy (Aug 11, 2012)

This was their reply.

Hi Tracy,


Martin has passed on your request to me since as a scientist, I take a particular interest in researching the theory behind these ideas. 

Thank you for your interest in our blog. Whilst we enjoy writing it, we are very much limited by space and therefore cannot go into much detail or give references. Also we have to make it interesting to those who are neither scientists nor dog trainers/behaviourists. However we are always very happy to provide more details to those in the profession.

Various studies have shown that reducing levels of protein in the diet can reduce aggression. Mugford (1987) observed a decrease in aggressive behaviour of a group of golden retrievers after they were placed on a low protein diet. Then Dodman et al (1996) demonstrated that reducing dietary protein levels exerted a beneficial effect on dogs exhibiting territory related aggression with fear. 
The strongest evidence however comes from basic brain research. Studies have shown that high dietary protein levels significantly reduce the amount of tryptophan reaching the brain for the manufacture of serotonin – the “feel good” chemical (Spring, 1986: Christensen, 1996). This may seem paradoxical since tryptophan is an amino acid component of proteins. However the effect is due to a transport mechanism responsible for the selective transfer of nutrients from the blood into the brain. When the blood contains high levels of protein, other relatively more abundant circulating amino acids compete with tryptophan for a limited number of transport molecules thereby impeding the transport of tryptophan into the brain (Lindsay, 2001). In support of this, De Napoli et al (2000) have reported that supplementation of the diet with tryptophan may significantly modulate aggressive behaviour. 
Serotonin serves many important functions such as the management of stress, impulse control and mood regulation. When levels are low, dogs may become more irritable and aggressive.
References:
Christensen, L (1996) Diet-behaviour relationships: Focus on depression. Washington DC, American Psychological Association
De Napoli, J.S., Dodman, N.H., Shuster, L., Rand, W.M. & Gross, KI (2000) Effect of dietary protein content and tryptophan supplementation on dominance aggression, territorial aggression and hyperactivity in dogs. JAVMA, 217, 504-508.
Dodman, N.H., Reisner, I., Shuster, I. et al (1996) Effect of dietary protein content on behaviour in dogs. JAVMA, 208, 376-379.
Lindsay, S.R. (2001)Handbook of Applied Dog Behaviour and Training, Vol 2, USA, Blackwell
Mugford, R.A. (1987) The influence of nutrition on canine behaviour. J Small Anim Pract. 28, 1046-1085.
Spring, B. (1986) Effects of food and nutrients on the behaviour of normal individuals. In Wurtmann, R.J. & Wurtmann, J.J. (Eds) Nutrition and the Brain, 7, 1-47.
If you look at the protein levels on dried dog foods you will find that many are as high as 23-26%. Martin and I both use Burns for our own dogs because this is a holistic food with no additives, wheat or dairy products and contains only 18% protein. Tinned dog food only contains about 6% protein because of course it is largely water. Neither of us feed bones since we feel that there is too much danger of perforation. Also, when I have done so in the past, it has caused the dogs to suffer from diarrhoea. When wolves eat bones, they do so together with fur, skin etc which protects the bone as it passes through the digestive tract. This is, of course a personal choice and I am sure many will disagree. 
I hope this helps. Please don’t hesitate to contact us again if you require any further information.

From: Martin Gleadow


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## DaViking (Sep 27, 2011)

Thanks Tracy.
Well, other studies show higher protein diets to be beneficial for dogs with aggression issues and I don't think Dr. Cheryl Morris is a person who make claims without any references. Maybe I'll email her to ask if she have the links to those studies. Personally I don't know what to make of it until I see more from both sides.

On a side note; They feed a food with only 18% protein? That sounds too little to me. Dogs on a maintenance diet need roughly 2g of protein per kilogram bodyweight (1.66g per NRC). If the dog is active, get a lot of exercise and/or training you can add 25% to that. Using my own JRTx as an example it amounts to 22.5g protein per day. After normalizing their 18% protein food to dry matter and adjusting for a ~ 85% to 90% protein digestibility we end up at around 15g of protein. 7.5g less than he needs per day (4g less @1.66g protein). Not adjusted for individual metabolism.


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## Tracy (Aug 11, 2012)

It's very interesting. 

The more I learn, the more I don't know.:tongue1:


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## Rvent (Apr 15, 2012)

Sprocket said:


> I'm still waiting for my pitbull to get the taste of blood and become a human killer maniac. Now he needs less protein or he will become aggressive? Taste of blood...plus aggression...Should I prepare for this change in attitude?
> 
> Me too, the only aggressive part of my pit bulls are their tongue and tails!!!


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## zontee (Oct 12, 2012)

i have always heard its only an issue when the protien is cooked because of how the body uses it.


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