Dog Food Protein, Why Should I Care? Pt 1
Tasty Tuesday is about celebrating ‘good food’. Good food can mean many different things. To SlimDoggy, our goal is to help our friends understand the essentials of quality food, food you want to feed your pets every day. What makes it ‘good’ vs. what makes it not so good. We don’t want to be the food police for dogs, we just want to share some of what we’ve learned in the process of building our App and our food database.
Last week we established that dogs require a diet high in protein from high quality protein sources. Proteins should form the base of a good diet for your dog. Today we will focus on protein: why it is essential, comparisons of different proteins, and how to tell if your dogs food has a high protein content.
The Building Blocks
Proteins are necessary for growth and development and key to the creation and maintenance of the muscular and skeletal structures as well as the immune system. It is not protein exactly that is needed but the amino acids contained in the protein that are critical. Proteins consumed in the diet are broken down into the building block amino acids by the digestive system, so the body can use them to build, rebuild or replace cells in the body.
Dog’s require 22 amino acids, 10 of which, called “essential’, must come from dietary sources. The 10 essential amino acids are: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Proteins can be evaluated in several ways including their biological value and their digestibility.
Biological value compares the nutritional worth, or completeness, of different protein ingredients. It measures a protein’s ability to supply amino acids, especially the 10 essentials, and to supply them in the appropriate proportions. Below are the biological value ratings for some proteins. You will notice immediately that meat and fish have higher values than plant and grain proteins.
This is the measure of the body’s ability to break down and digest the protein for use in cellular functions. Dogs have short intestinal tracks and thus plant proteins are less digestible than meat proteins. T.J. Dunn, Jr. DVM, has published this data on digestibility of common dog food proteins.
In short, unless there is an underlying medical reason, dogs should be fed a diet with meat or fish as the primary protein source.
How Much Protein is in My Dog’s Food?
The Association of American Feed Control Officials (AAFCO) publishes nutritional minimums and standards for dog foods based on the life stage of the dog. The table below shows the AAFCO protein and fat minimums.
To see how your dog food stacks up against the AAFCO guidelines, you need to know how to read the “Guaranteed Analysis” section of the food label. The key to understanding the guaranteed analysis section of the label is to convert all the values to a ‘dry matter’ basis. Dry matter (DM) analysis simply adjusts for the moisture content of a food, and is especially important when looking at canned (wet) food. Below is an example. The normal food label will list the first two columns- the nutrient type and the associated percentages on an ‘as fed’ basis (which means including the moisture content).
We have added another column to the table showing the DM values. To calculate the DM basis of protein (and other macro nutrients), you first need to determine how much of the food is not moisture and use this to rescale the nutrient percentages. In the example above, 78% of the food is moisture so 22% is dry. Use the reported (as fed) protein percentage and divide that by the dry percentage to determine the true protein content. In this example, we would divide 8%/22% = 36%. Thus, this food is 36% protein which obviously exceeds the AAFCO minimums.
Limitations of the DM Analysis
Using the DM analysis is a quick way to determine the relative protein amount in your dog’s food. Unfortunately, it doesn’t tell the entire story because we can’t tell the protein’s biological value nor its digestibility. Not sure what to do? Stick with meat and fish based protein sources to ensure that your dog is getting and utilizing adequate protein and amino acids.
Next week, we will continue our discussion of proteins and will examine the difference between common meat and fish based protein sources.