Understanding Canine Nutrition (Part I)

This article appeared in the Bagpipes in January, 2006.

There are seven basic building blocks of nutrition that should be present in the food that your dog eats and they are; water, protein, carbohydrate, fat, fiber, vitamins and minerals. Each has its own purpose and function, but does not work alone. All of these elements are required in different, yet specific amounts, and this is what is referred to as a “well balanced diet”.

Water: The average adult dog’s body is approximately two-thirds water! Water is required for the normal function of every cell in the body; and is needed for respiration, digestion, metabolism, and elimination. Water keeps everything in balance, and the amount that is lost each day must be replaced.

Protein: After water, protein is the most abundant substance in the dog’s body. Why is protein so important? Proteins act as the building blocks for hair, nails, skin, muscle, tendons, cartilage and connective tissue. They are also vital to the immune system, digestive system and help to facilitate hormone production. Proteins can be complete or incomplete. Proteins such as lean meat, eggs and milk are called complete proteins since they contain the various amino acids in appropriate proportions to make the proteins needed by the body. Sources of protein such as soybeans, wheat and corn are called incomplete proteins since they do not contain an appropriately balanced ratio of the various amino acids. These protein sources have to be combined to come up with the correct balance to meet the dog’s needs. A diet deficient in protein can result in growth (skeletal) abnormalities, problems with the skin and coat, a weakened immune system, lack of energy, and even depression. Performance dogs and those recuperating from illness or injury may benefit from additional protein. Protein can be used to make energy, and any excess will be stored as fat. Excess protein may be difficult for a dog to metabolize if it has kidney failure; however, contrary to popular belief, these dogs require a high quality protein in their diets. It is advisable that your dog obtain its protein from a variety of sources, since eggs are the only 100% complete protein. Sources of protein include: Beef, chicken, turkey, lamb, organ meats, eggs, milk and cheese*, fish, and other meat sources.

Carbohydrates: Carbohydrates can also provide an energy source for the body. The carbohydrate family consists of simple and complex carbohydrates. Simple carbohydrates are sugars which are easily digested by the body and converted into an energy source called glucose. Glucose is a fuel for muscles, as well as the brain and nervous system. Excessive glucose is converted to a substance called glycogen, which is stored in the liver and muscles for future use. Complex carbohydrates are starches and cellulose. These are not digested easily by the dog’s body; and cellulose serves the same purpose as fiber. Dogs need very little carbohydrate in their diet, as little as 5% is sufficient. Commercial dog foods often contain lots of carbohydrates, since they're a less expensive source of energy than protein or fat, and because kibble will not hold together unless it contains 60% carbohydrates. Too little carbohydrate, and the body will tap into its reserve of protein. This may result in weight loss, fatigue or lack of energy, poor circulation, and in extreme cases a breakdown of essential body protein (a rare occurrence in dogs). Sources of carbohydrates include:
Corn, rice, oats, barley, potatoes, wheat, fruits, and vegetables

Fats: Fat has somehow earned a bad reputation, so let me set the record straight! Fat is not a bad thing, but too much, or the wrong type of fat, can be detrimental to a healthy body. Fats are necessary for normal growth, healthy blood, normal kidney function, shiny coat and supple skin. Fatty layers under the skin serve as insulation. Fat is a highly concentrated source of energy, supplying more than twice the energy of protein or carbohydrate. Essential fatty acids (EFAs) must be available in the diet, as the body cannot manufacture them. They are important as anti-oxidants and for maintaining a healthy immune system. Even as you read this, new and vital roles for EFAs are being discovered. Fat transports fat-soluble vitamins into the body. Fat may also make food taste better, stimulating the appetite of finicky eaters,, and may help your dog feel fuller with less food. An excess of fat in the diet will lead to obesity and related disorders. An excessive intake of fat will slow down the digestive process, resulting in nausea, vomiting and diarrhea. Signs of a diet deficient in fat may be dry, flaky skin or a dull coat. In some cases, diseases of the liver, pancreatitis, or chronic digestive disorders may be the result of a rare fatty acid deficiency. Sources of fat include: Animal fat, fish oil, and vegetable oils

Fiber: Fiber is the part of food that is not digested by the dog’s body. Fiber in the diet is good for gastrointestinal health, and may help some dogs keep their weight. In fact, fiber will help treat both diarrhea and constipation. Fiber absorbs extra water in diarrheic stools, and it helps hold onto water, which prevents constipation. Some fiber is broken down in the intestine into fatty acids. These fatty acids will aid in preventing the overgrowth of harmful bacteria. Low calorie commercial dog food normally have an increased amount of fiber because the dog can eat more, feel full, and yet consume fewer calories. Too much fiber can interfere with the absorption of certain nutrients, cause loose stools and frequent bowel movements. Sources of fiber include: Almost all carbohydrate sources contain some fiber. Some of the most common sources of fiber in commercial pet foods include rice hull, corn and corn by-products, soybean hulls, beet pulp, bran, peanut hulls and pectin.

Vitamins: Vitamins, discovered in 1910, are organic substances found in plants and animals. Vitamins and enzymes work together to perform a variety of functions including digestion, metabolism, growth, reproduction and oxidation. In simple terms, vitamins are responsible for releasing nutrients from food sources and are needed for a myriad of chemical reactions throughout the body. The fat-soluble vitamins (A, D, K, and E) can be stored by the body in the liver and fatty tissues. The water-soluble vitamins (B and C), cannot be stored by the body and any excess is excreted by the body. The fact that a vitamin can be both essential and harmful may seem surprising, but the same is true of most nutrients. The effect of every substance depends on its “dose”. Common sources of vitamins are listed below.

Minerals: Minerals are present, to some extent, in the tissues of all living things. They make up your dog’s teeth, bones, muscles, blood and nerves. Minerals work with enzymes, with vitamins, and with each other. Some of the minerals essential to your dog’s health are; Calcium, Chloride, Copper, Iodine, Iron, Magnesium, Manganese, Phosphorus, Potassium, Selenium, Sodium, Sulfur and Zinc. It’s important to keep in mind that no single vitamin or mineral functions alone; each has its own place in the system, but each is also dependent on the others. An excess of one mineral may actually cause a deficiency of another. If you plan on supplementing your dog’s diet, please seek the advice of your veterinarian, and remember to keep all the nutrients balanced. Common sources of minerals are listed below.

In order to properly use the food we feed them, dogs need to produce adequate amounts of the appropriate enzymes for digestion. Enzymes are complex proteins produced by the body itself, and they work together with vitamins to facilitate chemical reactions. The four basic digestive enzymes for dogs are: proteases (break down protein), amylases (break down and help digest carbohydrates), lipases (break down fat) and cellulases (break down vegetable matter). These enzymes break down the food the dog eats, making the food’s nutrients available for the body to use. Any enzymes in the diet are broken down to their component amino acids, just as other proteins are.

Note that as you dog’s life changes, the diet may need to change as well to meet different nutritional requirements. So whether you feed your Beardie a raw diet, or a commercially prepared diet, the important thing to remember is that the diet provides the nutrients the dog needs to function optimally and maintain an appropriate weight. If you feed raw, you are responsible for providing your dog with all the essential nutrients (not too difficult, as nature provides them “prepackaged” in most instances. If you feed a commercially prepared pet food, please read the label, and be aware what goes into that bag before you feed it to your dog. Next month, we’ll learn about those ingredients listed on the label of your Beardie’s food. Bone appetite!

*Most adult dogs do not digest dairy products well. Yogurt and kefir (from raw cultures) are usually well tolerated and can be helpful for restoring normal gastrointestinal bacteria, especially when the “good bacteria” are eliminated following treatment with antibiotics.

Copyright © 2007 by Maryann Szalka. All Rights Reserved. Contact Maryann for reprint permission.