Nutrition for Dogs: Is your Dog Food Healthy?

Most of us don't remember the times before commercial dog food. However, the use of commercial dog food in the United State is fairly recent. The use of commercial canned and dry dog food did not become popular in the United States until after World War II. Before then, dogs ate whatever was available. Usually, their meals were either table scraps from their owner's tables or cheap cuts of meat from the butcher.

In response to watching sailors throw hard tack to stray dogs, James Spratt of Cincinatti, Ohio, developed the first commercial dog biscuit. Called Spratt's Patent Meat Fibrine Dog Cakes, it was made out of wheat, beet root, vegetables, and beef blood. Shortly thereafter, other companies began offering dog food. While some were endorsed by vetenarians, others even claimed to cure dogs of worms and other diseases. Unfortunately, the increased use of commercial dog food has been accompanied by a decrease in health and longevity. By nature, dogs and cats are carnivores not herbivores.

In the wild, dogs eat primarily protien. An adult dog needs a diet with 18% protien while puppies and lactating dogs need 28% protien. When an animal is weak or sick, they may need even more protien.

When examining the dog food label for the protien content, we look at the guaranteed analysis. However, the guaranteed analysis can be misleading because it is not based on just dry matter but on moisture content too. Consequently, to find the true amount of protien we need to subtract the moisture content. For example, if the guaranteed analysis of crude protien is 21% and the moisture content is 12%, subtract 12% from 100 which gives us a dry matter weight of 88%. Next, divide the guaranteed analysis of crude protien by the dry matter weight: 21% /88% = 24%. Consequently, the dry weight of crude protien is 24%.

One source states estimated that a dog's ancestral dietc was composed of 14% arbohydrates. Nowadays, commercial pet food is composed of 45% to 65% grains or carbohydrates. However, grains are not a natural part of a dog's diet or cats.

Grains are considered a complex carbohydrate, but dogs and cats do not have a dietary need for complex carbohydrates. For grains to be digested completely, they need to be cooked and chewed thoroughly. However, dogs do not chew their foods thoroughly. The reason pet food manufacturers use grains in dog and cat food is because they are a cheaper source of energy or calories, and they bind ingredients in the pet food together.

One vet, Russel Swift, DVM, believes that if grains are fed, dogs and cats cannot maintain the long-term production of amylase enzymes needed to digest grains. This combined with grains being less digestible cause the immune system to become weak and leads to food allergies and other chronic immune system problems. In addition to causing food allergies and immune system problems, feeding grains to your pet may contribute to obesity and diabetes.

In fact, most grains used in pet foods are not quality. They are grains left-over after processing grains for humans. Consequently, they have even less nutritional value.

Not only is the amount of protien important, but even more important is the biogical value or BV. Biological value is used to compare the usuability and digestibility of different protien ingredients. The calculation for this is: BV = (protien used/protien available) x 100. Eggs have the highest biological value of 100 followed by fish meal, milk, beef, soybean meal, and meat and bone meal. Although eggs are the standard other protiens are measured against for bioavailability, do not feed your dog raw eggs. Raw eggs contain avidin. Avidin interferes with the metabolism of fats, glucose, amino acids, and energy.

The biological value of a protien is a good indicator whether dogs will be able to extract the essential amino acids needed for a healty diet. Dogs need 22 amino acids. While dogs can synthesize 12 of these amino acids, the remaining amino acids cannot be synthesized. These amino acids are called essential amino acids. They include: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. A deficiency in any of these essential amino acids can cause health problems.

Although protein is important for dogs, fats are equally as important. They provide your dog with more than twice the energy of proteis and carbohydrates do. Fats perform many functions in the body. They provide structure for the cell walls, produce some hormones, absorb and utilizef fat-soluble vitamins, provide body insulation, protect internal organs, and provide a healthy coat and skin. Like amino acids, there are essential and nonessential fatty acids. The essential fatty acids for dogs and cats are linoleic acid and alpha linoleic acid. Furthermore, like humans, dogs need omega-3 and omega-6 fatty acids. Cats need arachidonic acid too. Arachidonic acid can be found in animal fats but not vegetable oils. They are important for reducing inflammation. The optimal ratio of omega-6 to omega-3 fatty acids is between 5 and 10 to 1.

Although there are no minimum requirements for carbohydrates, Donald Collins, DVM, suggests carbohydrates should make up 50% of a balanced, healthy diet for dogs. The fiber in carbohydrates modify the mix of bacterial populations in the small intestine. Some fibers are more fermentable than others. Highly fermentable fibers can produce more flatulence and mucous. Consequently, moderately fermentable fibers are the best. Examples of these are beet pulp and corn, rice, and wheat bran. Vitamins and minerals in the proper amount are also important.

Fat in dog food is prone to spoilage. If the fat spoils, it decreases the nutritional quality and make it less palatable. Consequently, dog food manufacturers use preservatives. Although natural preservatives like tocopherol and ascorbic acid are recognized as being safe, there are questions with the others. Even though the shelf life may be shorter with natural preservatives, it may be better fo your pet to avoid commercial pet foods with preservatives that are not natural. The following list are commonly used preservatives in dog food.

• BHT - This preservative is used to prevent fats and oils from going rancid. It is also used in cosmetics, jet fuels, pharmaceuticals, embalming fluid, petroleum products, rubber, and electrical transformer oils. In certain individuals, the liver may have problems breaking down this chemical, and it has even been banned as a food preservative in some countires.
• BHA (butylated hydroxyanisole) - According to the National Institute of Health, this chemical in the diet has been found to produce certain types of tumors in laboratory animals.
• Ethoxyquin - In addition to be used a preservative in dog food, it is also used as an insecticide and as hardening agent in making synthetic rubber. This preservative is allowed in dog foods up to 75 parts per million. Although it has been used in animal feed for over 30 years, lately consumers have been complaining about health problems in animals fed food with this preservative. A voluntary study done by Monsato in 1997 found it caused mild increases in certain liver enzymes and increases in a naturally-occuring red blood cell metabolite. In response to this, the FDA sent letters to dog food manufacturers using ehyxyquin as a preservative asking them to reduce the levels. Before this letter, it was allowed at 100 parts per million.
• Tocopherol (Vitamin E) - A natural preservative considered safe
• Ascorbic acid (Vitamin C) - A natural preservative considered safe
• Propylene Glycol - This is the chemical is used to retain the moisture content in commerical pet food, however, it is also anti-freeze. Since it is proven to cause blood toxicity in cats, it is banned from cat food, but it is still used in dog food. In some foods, it is high on the ingredient list in moist dog treats.

To understand what you're feeding your dog, it is helpful to know what exactly the ingredients contain.

• Meat/Meatbased - Clean animal flesh that includes organ meats, tendons, and blood vessles.
• Meat meal - Rendered meat that does not include hair, hooves, or stomach contents.
• Meat by-products - Clean organs, bones, blood, and fatty tissues.
• Poultry by-products - Clean chicken organs, feet, and heads.
• Poultry by-product meal - Rendered by-products with no feathers
• Meat and bone meal - Includes mean and bones. It does not include hooves, hair, blood, manure, hide, or stomach
• Tallow - Hard, white fat
• Animal digest - Chemically broken down animal tissue. It does not include horns, beaks, hooves, hair, feather, etc.
• Fish meal - Clean and dried fish

In response to the problems with commercial dog food, some pet owners have switched to BARF diets, Yes, I know; a BARF diet sounds unappealing. However, BARF stands for biologically appropriate raw food. According to Wikipedia, a BARF diets is composed of "...60% to 80% of raw, meaty bones (RMB), that is about 50% meat (eg. chicken neck, back and wings), and 20% to 40% of fruits and vegetables, offal, meat, eggs, or dairy foods."  While advocates think BARF diets are better because of the associated problems with commercial pet food, opponents think they are unbalanced. When one study compared the nutritional content of two commercial dog foods and three BARF diets, they found nutritional imbalances occurred in the BARF diets in multiple areas. Other criticisms of BARF diets are the use of whole bones can cause dental fracturers, intestinal obstructions, gastroenteritis, and intestinal perforations, Furthermore, raw meat may be unsafe for dogs and cats because of harmful bacteria and parasites. In response to these criticisms, BARF proponents claim that the intestinal tracts of dogs and cats can handle harmful organisms. If you are thinking about putting your dog on BARF diet, I would suggest you thoroughly research dog nutrition first and give them a daily vitamin/mineral supplement.

Now that you understand some of the problems with commercial dog food, you may decide to make your own dog food. However, if you still wish to buy commercial dog food, the following tips will help you buy a healthier dog food for your pet.

• Look for a lower percentage of carbohydrates.
• Avoid pet foods that have preservatives other than tocopherol and ascorbic C. If you're worried about shelf life and spoilage, buy smaller bags.
• Look for grains that are more digestible.
• Avoid meat and poultry byproducts.
• Avoid corn, wheat, and soybeans. They are more difficult for a dog to digest. Look for rice, barley, and oats instead.
• Dry dog food is usually more nutritious than canned dog food because it has less moisture content. Furthermore, dry dog food causes less tartar and plaque buildup on the teeth.
• For adult dogs, look for a dog food that has at least 20% to 30% protien content.
• Look for a dog food that has at least 2.5% to 4.5% fiber.
• While calcium and magnesium are essential minerals, omega-3 and omega-6 are essential fatty acids. Vitamins A, D, and E are essential too.

Like most consumers, it is easy to be fooled by the products pictures on the bag. We see a picture of juicy cut of meat and vegetable, and we automatically assume it is good for our dogs. Nothing could be further from the truth though. To know whether a commercial dog food is healthy we have to read the ingredient labels and understand what they mean. Next time you go to the store, take the time to check out the ingredients.