Nutrition 101

Commercial pet food first hit the market in the 1920s, with many of the more famous brands launching in the 1940s and 1950s. Today, with the selection ever expanding, many people feel overwhelmed and confused by the array of pet foods available.

By working in partnership with your veterinarian throughout your pet's life, however, you can best ensure the right nutrition for your pet's changing needs. As background for those conversations, here's an introduction to the basic nutritional requirements of dogs and cats.

WHAT DOGS NEED

Just like with human food intake, dogs require a balance of fats, proteins, and carbohydrates.

• The body needs fats for certain biochemical processes, especially in the brain and nervous system. In addition, a bit of stored fat allows the body to properly process fat-soluble vitamins.
• Protein provides nutrients and energy. It also supports muscle development and maintenance.
• Carbohydrates provide both nutrients and energy.

Most high-end dog food brands also include omega-3 and omega-6 fatty acids to promote good health, including a lush coat and healthy skin.

According to Rebecca Ruch-Gallie, DVM, MS, an associate professor in community practice at Colorado State University's Veterinary Teaching Hospital, "Good-quality foods provide the nutrients, vitamins, and minerals that are needed to keep pets healthy. A vitamin supplement is not necessary if you're feeding a good-quality diet."

The levels and balance of the ingredients and nutrients that dogs need change as they mature. Puppies, for example, need more calories than adult dogs to help them grow. Adult dog foods, however, don't just have fewer calories; other nutrient shifts are also needed. As they move into their senior years, dogs may need a diet that contains yet another mix of fats, proteins, and carbohydrates. Senior dogs also generally need higher levels of fiber and fewer calories, although some aging dogs may actually need more calories. For dogs with specific health problems, therapeutic diets formulated to meet their needs are available.

It's important to match the food not only to your dog's life stage but also to his lifestyle. For instance, performance dogs, who are typically very athletic, have different needs than strictly backyard pooches. Because performance food is packed with extra protein and calories, feeding it to a traditional family dog is like putting rocket fuel into the family car.

Ask your veterinarian what food he or she recommends to keep your dog healthy.

BIG DOGS, LITTLE DOGS, AND AGING

Large-breed pups need to be fed differently than smaller pups, so if your puppy is a large breed, work with your veterinarian to ensure that he is getting the right balance of nutrients. "Large breeds need to be able to grow at a steady state as their growth plates are open so there aren't any changes in the angles of the joints," Dr. Ruch-Gallie says. "If those angles don't end up being the right ones as they get older, you can have serious orthopedic problems."

The differences in breed size affect how puppies grow. For instance, whereas a bulldog can reach 40 pounds after 20 weeks, a Saint Bernard puppy can reach 100 pounds in 20 weeks (passing 40 pounds at only 8 weeks). What's interesting, however, is that not all dogs are considered adults or seniors at the same age. Although large-breed puppies physically grow faster than smaller-breed puppies, smaller breeds actually reach adulthood faster than their larger counterparts. Once they reach adulthood, dogs age differently depending on their size. Big dogs age much faster than smaller-breed dogs, which is why smaller breeds tend to live so much longer.

DIET ISSUES

Pet owners often think of food choice as simply finding something the dog will eat that he's not allergic to, but not all food issues are strictly related to allergies. A low-grade intolerance to a food, even if it's intermittent or crops up after years of doing well, might indicate that a change in diet is needed. Consult your veterinarian to find and treat any medical issues and to discuss food options if you notice any of these symptoms in your dog:

• Chronic ear or skin infections
• Inability to lose weight, despite strict portion control
• Inability to thrive or sudden weight loss
• Intermittent vomiting or diarrhea 
• Picky eating (sometimes there's a reason they're being picky)
• Poor appearance of skin and coat
• Tartar buildup on teeth, despite regular brushing and professional cleaning

NUTRITIONAL TEAMWORK

When discussing your dog's diet and nutrition with your veterinarian, Dr. Ruch-Gallie recommends being entirely honest about your concerns and preconceptions. "Veterinarians would rather you ask them the question so they can address whatever issues or concerns you have or rumors you've heard," she says. "Ask, rather than just thinking in the back of your mind, 'I have concerns about that, but I don't want to second guess them.' We're used to being second guessed. We prefer to be asked and given the chance to assure owners."

Feeding too many treats can unbalance a diet. If your pet is on a therapeutic diet, ask your veterinarian what kinds of treats are appropriate.

Deciding Which Food Is Right for Your Pet

In the wake of the 2007 pet food recalls, there's an ongoing and lively debate about what to look for in a pet food. Here are two musts:

Make sure the food is complete and balanced for a single life stage (puppy/kitten, adult, or senior). "Remember when all the high-tech stuff came out, and you had a printer that also is a scanner and a fax machine all in one? It didn't do any one thing really well," says Dr. Ruch-Gallie. "It's kind of like that with nutrition. You want something for your pet's life stage, not all life stages."

Choose a food made by a reputable company. With so many brands from which to choose, it's best to stick with a company that has a solid reputation for producing quality products.

Pet food labels can seem like they're written in a foreign language. To get help deciphering yours, cut it out and bring it when you meet with your veterinarian so that you can better match foods to your pet's individual needs. Your veterinarian can also recommend a high quality food for your pet.

 The Cat Food Difference

Cats have different nutritional needs than dogs. "Cats are obligate carnivores, which means they require meat as part of their diet. They are not omnivores like dogs," explains Karyl Hurley, DVM, DACVIM, DECVIM, an adjunct faculty member at Cornell University who used to work for a pet food company.

Cats require specific amino acids found in meat food sources (such as taurine and L-arginine) because they cannot synthesize them from other sources. Without these nutrients, Dr. Hurley adds, cats can develop serious health problems. Your feline family members also require preformed vitamins A and D, which should already be in the food if it is a balanced diet.

Like dogs, cats need a higher calorie intake while they're growing and less as neutered adults. (Most cats typically reach adulthood at 8 to 12 months of age.) Also like dogs, cats' nutritional needs change when they become seniors. However, although some large-breed dogs are considered to be seniors as early as 5 years of age, cats reach senior status when they're older, between 7 and 12 years of age (because they generally live much longer than dogs).

Whereas dogs gain weight and tend to keep it on, many cats begin life as trim, active kittens and young adults before getting overweight in their middle years, then becoming thin seniors." Cats do get thin again," Dr. Hurley says." Part of the reason is that they have a harder time digesting food as they get older."

Cats also differ from dogs in their level of water consumption. You typically do not see cats lapping water from a bowl. That's why wet food can be important, especially as cats age and face urinary or kidney issues." By age 15, a large percentage of cats have kidney disease, so wet food is a really good way of getting them to take in more water," explains Dr. Hurley.

The decision to feed dry food, wet food, or a combination of the two really depends on your lifestyle, your budget, and your cat. Because cats nibble up to 14 times a day, rather than eat "meals," leaving dry food out is convenient. Keep in mind, however, that dry food typically features a higher calorie content than wet food, with a difference as high as 400 calories between brands. So if your cat does have weight issues, measure and monitor his dry food intake carefully.