By Dr. Becker
There's a reason most pet food companies cook the life out of the products they sell.
Extreme processing provides a number of benefits to manufacturers, including convenience, consistency from one product batch to the next, pathogen containment, decreased spoilage, and the opportunity to artificially enhance flavor and texture.
Of course, excessive processing also destroys essential nutrients in the ingredients and creates noxious by-products.
According to PetfoodIndustry.com:
"Petfood is unique.
Unlike with human foods, many of the starting ingredients used in commercial petfoods have already been extensively processed (e.g., meat and bone meal, tallow, rice bran, etc.), all of the ingredients in the diet are mixed together and then processed under fairly harsh conditions (e.g., extrusion) and the finished product is expected to be shelf-stable for more than a year under ambient conditions.
Human foods are typically singular ingredients or dietary components, only a portion of which are processed, they are eaten a la carte in multiple meals throughout the day and most are refrigerated, frozen or consumed within weeks of production.
Livestock feeds use a similar all-in ration approach like petfoods, but the final diet is seldom heat-processed and is commonly fed the same day it's produced, so shelf life is of little concern.
These differences have profound implications on the nutritional value of the final product."
Let's take a closer look at how extreme processing of pet foods depletes their nutritional value.
Pet food manufacturers consider the biggest challenge to be the effects of the rendering process on the nutritional value of raw ingredients.
I would argue that not only is the rendering process itself a problem, but so are most of the questionable raw ingredients used in the process – a process which creates 'protein meals' like meat and bone meal or chicken by-product meal from food deemed unfit for human consumption.
Since many rendered ingredients in pet food are a highly variable mixture of somewhat-digestible and indigestible protein sources, they don't necessarily even start out nutritious. After the rendering process and further extensive cooking, additional nutritional degradation is the result.
The nutrients in proteins most at risk during processing are essential amino acids (for example, lysine), the sulfur amino acids methionine and cysteine, and essential fatty acids. These happen to be nutrients absolutely vital for your pet.
Dogs and cats need 22 amino acids to be healthy. Dogs can make 12 of the 22; cats can make 11. The remaining amino acids must come from the food they eat, which is why they're called 'essential' amino acids.
Essential fatty acids are functional fats. They are vital to your pet's health, but she can't make them on her own. They must come from her diet.
Essential fatty acids are the omega-6 and omega-3 fats. They play a huge role in your pet's health, especially the omega-3s.
Carbs in the form of starch really have no place in a species-appropriate diet for carnivores. Starch provides calories, but little if any nutrition, and the GI tracts of dogs and cats aren't equipped to process large quantities of carbs.
Despite all that, starches and grains are certainly an often-used ingredient in many commercially available pet foods, and are actually essential in forming the little kibble shapes in dry food.
Cooking and processing of starchy ingredients can actually improve their digestibility. However, excessive cooking can turn them into 'resistant starch,' which is even more difficult for your pet to digest than less processed starch.
So not only are these ingredients inappropriate nutrition for carnivores, they're often processed to such an extent they present a real digestibility challenge for cats and dogs.
Virtually all vitamins in the raw ingredients used in pet food formulas are affected by processing. At each step in the process -- from premix to production to packaging and storage -- the availability of essential vitamins steadily declines.
The fat-soluble vitamins A, D, E and K in raw ingredients lose over half their nutritional value before extruded dry pet food even reaches the packaging stage of the process.
In wet pet food, the water-soluble B-vitamin thiamine is often almost completely depleted as a result of processing.
Fortified by Nature is Better Than "Refortified" By Pet Food Manufacturers
The challenge for pet food manufacturers is to 'refortify' their formulas with nutrients lost to processing – adding back in enough, but not too much.
According to PetfoodIndustry.com:
"Today, we support nutritional adequacy by super-fortification before and nutrient analysis after the fact. Generally, this has proven effective, but occasional toxicities and deficiencies resulting in recalls occur. This would suggest that we still need more comprehensive evaluation of the nutritional effects of thermal processing of petfoods with better models to support fortification needs."
Real food in its whole, unprocessed form doesn't need to be fortified. For the sake primarily of convenience and to some extent affordability, real whole food is processed until much of its nutritional value is destroyed.
The challenge for you as a pet owner is to determine whether you're feeding your dog or cat a commercially processed pet food that may or may not provide consistently adequate -- and preferably optimal -- nutrition. Learning to read pet food labels is a great first step in the decision-making process.
In terms of quality, commercial pet foods run the gamut from very poor to excellent – but you first need to know what to look for.
Another option is to prepare your pet's food yourself, using whole, raw, unprocessed foods. Foods that have not been processed or dehydrated are the best nutrition for your pet's body. It's important you follow a recipe to assure nutritional adequacy and balance if you make a homemade diet.
These foods are biologically appropriate. All the moisture in the food remains in the food. Foods that have been extruded and otherwise processed can have drastically depleted moisture content. It can drop from 70 percent down to as low as 12 percent. Your pet's kidneys and liver can become stressed due to chronic low-grade dehydration.
Pet food in its natural state provides the highest level of nutrition for your dog or cat.