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Wednesday, January 14, 2015

Nutrition Week, #2: Raw Foods, Bones, Meat

Continuing our discussion on pet nutrition....
Myth #4:  Raw food diets are better than commercially prepared diets
Raw foods carry a significant risk for bacterial contamination.  Studies have sown that 20%-35% of raw poultry and 80% of raw food diets for dogs tested positive for Salmonella, while 30% of stool samples from dogs fed these diets were positive for Salmonella.  While a healthy dog may be able to cope with some dietary bacteria, others cannot.  There is also a significant human health risk of exposure to dangerous bacteria.  Numerous parasites can be found in raw food, presenting a risk to the health of the pet and their human families.  Raw diets have been consistently shown to contain imbalances in the Calcium:Phosphorous ratio, excessive Vitamin A and D, and other mineral imbalances.  There have been no controlled, scientific studies that have shown raw diets to be better for the health of pets than commercially prepared foods.  As with grain-free diets, any perceived benefits are likely due to a higher fat content and lower fiber content rather than the issue of raw versus processed foods.
(also see previous discussions here and here)
Myth #5:  Bones are good for dogs and cats
Studies of wild dogs and cats have shown no differences in the rate of dental disease compared to pets, even though wild carnivores chew on bones frequently.  Bones are very hard and are a frequent cause of fractured teeth, which can be very painful and require dental extractions.  Small or splintered bones cause a risk of obstructing or puncturing the esophagus, stomach, or intestines.
Myth #6:  Meat should be the first ingredient
The ingredients are listed on pet food bags by pre-cooked weight.  So the first ingredient weighs more than the second before they are processed, and so on.  Meats contain a high level of water, which is removed during cooking and processing.  Water is heavy, so the pre-cooked weight is not a good indication of the percentage of nutritents that actually come from that food.  "Chicken meal" as the third ingredient, may actually contain more protein than "Chicken" as the first ingredient because the meal has been ground and dehydrated, removing the water.  So ingredients on the list are placed lower merely because they weigh less, not because they carry fewer nutritents or contribute less to the diet.  If "chicken", "poultry meal", and "corn gluten meal" are all included on an ingredient list, there is no way to tell from the packaging which ingredient actually contributes more protein than another, since the ingredients are listed by weight and not by nutrient density.  A perception of the seeming benefit of "meat" may be the fact that this ingredient contains more fat that "meal", which as discussed above can result in a glossier coat but doesn't mean the nutrition is better.
(also see previous discussion here)