Variety Is Important for Nutritional Completeness
Renowned nutritionist deplores reliance on single-recipe diets
News item written by Mary Straus, published in the Whole Dog Journal, November 2009
Marion Nestle is the award-winning author of Pet Food Politics: The Chihuahua in the Coal Mine, the story of the massive pet food recall in 2007, and the upcoming Feed Your Pet Right: The Authoritative Guide to Feeding Your Dog and Cat, due out in May 2010. A renowned professor of nutrition, food studies and public health, Nestle’s interest in nutrition extends to both people and pets.
In her Pet Food Politics blog, Nestle recently wrote about the limitations of nutrition analyses and databases as aids for creating healthy diets for people. I was surprised by how closely her words echoed my own feelings in relation to the drawbacks of relying on a single recipe developed with a spreadsheet to feed a dog.
Referring to the databases used to create these recipes, Nestle says, “If you give it even a moment’s thought, you realize that the nutrient contents have to vary with growing location, soil conditions, climate, transportation, and storage, so the amounts given in the database can only be approximations of what you are actually eating[our emphasis]. The data aren’t meaningless, but they don’t mean nearly as much as people think they do.”
Exactly. Too many recipes created with spreadsheets, including those from veterinary nutritionists, provide only minimal amounts of important nutrients. If the foods used to create these recipes don’t match up to the numbers in the database, the recipes are likely to be lacking in some areas. Feeding the same recipe and nothing else for long periods of time may lead to nutritional deficiencies.
The same problem can occur when you feed one commercial food exclusively. Even foods that state they are formulated to contain "complete and balanced" nutrition for dogs may not actually do so for a number of reasons. These include how the food is stored; changes in the ingredient sources; and whether laboratory analysis of the food itself was conducted to confirm its nutrient content (as opposed to tests of a similar food from its maker, or a feeding trial to determine its nutritional adequacy).
I recommend choosing at least two or three different brands, using different protein sources, and rotating among them anywhere from daily to every few months. If one food is deficient in some areas, the odds are that the next food will make up for it, especially if it’s made by a different company -- though that food may be deficient in other areas.
Spreadsheets have their place, especially when you need to control specific nutrients due to health problems. A spreadsheet can help you determine how to limit phosphorus in diets for dogs with kidney disease, for example. Even then, it's safer to use multiple recipes that include different ingredients rather than always feeding the same recipe. A spreadsheet should also be used if you’re feeding a single recipe for any reason, to identify any obvious nutritional imbalances.
Nestle goes on to say, “We know from studies using experimental animals that it is extremely difficult to induce nutrient deficiencies in animals that are fed a variety of foods providing sufficient calories. The best way to avoid nutrient deficiencies is to eat a variety of minimally processed foods. If you do that, you don’t have to worry about specific nutrients.”
Food for thought indeed. Rather than relying on a single recipe created with a spreadsheet to ensure that your dog’s nutritional needs are being met, feed a wide variety of fresh foods in appropriate proportions; that's the best way to create a healthy diet for your dog, as well as for your family.
If you have any questions or comments, please contact me. My name is Mary Straus and you can email me at either or