What Does "Complete And Balanced" On Pet Food Mean? - Part 3
What Does "Complete And Balanced" On Pet Food Mean? Part 3: What Is Complete And Balanced? The Micronutrients – Vitamins And Minerals
Looking now at vitamins and minerals (the micronutrients) most of these lack a maximum value in the AAFCO Complete and Balanced profile. However some do - for example vitamin D and Iodine. The fact that so many micronutrients lack a maximum unit of inclusion is concerning, with such worry justified as Bertrand’s rule lays out utilising a dose response curve for micronutrients. What this rule states is that initially, increasing benefits with increased intake occurs, however this is followed by increasing costs as excesses potentially become toxic7.
As a little scratching beneath the surface is performed, it is evident that the situation is more complicated that meets the eye. For example, zinc is a mineral with a minimum value of 80 mg/kg for adult maintenance, however this is significantly higher than the NRC. Why, is a fair and reasonable question to ask.
The answer is basically down to ingredients and absorption. Clearly, a lot of dogs are fed dog biscuits (or kibble), with a format of this type most usually high in cereals, grains etc. These products contain a compound called phytate (approximately 1.5%), which interferes with Zinc absorption8. Hence AAFCO decided feeding a higher level of Zinc to dogs was “good for all,” even though not all needed it (those fed diets with a low level of carbohydrates).
Another worthy point of mention, alluded to with regards to the Zinc example above is absorption. Setting a minimum, or even a maximum value for a nutrient must account for absorption. Unfortunately, although a reasonable statement to make, this is very difficult to achieve as both the supply of the nutrient (organic or inorganic) and other dietary ingredients all have a contributing role. A fitting example of this is that of phosphorus. Indeed, this mineral is in many ways usual in that, in addition to calcium, both have a minimal and maximal value for both adult maintenance and growth and reproduction (unlike most micronutrients), but also for large breed dogs. Additionally, it must meet a ratio range with that of calcium. All would hence appear to seem good on the phosphorus front, that is until we investigate bioavailability differences.
Although excessive phosphorus has also been recognised to carry with it health risk in both animals and humans, a recent study examined this is more detail, concluding:
“It is clear that excess phosphorus, especially when provided as highly soluble inorganic phosphate salts, can be damaging to kidneys9.”
In essence, the high level of bioavailability of these synthetic phosphates possess plays a vital role. Additionally, even if the levels of these inorganic sources are close to the maximum prescribed, or if a product mix is not adequately homogenized, the risk of renal issues developing is possible. A prudent approach would be one whereby the middle ground of the minimum and maximum range is adopted, with sourcing solely from inorganic, less bioavailable sources.
In summary, determining what nutrients and at what level they should be included in a diet for a dog is a complex issue, with many factors having a part to play. To highlight this, factors such as bioavailability, differences in ingredients and diet composition having been discussed. It would be logical to determine that using the National Research Council’s Publication for all dog nutrition is appropriate. However, the complexities of its guidance (for example not just having a minimum or maximum requirement, but also adequate intake, recommended allowance, and safe upper limit) make it impractical in the commercial setting. Consequently, a more general overview of a dog’s nutritional needs is what is followed. Of course, this may be viewed as worrisome, however, it must be understood that even if a so called “gold standard” of a nutritional profile was available, this would likely look significantly different in the not to distance future, as we learn more about the needs of our beloved pets.
- (2006). Nutrient requirements of dogs and cats: Washington, D.C: National Academies Press, c2006 (Rev. ed.).
- Pet Food Institute. (n.d.-a). History of Pet Food. Retrieved from http://www.petfoodinstitute.org/?page=HistoryofPetFood
- Association of American Feed Control Officials. (2019). 2022 Official Publication. Retrieved from Champaign, IL.
- Dzanis, D., A. (1994). The Association of American Feed Control Officials Dog and Cat Food Nutrient Profiles: substantiation of nutritional adequacy of complete and balanced pet foods in the United States. The Journal of nutrition, 124(12 Suppl), 2535S-2539S.
- Zicker, S. C. (2008). Evaluating pet foods: how confident are you when you recommend a commercial pet food? Topics in Companion Animal Medicine, 23(3), 121-126.
- The European Pet Food Industry Federation. (2018). Nutritional guidelines for complete and complementary pet food for cats and dogs. Retrieved from http://www.google.co.nz/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjIjfGC8-nJAhWILmMKHUgkC30QFgghMAE&url=http%3A%2F%2Fwww.fediaf.org%2Ffileadmin%2Fuser_upload%2FReports%2FNutritional___Analytical_Science%2FNutritional_guidelines.pdf&usg=AFQjCNGXTrsdl2awyhI2pc1yiIH47P9emw
- Raubenheimer, D., Lee, K. P., & Simpson, S. J. (2005). Does Bertrand's rule apply to macronutrients? Proceedings of the Royal Society B: Biological Sciences, 272(1579), 2429-2434.
- Erdman, J. W. (1979). Oilseed phytates: nutritional implications. Journal of the American Oil Chemists’ Society, 56(8), 736-741.
- Laflamme, D., Backus, R., Brown, S., Butterwick, R., Czarnecki‐Maulden, G., Elliott, J., ... & Polzin, D. (2020). A review of phosphorus homeostasis and the impact of different types and amounts of dietary phosphate on metabolism and renal health in cats. Journal of veterinary internal medicine, 34(6), 2187-2196.