In all the debates here and elsewhere about the relative merits of commercial pet diets and homemade, raw, or other alternatives, advocates of alternative diets often claim that conventional diets are unhealthy. Scientific evidence is not typically provided to support these claims, of course. Similarly, alternative dietary approaches are often claimed to be healthier than conventional diets, but there is no scientific evidence to support this belief. What this means is that, while there may be health risks associated with commercial diets and health benefits associated with alternatives, we don’t know what these are, which animals are affected, or how important the effects may be. Without real evidence, not simply anecdotes, claims about nutrition for our pets are simply opinions.
There is, however, some scientific evidence relevant to these issues. I’ve reviewed some research, for example, looking at claims regarding raw foods. This research so far fails to show any health benefits but does support the potential for risks associated with infectious organisms in raw meat. I have also reported on some of the research showing that homemade diets are often nutritionally imbalanced or incomplete, which would likely negate any potential benefits to the fresh ingredients used to make them.
A recent review paper adds a bit of perspective to this subject by reminding us that there is also research evidence illustrating the beneficial effects of some scientifically formulated diets that veterinarians use for specific health problems.
Davies M. Veterinary clinical nutrition: success stories: an overview. Proc Nutr Soc. 2016 Aug;75(3):392-7. doi: 10.1017/S002966511600029X. Epub 2016 Jun 8.
This brief article discusses the evidence for some of the clearest examples of therapeutic diets that have real benefits for patients. These include:
- Diets formulated for dogs and cats with kidney disease, which improve quality and length of life as well as laboratory markers of disease.
- Diets for dissolving certain urinary tract stones, which allow cats and dogs with these stones to avoid surgery
- The discovery of the link between taurine deficient diets and cardiomyopathy, a life-threatening heart condition in cats that has been nearly eliminated by dietary supplementation of taurine.
There is also discussion of some less clear examples, including the potential use of dietary therapy for hyperthyroidism in cats and the use of special diets for treatment of arthritis and support of dogs undergoing chemotherapy treatment for lymphoma. These diets appear to have some benefits in these cases, though the evidence is not quite as robust.
Obviously, these examples don’t answer the larger questions about the relative risks and benefits of different dietary approaches. But they do illustrate that using scientific methods, we can develop diets that have measurable and significant health benefits. This is far more promising than simply relying on unsupported nutritional theories, haphazard trial and error, or anecdotes, which is the kind of evidence usually used to justify alternative nutritional practices.
As usual, I expect the comments will include the following invalid arguments, so I will address them pre-emptively:
- Vets know nothing about nutrition. Actually, they do know something.
- But I fed my dog X and then Y happened. Why We’re Often Wrong Testimonials Lie The Role of Anecdotes in Science-Based Medicine Why We Need Science: “I saw it with my own eyes” Is Not Enough Don’t Believe your Eyes (or Your Brain)