A little over a year ago, I reported on the formation of a National Research Council (NRC) committee charged with looking at the safety of dietary supplements for non-food-producing animals. While the committee's members were not finalized at that time, I was honored to subsequently be confirmed as a participant in this expert panel.
Now I'm pleased to say the preliminary report of this committee has been released to the public - Safety of Dietary Supplements for Horses, Dogs and Cats . On the same webpage, you may also preorder the final version, which should be available soon. While there shouldn't be too many changes between the two versions, I'd recommend purchasing the final.
The task from FDA
Many of the ingredients permitted in dietary supplements for human consumption under the Dietary Supplement Health and Education Act (DSHEA) are problematic when incorporated in animal feed or petfood products. Also, the available data to support safe use of these substances in products intended for animal consumption are usually insufficient to meet current regulatory criteria. Notwithstanding enforcement efforts at both the federal and state levels, animal products containing unapproved and potentially unsafe food additives are available in the marketplace.
The task of the committee, therefore, was to provide the US Food and Drug Administration (FDA) with insight on how to evaluate the safety of these types of ingredients, focusing on those intended for consumption by the major non-food-producing species (horses, dogs, and cats). The FDA's Center for Veterinary Medicine funded the work of this committee.
The eight committee members were diverse in background and expertise, including animal and veterinary nutritionists, a veterinary toxicologist and a veterinary pharmacologist. While the majority of the members were academicians, two were employees of petfood manufacturers and one a consultant to the petfood industry.
What the report says
As a first step in describing the issue, the report provides a working definition for "animal dietary supplement":
A substance for oral consumption by horses, dogs or cats, whether in/on feed or offered separately, intended for specific benefit to the animal by means other than provision of nutrients recognized as essential, or provision of essential nutrients for intended effect on the animal beyond normal nutritional needs, but not including legally defined drugs.
This is distinctly different from the definition for "(human) dietary supplement" in DSHEA. The latter definition applies only to items offered in supplement (i.e., dosage) form versus conventional food form and applies to essential nutrients as well as non-essential substances. For the NRC report, it was critical to include substances regardless of feeding method (incorporated into the diet or fed separately) and to purposefully exclude recognized dietary essential nutrients for which the existing regulatory oversight is generally sufficient to ensure safety.
Besides the definition, the report discusses the current regulation of animal dietary supplements and how it compares to regulation of human supplements under DSHEA. Subsequent chapters discuss:
Methods available to assess animal dietary supplement safety (both pre- and post-marketing);
Factors affecting animal dietary supplement safety (e.g., source, processing, physiology, species differences); and
Categories of scientific evidence for assessing the strength of available data on animal dietary supplement safety.
Together, these chapters offer a strong basis by which the safety of an animal dietary supplement may be evaluated.
Using these findings, the report looks at three specific animal dietary supplements in depth: lutein, evening primrose oil and garlic. The committee reviewed the available data, assessed safety and, where it could, offered presumed safe intake levels for each of these substances for each of the three species. The report concludes with a discussion of general considerations for determining safety as learned during the study of these three examples. There is also a four-page summary available .
Impact of the report
The report is not intended to offer FDA a regulatory framework or advise it on how to regulate animal dietary supplements. However, it is intended to help the agency develop a means to evaluate the safety of the many animal feed and petfood ingredients that are often lacking in the quantity or quality of data to support their use through current regulatory methods. What procedures FDA will implement as a result of this report is not yet known, but I trust the agency will find the report useful.
I hope petfood and pet supplement manufacturers will also find the report helpful in their efforts to ensure safety of marketed products. While companies cannot rely on the report to the same degree as a regulatory authority, it offers sound guidance to the type and strength of data that may be needed to support safe use.