By Dr. Bec Crawford, DVM CertAqV BSc (Hons)

To follow our conversations around wild-type pet foods, shark cartilage and endangered species found in pet products comes this introduction to pet food and supplements. 

Food, generally recognized as safe (GRAS) by the FDA, requires a consensus among experts regarding product safety. Feed additives are not GRAS; these products are considered unsafe unless a regulation specifically exists providing for its safe use following a premarket approval process. Dietary supplements (nutraceuticals) are minimally regulated for humans and pets, and with that being said, safety and efficacy guarantees allow for bias on part of the manufacturer. Label claims on supplements for human consumption attach some form of the following disclaimer: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.” More strictly, each ingredient utilized in an FDA-approved drug (pharmaceutical) must be individually evaluated for assurance, efficacy, and safety. 

Let’s dive deeper into the history behind food, nutraceutical, and pharmaceutical regulation. Following the formation of the Food and Drug Administration (FDA) in the early 1900s, the Federal Food, Drug and Cosmetic Act (FFDCA) of 1938 intended to ensure the safety of defined foods, drugs, and feed additives entering the human food chain. In 1962, an amendment assured drug efficacy in the mission of the FDA, and in 1968, the Animal Drug Amendments provided for the formation of the Center for Veterinary Medicine (CVM) intending safe drug use in agricultural animals for human consumption to protect humans from drug residues in meat and milk. The Dietary Supplement Health and Education Act (DSHEA) of 1994 amended the FFDCA to effectively restrict the ability of the FDA to regulate dietary supplements, legally defining a dietary supplement as applying only to human products. In 2007, the FDA Amendments Act (FDAAA) included a section requiring the FDA to set ingredient definitions and processing standards for pet foods, modifying pet food labels, and creating a food adulteration incident reporting system. In 2008, AAFCO and the FDA signed a memorandum of understanding (MUO) where the FDA assumed greater authority over the feed ingredient definition process, and AAFCO developed regulations to institute good manufacturing practices (GMPs) for all animal feeds.

In 2022, the American Association of Feed Control Officials (AAFCO) remains a nonregulatory organization governed by federal and state feed officials with voluntary guidelines adopted on a state by state, voluntary basis. Approved products sold within participating states must contain defined and recognized ingredients per AAFCO. Enforcement Strategy for Marketing Ingredients (ESMI) is an AAFCO regulatory program designed to address ingredients with unapproved claims as is common with the nutraceutical industry. The National Animal Supplement Council (NASC) of the United States, the Nutraceutical Alliance of Canada, and the North American Veterinary Nutraceutical Council (NAVNC, now nonexistent) have attempted to develop adverse reaction reporting systems, establish quality controls, and fund further research and support for quality pet supplements. All this to say, the regulation of nutraceuticals, pet supplements in particular, is essentially nonexistent. 

Nutraceutical, a nonlegal term since 1989, has been used to describe botanicals, designed and genetically engineered foods, dietary supplements, functional foods, herbal and nonherbal phytochemicals, hyper nutritious foods, pharmafoods, processed human foods, and selected nutrients. These various supplemental oral compounds, classified as neither nutrients nor pharmaceuticals, are marketed for use to improve the health of people and pets. Nutraceuticals do not undergo a premarket approval process, and neither safety, manufacture process nor efficacy is assured before a product hits the shelves. Nutraceuticals are only investigated by the FDA when a product is discovered to be associated with a label that claims drug use or is discovered to be unsafe.

Now I know you’re backtracking and reading that again, and the answer is yes, nutraceuticals are sold in the absence of clinical trials to ensure efficacy and safety for people and pets. When it comes to assessing the validity of scientific information supporting safety and efficacy claims, it is a common opinion that clinical trials for pharmaceuticals should likewise apply for nutraceuticals, but this is not enforced. Quality assurance verification is possible through Consumer Laboratory; a for-profit, independent, third-party that offers a seal of validation for dietary supplements sold in the United States. 

JOINT SUPPLEMENTS FOR PETS

With a primary focus on joint health given that osteoarthritis is one of the most common ailments in pets, the most commonly marketed nutraceutical ingredients for pets are chondroitin sulfate (CDS), collagen, glucosamine (GS), hyaluronic acid (HA), methylsulfonylmethane (MSM), squalene and its hydrogenated form, squalane. Glycosaminoglycans (GAGs) include nonsulfated types such as hyaluronic acid and sulfated types such as chondroitin sulfate, together with glucosamine utilized in joint supplements to supply the building blocks of cartilage with the mind to maintain healthy lubricated joints. Chondroitin is often derived from chicken, cow, pig or shark cartilage; collagen from chicken and other poultries; glucosamine from bone, cartilage, corn, crustaceans such as crab and shrimp, and shellfish such as New Zealand green-lipped mussel; hyaluronic acid from bone and vegetables; and squalane and squalene from either plants or shark liver. 

Chondrocytes (cartilage cells) in joints are not capable of regenerating; as is the case for humans, the replacement of cartilage for pets must be performed via transplantation into the joint with stem cell therapy. This is usually cost-prohibitive, so parenteral or oral administration of the building blocks of joints is typically pursued for pets. Absorption or biological availability of chondroitin and glucosamine varies by product and species; both CDS and GS have been shown to be increasingly absorbed through the gastrointestinal tract of dogs with consistent administration. Both are virtually unabsorbable when supplementation begins and then increases over time. Beneficial levels incorporated into foods and supplements, molecular form and size, as well as stability of CDS and GS are unknown, but both do show higher concentrations in joints than in blood following prolonged oral administration. New Zealand green-lipped mussel is a source of omega 3 polyunsaturated fatty acids (N3 PUFAs) rich in glycosaminoglycans (GAGs), however, no studies exist to substantiate the evidence of absorption of GAGs from this product in cats or dogs. Given that N3 PUFAs destabilize via oxidation rapidly, it is important that products containing these molecules incorporate a stable form to ensure the proposed benefits, but no regulatory system exists to monitor this. 

Deviations from pet nutraceutical label claims have been found on average in 9 of 11 products (84%) with deficient products containing <10% of the claimed amount and partial mislabelling of products in 100% of those reviewed. (Adebowale AO, et al. Analysis of glucosamine and chondroitin sulfate content in marketed products and the Caco-2 permeability of chondroitin sulfate raw materials. Journal of the American Nutraceutical Association 2000;37-44). 

As an alternative to over-the-counter supplements, especially if your pet has been diagnosed with an orthopedic condition such as osteoarthritis or degenerative joint disease, please consult your veterinarian about FDA-approved alternatives; prescription products are safer for your pet, proven to work, and more cost-effective in the long run. 

Actionable Items

• Avoid squalane and squalene derived from shark liver. Since most products will not list their source, we encourage you to reach out to your manufacturer to inquire as to whether the squalane/squalene in your product is plant or shark-sourced.

• Do your own research and read more about over-the-counter joint supplements for your pet via Consumer Laboratory. 

• Seek recommendations from your family veterinarian in managing your pet’s osteoarthritis.

Watch this space for more to come on pet food labeling and regulation.