Nutraceuticals: principles and uses

Introduction

• The term "nutraceuticals" is used for compounds given orally that are legally considered neither food nor drug. It includes essential nutrients in supraphysiogical doses such as selenium and vitamin E, extracted food compounds taken for medical purposes such as fish oils, phytochemicals and conditionally essential nutrients, enzymes and probiotics.Herbs/botanicals such as gingko biloba can be classed as their own class of dietary supplement rather than a nutraceutical. They are generally more complex and variable than most nutraceuticals with a very different history of use.
• The North American Veterinary Council has defined a nutraceutical as: " a [non-drug] substance which is produced in a urified or extracted form and administered orally to a patient to provide agents required for normal body structure and function and administered with the intent of improving the health and wellbeing of animals".
• These novel products are very popular; it has been estimated that nearly 30% of pet owners have used or considered the use of novel ingredients for their pets. Because herbs and other novel ingredients are often perceived as natural many people also feel that they are safe and that they are a milder intervention than drugs; however, amanita mushrooms are also natural, and highly deadly .
• The combination of Ma Huang and guarana is used in some weight loss supplements for dogs. Ma Huang contains ephedrine and guarana contains caffeine. These compounds affect the central nervous system and cardiovascular system, and in one study caused the death of 17 of the dogs given this type of product. Further, many of our current drugs are originally derived from plants, eg digoxin (originally from the foxglove plant), so the potential effects and toxicity of these products should not be underestimated.
• To become licensed, drugs must undergo rigorous safety and efficacy testing; nutraceuticals do not have the same requirements. Labeling of licensed medications is highly regulated to ensure that the labeling reflects the contents of the package; nutraceuticals do not have the same regulations. A study has shown mislabeling in 84% of nutraceutical products studied; with the amount of mislabeling ranging from 0% to 115% of the actual product in the package.
• Determining appropriate dosing for medications involves knowledge of the pharmacokinetics, or how the drug is absorbed, distributed within, and excreted from the body. With compounds such as herbs, there may be hundreds of active ingredients, making this process challenging. Determination of efficacy of the products requires measurable outcomes; a few studies in nutraceuticals have been done to try to measure these, and more scientific evidence is becoming available about some of the products. However, most nutraceutical dosages are empirical as there is insufficient data on the efficacious dose.
• The absorption, metabolism and excretion of products differ among species, so that extrapolation from one to another may be incorrect or unsafe. For example, lipoic acid has been used as an antioxidant in dogs, but is dangerous to use in cats.
• Antioxidants, herbs, and chondroprotectants are among the nutraceuticals used in veterinary medicine. The chondroprotectants, such as glucosamine and chondroitin sulphate are the precursors of cartilage and are sometimes used orally to support cartilage synthesis in pets with osteoarthritis . The use of nutraceuticals as chondroprotectants has been addressed elsewhere and will not be discussed further in this component.

Sources

Publications

Refereed papers

• Recent references from PubMed.
• Araujo J A, Landsberg G M, Milgram N W, Miolo A (2008) Improvement of short-term memory performance in aged beagles by a nutraceutical supplement containing phosphatidylserine, Ginkgo biloba, vitamin E, and pyridoxine. Can Vet J 49( 4), 379-85 PubMed.
• Osella M, Re G, Odore R, Girardi C, Badino P, Barbero R, Bergamasco L (2007) Canine cognitive dysfunction syndrome: Prevalence, clinical signs and treatment with a neuroprotective nutraceutical. Appl Anim Behav Sci 105 (4), 297-310.
• Cupp C J, Clementine J P, Kerr W W, Patil A R, Perez-Camargo G (2006) Effect of nutritional interventions on longevity of senior cat. Inter J Appl Res Vet Med 4 (1),1-18.
• Roudebush P, Zicker S C, Cotman C W, Milgram N W, Muggenburg B A, Head E (2005) Nutritional management of brain aging in dogs. J Am Vet Med Assoc 227 (5), 722-728 PubMed.
• Center S A (2004) Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of heptobiliary disorders. Vet Clin North Am Small Anim Pract 34 (1) 67-172 PubMed.
• Hayek G, Massimino S P, Ceddia M A (2004) Modulation of immune response through nutraceutical interventions: implications for canine and feline health. Vet Clin North Am Small Anim Pract 34 (1), 229-247.
• Boothe D M (1997) Nutraceuticals in Veterinary Medicine. Part 1. Definitions and Regulations. Compend Contin Educ PracVet 19 (11),1248-1255.

Other sources of information

• Harper J (1999) Dietary antioxidants in cat and dog nutrition. Waltham Focus 9 (2), 32.