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Pet supplements - are they necessary?

Pet supplements - are they necessary?

The world of pet supplements is diverse, with a wide range of products offering all sorts of functions and benefits. But what should pet professionals advise pet owners when asked about supplements?



Published on 15 May 2020

By Sarah Hormozi, PFMA Head of Science and Education



What are pet supplements?

While there is no legal definition for pet ‘supplement’ in the EU law, the term generally refers to complementary pet food products offering additional nutrients or functional ingredients, as well as a vast range of snacks and treats. It is therefore important to understand the function and benefit of each of these products before recommending them to pet owners.

The most common types of pet supplements are:

  • Products offering additional nutrients such as vitamins, minerals, trace elements, or a combination of these, often in powdered form. These are typically intended to be fed alongside a diet that is not complete (e.g. home-made food) with input from an experienced animal nutritionist or veterinary nutritionist who can formulate a balanced diet.  The use of these supplements must be carefully considered to avoid nutritional imbalances and excesses.
  • Products containing functional ingredients (offering a wide range of health benefits, available in a whole array of dry, moist, or semi-moist formats)
  • Snacks and treats that are aimed for training or simply bonding between the owner and their pet.

Where a supplement is marketed suggesting a particular benefit, then it is prudent to examine the clinical evidence for its use, and to ensure that its addition will not upset the balance of nutrients in the main diet. Manufacturers should be able to provide this information or direct you to published data that backs up their product claims.


What are functional foods or functional ingredients?

These (also known as nutraceuticals) are components of certain foods that can offer specific health benefits if they are consumed on a regular basis as part of an appropriate diet.[1] Depending on their use and the species of animal, these could belong to prebiotics, probiotics, antioxidants, essential fatty acids, dietary fibre, some vitamins and minerals, etc. Some functional foods are better studied, and their effectiveness are well-established, while other (more novel) ingredients need more species-specific research to be better understood.

An example of beneficial functional ingredients could be the use of nutrients that can act as antioxidants or anti-inflammatory agents to help regulate or improve an animal’s immune response to a certain disease.[2]


Do complete diets need supplementation?

Generally, for a healthy cat or dog, it is not recommended to supplement a ‘complete’ diet with products predominantly containing vitamins, minerals, or trace elements. This is because a complete product is designed to deliver the correct balance of nutrients required for the life-stage of the species it is intended for.

This balance is particularly important because, just as deficiencies can cause health problems, excess of certain nutrients could also be harmful for pets. For example, too much of some vitamins or minerals could be toxic or challenge the animal’s ability to regulate important bodily functions. Providing calcium supplements, for instance, to growing puppies that are already on a balanced diet, can damage their skeletal growth and development.[3]

However, even for animals being fed complete foods, there are occasions when supplements may be beneficial. 

For example, long haired breeds of dogs and cats may require slightly higher essential fatty acid intakes to maintain optimal skin health and hair quality. In this case, an essential fatty acid supplement, or using a complete diet that offers this, could be beneficial.[4]


How about treats and snacks with health benefit claims?

As highlighted above, pet supplement as an umbrella term, covers the vast array of snacks and treats designed to help with the management of certain issues that can develop during a pet’s lifetime (e.g. dental, joint, skin and coat or digestive problems).  In the pet world these supplements are routinely provided in a convenient and palatable snack/treat format rather than powdered or pelleted forms as seen in the farm animal feed market. 

With treats and snacks, it is important to carefully consider nutrient and energy provision of these products, on top of the main complete diet. Complementary products should not make up more than about 10% of the individual pet’s daily calorie intake. This 10% rule will reduce the risk of undersupplying important nutrients (which should from the main complete food) and/or overfeeding too many calories!


Do small mammals and pet birds need supplements?

For some small mammals and pet birds, not all product formats are complete in which case additional products or supplements may be needed or recommended by manufactures. This information should be given as part of the product’s feeding guidelines. Given the diverse range of small furry and feathery pets, and their unique physiological needs, we recommend referring to PFMA factsheets on Pet Birds, and small mammals for more specific information.


The verdict

Where a complete food is being fed to an animal, this should be sufficient to meet their nutritional requirements for the life-stage the diet is intended for. However, in addition to essential nutrients, there are other (functional) ingredients that can offer additional health benefits. Try and look for scientific evidence that supports product claims.

Always follow the feeding guidelines of pet food products and if you are unsure, contact the manufacturer’s helpline for more information. A veterinary nutritionist should be consulted in case of any clinical conditions (your vet will be able to refer your pet to a specialist if needed).

To see our diverse range of evidence-based pet nutrition topics, suitable for displaying at pet shops and veterinary practices, please check PFMA Factsheets and Posters.






  Cortese, L., Annunziatella, M., Palatucci, A.T., Lanzilli, S., Rubino, V., Di Cerbo, A., Centenaro, S., Guidetti, G., Canello, S. and Terrazzano, G. (2015) An immune-modulating diet increases the regulatory T cells and reduces T helper 1 inflammatory response in Leishmaniosis affected dogs treated with standard therapy. BMC Veterinary Research, 11(1), p.295.

  Di Cerbo, A., Morales-Medina, J.C., Palmieri, B., Pezzuto, F., Cocco, R., Flores, G. and Iannitti, T., (2017) Functional foods in pet nutrition: Focus on dogs and cats. Research in veterinary science, 112, pp.161-166.

  Fediaf (2019) Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs.

  Goldy GG, Burr JR, Langardener CN. (1996) Effects of measured doses of vitamin A fed to healthy beagle dogs for 26 weeks. Vet Clin Nutr.3:42-49.

  Hazewinkel HAW, Hackeng WHL, Bosch R, et al. (1985) Influences of Different Calcium Intakes on Calciotropic Hormones and Skeletal Development in Young Growing Dogs. In: Comparative Pathophysiology of Regulatory Peptides. S. Karger AG. 17 p. 221-232.

  Schoenmakers I, Hazewinkel HAW, Voorhout G, et al. (2000) Effect of diets with different calcium and phosphorus contents on the skeletal development and blood chemistry of growing Great Danes. Vet Rec. 147(23):652-660.

  WSAVA Global Nutrition Committee (2018) Frequently asked Questions and Myths.


[1] Di Cerbo et al. (2017)

[2] Cortese et al. (2015)

[3] Fediaf (2019)

[4] WSAVA Global Nutrition Committee (2018)

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