Nutritional Supplements: What are they and does your dog need them?

What are supplements?

A nutritional supplement is a concentrated ingredient (e.g., vitamins, minerals, herbs, amino acids) believed to provide some type of health benefit, usually when taken orally or added to food.

Are supplements tested?

Supplements are not regulated by the FDA because they are not considered food or medication. Therefore no testing for safety, efficacy, or quality are required. As a result, not all supplements have undergone rigorous (or any) testing. Even those companies that claim to have done clinical trials may not have published the results or used rigorous scientific methods to assess their products.

Does my dog need nutritional supplements?

Most dogs do not need supplements. Commercial dog food that is based on AAFCO guidelines is balanced and has all the nutrients most dogs need to thrive. Companies that go a step further and conduct feeding trials on their products have tested their food on multiple dogs for at least 6 months, monitoring the dogs’ responses and health throughout the entire trial period.

When to use supplements

If you are preparing a homemade diet for your dog, you will likely need to add supplements. You should consult a veterinarian, a veterinary nutritionist, or a service such as BalanceIt in order to  help you determine which additional nutrients your dog needs for a complete and balanced diet. 

If your dog has a vitamin deficiency or a specific health problem, your veterinarian may recommend supplements that have been demonstrated to help (or not worsen) a condition. Older pets can have age-related issues, such as a reduced ability to absorb nutrients or resist infections. Some supplements may help reduce the impact of the degenerative effects of aging. 

Supplements may take several weeks to take effect, so be sure to follow instructions from your veterinarian or the product manufacturer. Monitor your pet closely during this trial period to ensure any new ingredients agree with your pets’ tummy.

How do I know if a supplement is a good quality product?

Veterinary Nutritionist Dr. John Bauer proposed the acronym PETS to describe four key features of a supplement to assess before you give it to your dog.

• Product quality: The purity and quality of listed ingredients, and avoidance of contaminants
• Efficacy: Has the product been tested for efficacy in dogs? At what dose? Were the studies peer-reviewed?
• Tolerance: Is the supplement easy to administer and acceptable to your dog? Are there possible side effects? 
• Safety: What safety data is available about the supplement?

These guidelines can help you compare products and brands, and avoid products that might be harmful.

Potential adverse effects

Always let your veterinarian know what supplements you are giving your dog, even if they did not recommend or prescribe them. Not all supplements are safe or tested for efficacy and some may interact or interfere with other medications, or may even be harmful for some conditions. 

Because of the lack of regulation, it is also possible that some supplements contain contaminants such as mercury or lead. 

Nutritional supplements: Use good sense about using them

There may be very good reasons to give your dog supplements. Your veterinarian can provide you with guidance on your dog’s needs. However, if a supplement does not offer any benefits to your dog, it is potentially a waste of your money – money that could be spent on other aspects of your dog's health!

• Multivitamins: A multivitamin is a combination of vitamins, minerals and other nutrients. There are several different formulations on the market. If your dog is eating a balanced diet that is appropriate for dogs and your dog’s life stage, it is unlikely that multivitamins will be helpful, and in some cases, they may be harmful.
• B vitamins: A B complex is considered generally safe for most dogs as they will excrete excess through their urine, however most dogs do not need supplementation. It may be recommended for older dogs to help with decreased appetite or fatigue. Dogs with gastrointestinal disease may be prescribed B12 (cobalamin) supplements.
• Glucosamine and chondroitin: Glucosamine is believed to have anti-inflammatory properties, and chondroitin may help prevent the deterioration of cartilage. Unfortunately, there have been few well-designed studies, and to date there is no evidence of their effectiveness in alleviating the signs of osteoarthritis. Some medications may interact with glucosamine/chondroitin supplements. Anti-inflammatory medications such as NSAIDS are more effective at treating arthritic pain.
• Probiotics: Probiotics contain microorganisms (such as bacteria and yeast) that may be recommended for dogs with gastrointestinal disease or signs. Some research has pointed to improvements in stool consistency for dogs given probiotic supplements, but overall the body of research is limited by small sample sizes and lack of appropriate controls.
• Omega 3 Fatty Acids: Fatty acids have anti-inflammatory properties and are among the most well-studied supplements for pets. Evidence suggests Omega-3 supplements may help dogs with osteoarthritis, and they can promote heart and skin health. Fish oil is the most appropriate form, as other forms (such as from flaxseed) may not be properly absorbed. Omega 3 fatty acid supplements may not be great for dogs with sensitive stomachs, as they can cause vomiting and diarrhea, especially at high doses.
• Lecithin: Lecithin is a mixture of fats that is naturally occurring in many food items, such as eggs, vegetables and meat. One study of lecithin supplementation for dogs found no changes to any components of several blood tests, although owners reported less “skin exfoliation” for dogs who received the supplement. More research is needed.
• Antioxidants (e.g., Vitamins C & E, Coenzyme Q-10, Alpha Lipoic Acid): There are several antioxidants, including vitamins, minerals, enzymes, and herbs. The defining feature is that they are believed to protect cells from damage.They are primarily recommended for animals experiencing chronic inflammation, such as from allergies and arthritis. Research also suggests that antioxidants may offer dogs some protection against cognitive decline caused by aging. More research is needed to understand the potential benefits of antioxidants. Many pet foods now also include antioxidants as a part of their formulation.
• Cranberry extract: Cranberry extract is an herbal remedy which some humans take to prevent urinary tract infections (UTIs). The evidence for the efficacy of cranberry extract in humans is far from conclusive, and the clinical studies in dogs have also had mixed results. One study found that more dogs who received cranberry extract developed UTIs than dogs who received a placebo. 

Supplements for breeding

When bitches have adequate caloric intake of a complete and balanced dog food, there is no need for supplementation. Your reproductive veterinarian can help you make any decisions related to your breeding dogs, and help you assess any new research related to supplements and nutrition.

• Calcium: Calcium supplementation is not recommended during pregnancy because calcium excess can impact hormone production by the parathyroid and cause eclampsia. This means that Calcium supplementation during pregnancy can cause hypocalcemia (low calcium levels) and postpartum eclampsia. Your reproductive veterinarian can advise you as to whether your bitch would benefit from postpartum calcium supplementation.
• Folic acid (B9): Previous research has suggested that maternal supplementation of folic acid may reduce the incidence of cleft palates in brachycephalic and small breed dogs (e.g., Chihuahuas, Pugs), but a recent large-scale study of Golden Retrievers and Labradors found no such benefits. 

Resources

AVMA: Assessing pet supplements Use widespread in dogs and cats, evidence and regulation lacking

Cummings Veterinary Medical Center at Tufts University: Dietary Supplements for Pets: Harmful or Helpful?

DVM 360: Joint supplements for dogs: The helpful vs. the hype

The National Academies: Safety of Dietary Supplements for Horses, Dogs, and Cats

VCA: Supplements - Selecting Supplements for your Pet

Bauer JE (2001) Evaluation of nutraceuticals, dietary supplements, and functional food ingredients for companion animals. J Am Vet Med Assoc 218(11): 1755–60

Domoslawska, A., Jurczak, A., & Janowski, T. (2013). Oral folic acid supplementation decreases palate and/or lip cleft occurrence in Pug and Chihuahua puppies and elevates folic acid blood levels in pregnant bitches. Polish Journal of Veterinary Sciences, 16(1).

Finno, C. J. (2020). Veterinary Pet Supplements and Nutraceuticals. Nutrition today, 55(2), 97.

Gonzales, K. L., Famula, T. R., Feng, L. C., Power, H. M. N., & Bullis, J. M. (2021). Folic acid supplementation does not decrease stillbirths and congenital malformations in a guide dog colony. Journal of Small Animal Practice, 62(4), 286-292.

Greco, D. S. (2009). Nutritional supplements for pregnant and lactating bitches. Topics in companion animal medicine, 24(2), 46-48.

Harvey, N. (2011). Commonly used dietary supplements in canines. The Veterinary Nurse, 2(1), 26-33. https://doi.org/10.12968/vetn.2011.2.1.26 

Magalhaes, T. R., Lourenco, A. L., Gregorio, H., & Queiroga, F. L. (2021). Therapeutic Effect of EPA/DHA Supplementation in Neoplastic and Non-neoplastic Companion Animal Diseases: A Systematic Review. in vivo, 35(3), 1419-1436. https://iv.iiarjournals.org/content/35/3/1419