Should A Dog’s Diet Be Supplemented With Vitamin C?

Most of us are familiar with vitamin C and its health benefits for people.  Vitamin C has been proven to have powerful immune system boosting properties to help to prevent infectious disease and cancer.  Vitamin C is also a biological sponge, that is, it has molecular properties capable of binding to free radicals that form in the body every moment of our existence and eliminating them from the body.

Free radicals are charged ions and compounds that damage tissues and organs via a chemical process called oxidation.  They form as the result of physical stress on the body, mental stress, and as the result of age.  When we take vitamin C and other vitamins known to be “antioxidants,” these compounds effectively bind, neutralize, and facilitate the removal of free radicals, thereby protecting the body from disease and slowing the aging process.

It should necessarily follow that we should administer vitamin C to dogs as well, right?  They are after all, physiologically built very similarly to us and suffer many of the same disease processes, as well as experience the gradual break down of their bodies from father time.  However, when it comes to vitamin C, they are quite different.

The major difference between people and dogs when it comes to vitamin C is that people necessarily depend on outside supplementation of vitamin C either through dietary sources (such as oranges and other fruits) or supplements.  This is because we possess a very poor ability to synthesize our own vitamin C.

Dogs, on the other hand, are physiologically quite capable of synthesizing their own endogenous vitamin C.  Having this ability, under normal circumstances, as long as they are fed as nutritionally well balanced diet, they do not require outside supplementation with vitamin C.

For some of you that are particularly well informed, you may know that vitamin C is a water soluble vitamin and, as such, it has little potential to cause toxicity (excesses in water soluble vitamins are easily eliminated by both dogs and people).  If this is what you are thinking, you are correct.  You may also be thinking that if this is the case, what harm would there be to offer your dog a little extra vitamin C?  The answer is that that for an adult dog, other than a mild, self limiting case of loose stools, there really is no harm.

For growing puppies, on the other hand, there is great potential for harm.  Vitamin C has the potential to cause spikes in serum calcium.  In response to this, the body activates a hormone called calcitonin that interferes with the proper development of bone density and proper remodeling of a puppy’s skeletal system as they grow.  This is especially true in large breed puppies.  As such, I generally advise against supplementing a puppy’s diet with vitamin C.

Still, although dogs do effectively synthesize their own vitamin C, there are certain conditions where it is beneficial to prescribe additional supplementation with vitamin C.  Female dogs that suffer from chronic recurring urinary tract infections is one case example that I would  recommend supplementation with vitamin C.  In this case, vitamin C not only directly boosts the immune system both locally and systemically to fight infection, as a water soluble vitamin eliminated primarily via the kidneys, vitamin C also acidifies the urine directly to create a less hospitable environment for bacteria to proliferate.

In the case of any pet under treatment for cancer, I also recommend supplementation with vitamin C.  Cancer in the body creates systemic free radicals that vitamin C helps to eliminate.  Boosting the immune system with vitamin C helps to prevent secondary infection dogs are predisposed to when under treatment with chemotherapy.  Boosting the immune system also aids the dog’s immune system to fight the cancer itself.

As a general rule, vitamin C is not necessary for healthy dogs fed a nutritionally balanced diet.  It is potentially harmful to supplement puppies with vitamin C.  However, there are specific health circumstances where supplementation with vitamin C is beneficial to dogs.  Be sure to discuss with your veterinarian before considering any nutrient supplementation regimen for your dog.

Dr. Roger Welton is a practicing veterinarian and highly regarded media personality through a number of topics and platforms.  In addition to being passionate about integrative veterinary medicine for which he is a nationally renowned expert, Dr. Welton was also an accomplished college lacrosse player and remains to this day very involved in the sport.  He is president of Maybeck Animal Hospital , runs the successful veterinary/animal health  blogs Web-DVM and Dr. Roger’s Holistic Veterinary Care, and fulfills his passion for lacrosse through his lacrosse and sport blog, The Creator’s Game.