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Vitamin D deficiency & critical illness: is your dog at risk?

Posted on: May 8, 2018   by  Vitamin D Council


Ever wonder whether founder and President of the Vitamin D Council, Dr. Cannell, supplements his dog with vitamin D? Here is his regimen:

“For the last five years, I have given my 12-pound dog, Prozac, 25 mcg (1,000 IU) of vitamin D per day. I did this after inspecting dog food containers only to discover that few manufacturers add extra vitamin D to dog food. It does have a tiny amount of vitamin D that comes from the meat and fish products in dog food. Dogs cannot make vitamin D in their skin; they have traditionally got it from their prey meats. I do not know if it has helped; I mean, how do I know what didn’t happen? I do know Prozac has not been sick for the six years I’ve had him.”

The bond between people and dogs

Dogs have been coined man’s best friend for centuries. These animals offer a unique form of support and companionship compared to other species. In fact, research shows that dogs can read facial expressions, have empathy, feel emotions such as love, shyness, joy, anger, fear, jealousy, disgust, contentment, distress and excitement. Dogs will even feel grief over a loss, such as when a human or animal companion dies.

Furthermore, owning a dog may help reduce stress, promote relaxation, encourage physical activity and is associated with an increased life span.

Canine health risks

As pet owners, we do our best to ensure our trusted companions receive the love and care they need to thrive. But, what happens when your dog becomes ill, despite your best efforts? Unfortunately, this reality is all too common for pet owners.

Dogs are prone to many of the same acute and chronic illnesses as people. However, since our pets can’t tell us when they feel sick, it is not uncommon for some diseases to go unnoticed, potentially leading to critical illness.

Nutrition status, weight and physical activity can significantly affect treatment outcomes in ill dogs. In addition, research suggests vitamin D may play a role in various canine diseases. However, until recently, researchers have yet to evaluate how vitamin D deficiency my affect critical illness outcome in dogs.

New research on vitamin D and canine critical illness

In a study published earlier this year, researchers hypothesized that, like humans, critically ill dogs are more likely to be vitamin D deficient, and that vitamin D deficiency may affect disease severity and survival. A total of 99 dogs were included in the study, 82 of which were admitted to the University of Missouri Veterinary Health Center Intensive Care Unit (ICU) between October of 2016 and January of 2017 for critical illness. The remaining 17 healthy dogs served as healthy controls.

The researchers evaluated the dog’s physical health, lab values (including 25(OH)D levels) and disease severity within 24 hours of admission. They recorded overall length of hospital stay, reason for ICU admission and survival outcomes. In addition, the researchers followed up with each dog owner to determine survival a day after discharge and again 30 days after discharge from ICU.

Here is what the researchers found:

    • Healthy dogs had significantly higher vitamin D levels than dogs who were critically ill or had sepsis (p = 0.001 and p = 0.002, respectively).
    • Vitamin D status was an independent predictor of survival, both in-hospital and after 30 days (p = 0.01 and p = 0.001, respectively).
    • Every 1 ng/ml increase in 25(OH)D levels was associated with a 6% decreased risk of mortality (OR: 1.06 (1:00-1:13); p = 0.046).
    • Every 1 ng/ml increase in 25(OH)D levels was associated with a 5% decreased risk of mortality 30 days after being discharged (OR: 1.05 (1.00-1.10); p = 0.03).
  • Higher vitamin D status was associated with lower illness severity (p = 0.001), but not with ICU length of stay.

The researchers concluded,

“Hospitalized dogs with critical illness have decreased serum 25(OH)D concentrations compared to healthy dogs and can be used to predict survival in this cohort.”

Final thoughts

These findings suggest vitamin D may plays a key role in illness severity and treatment outcomes among critically ill dogs. Unfortunately, research about how vitamin D may affect canine health is still in its infancy. There is a lack of research evaluating the ideal dose of vitamin D for dogs, so it is difficult to determine what the ideal 25(OH)D reference range for dogs is at this time.

Until research suggests otherwise, we hypothesize vitamin D metabolism among dogs is similar to humans, and thus dogs need about 100 IU/kg body weight. For example, Several years ago Dr. Cannell wrote on a study that found toxic doses were similar among humans and dogs.

Dr. Cannell stated,

“Again, I don’t know if vitamin D has helped Prozac. Remember, we usually cannot know, from personal experience, what did not happen. My dog is a healthy, curious, alert, and joyful creature but that’s true of plenty of dogs who don’t take vitamin D. Genetically, dogs are more similar to humans than they are different. It’s likely vitamin D plays as important a role in canine health as it does in human health.”

Do you have any questions or experiences about vitamin D and canine health you would like to share? If so, please reach out to our team at [email protected]


Sturges, M. & Cannell JJ. Vitamin D deficiency & critical illness: is your dog at risk?The Vitamin D Council Blog & Newsletter, 4/4/2018.


Jared A. Jaffey, Robert C. Backus, Kaylyn M. McDaniel, Amy E. DeClue. Serum vitamin D concentrations in hospitalized critically ill dogs. PLoS ONE, 2018.

3 Responses to Vitamin D deficiency & critical illness: is your dog at risk?

  1. [email protected]

    Many studies of the vital importance of Vitamin D for healthy dogs, farm animals, etc,
    Dogs used to have adequate levels of vitamin D
    It used to be that only 1% of dogs died of cancer
    Now 50% die of cancer
    Every single dog which died of cancer had low vitamin D levels – look at the chart!

  2. Ron Carmichael

    I’ve long advised patients with dogs and cats to consider the oral drops for them. Recently my daughter was told by a vet that vitamin D can be fatal in cats, but I don’t find much in the literature and they didn’t cover this in pharmacy school. Any advice for feline owners? I can testify that my cat became so enamored of the D drops it would wake us, beg for it, and offer its paws on the counter – I would put a drop on the top of a paw and it would strongly lick the paw to get all the D.

  3. Peter Parsons

    Thanks for this important article. One statement was a real eye-opener, that which said dogs cannot make Vit D in their skins. So our pups are just enjoying the warmth during their sun Baths? I guess we now go the supplement route.

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