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Why Vitamin D Is Important for Pets

Posted: 12/27/2022 | BY: Erin Cain | Categories: Uncategorized

The vitamin D that we all know and love is vital for our health, but it also plays an integral role in the health of our pets. Pet parents need to make sure their pet has enough vitamin D in their body. Let’s explore why vitamin D is important for pets and how to best care for your pet’s vitamin D levels.

A collie stands in the sunshine.

What is Vitamin D?

Vitamin D is a hormone that promotes calcium absorption. It is considered an essential hormone or vitamin for overall health and wellness. In human health, it’s called the “sunshine vitamin” because of its production in response to UV exposure. Pets can also obtain this nutrient from foods such as eggs and certain fish oils.

A recent human study suggests that vitamin D may be even more important for bodily health than previously thought. It can help prevent disease, treat illness with greater effectiveness and fewer side effects, prevent complications from pharmaceuticals, and boost immunity against infection. Since pets can experience those benefits, too, Vitamin D in appropriate amounts can make a significant difference in their health.

Vitamin D is important for your pet’s bone health because, unlike herbivores and omnivores, dogs and cats cannot synthesize Vitamin D through their skin due to their fur coats and oily skin; thus, pets must obtain their Vitamin D from their dietary sources. A Vitamin D deficiency can lead to serious health problems, and for puppies, it can result in rickets. In this condition, the bones are soft and brittle, and the legs become bowed.

The body uses vitamin D to maintain bone health by controlling the absorption from foods, moving calcium around in and out of the bloodstream, and excreting it through the kidneys if too much accumulates frequently. Insufficient levels can lead pets, particularly cats, at higher risk for heart failure and other disorders. Additionally, research finds a link between Vitamin D and the prevention of cancers, so the correct amount in your pet’s diet could help her avoid this debilitating and deadly disease.

Egg yolks in a bowl.

What does Vitamin D do for pets?

Vitamin D is a nutrient obtained through UV light exposure (Vitamin D2); however, Vitamin D3, or cholecalciferol, is found in plant and animal products. The most common food sources of Vitamin D3 for cats and dogs are egg yolks, liver, beef, fish, and dairy. Because Vitamin D3 is a fat-soluble vitamin, both cats and dogs can store it in their fatty tissue, liver, and muscles. Then, excess Vitamin B3 is moved to the liver and bloodstream.

Vitamin D helps your pet’s body absorb calcium. It also prevents osteoporosis, muscle weakness, and diabetes. Also, recent studies have found it can alleviate autoimmune conditions. Vitamin D helps inflammatory bowel disease (IBD) and aids chemotherapy treatment in cancer patients.

Because pets require specific amounts of Vitamin D — and the amounts may depend on species, breed, and age — diet is considered the best source of Vitamin D for pets. Unfortunately, not all commercial pet foods provide adequate amounts of this vitamin in their foods. Some pet food companies have recalled dog food because it had excess amounts of Vitamin D, which made pets severely ill after consuming it. In one instance, the Food and Drug Administration (FDA) found pet food containing 70 times the amount of acceptable Vitamin D levels.

Speak with your veterinarian or an animal nutritionist to ensure that your cat or dog gets the right amount of Vitamin D in her diet. Those two sources will help you determine which diet is right for your pet if dietary changes are required.

An orange cat lounges by the window.

What are the dangers of low Vitamin D levels?

Without an adequate amount of Vitamin D, dogs and cats become susceptible to various medical issues and the potential development of illnesses or diseases. The lack of vitamin D in pets can range from mild to life-threatening symptoms, depending on how much calcium they lack. Without enough Vitamin D and calcium, their bones become brittle, which could lead to further problems like osteomalacia (brittle bone disease) or rickets; this lack will also hamper muscle function.

A lack of vitamin D in dogs can increase the risk for heart complications and cancer. One study found that when a dog doesn’t get enough Vitamin D, it becomes more likely to face serious illnesses like congestive heart failure, which will ultimately lead to death. Likewise, for cats, the danger of Vitamin D deficiency may result in chronic kidney disease and kidney failure.

What are the symptoms of Vitamin D deficiency?

There are signs and symptoms of Vitamin D deficiency that will appear in pets with low levels of this critical vitamin. Here are the symptoms to look for:

  • loss of appetite
  • fatigue
  • weight loss
  • diarrhea
  • joint pain
  • limited mobility
  • increased thirst
  • excessive drooling
  • brittle bones
  • stunted growth
  • decreased muscle mass
  • depression
  • neurological abnormalities
  • kidney stones
  • bone pain
  • cardiac arrhythmias

Any one of these symptoms in your pet should prompt a vet visit to determine if these medical issues are related to a lack of Vitamin D.

While Vitamin D supplements are available for pets, never treat your dog or cat yourself without discussing guidance with your veterinarian. An overdose of Vitamin D can lead to deadly consequences.

A puppy walks along a beach.

Can a pet have too much Vitamin D?

Too much Vitamin D in a dog or cat’s body can result in severe medical issues and may, in rare cases, lead to fatality. Excess vitamin D can lead to too much calcium, which is dangerous because this toxicity affects a pet’s kidneys, muscles, cardiovascular system, and gastrointestinal tract. In dogs, large enough amounts of this nutrient will cause kidney failure within a matter of days.

Although most Vitamin D poisoning comes from a pet diet too high in Vitamin D, accidental overdose can also occur if dogs get into their pet parents’ prescription drugs or commercial rodent poisons that contain bromethalin.

Symptoms of Vitamin D toxicity include:

  • anorexia
  • frequent and uncontrollable urination
  • excessive drooling
  • muscle weakness
  • vomiting with blood
  • excessive thirst
  • tremors
  • convulsions
  • black or bloody stools
  • lethargy
  • abdominal pain

As with Vitamin B deficiency, should your pet exhibit these signs, take her to the veterinarian as soon as possible. Your vet will examine and perform a blood test on your pet which will show Vitamin D levels, and your pet’s treatment plan will start from there.

Does pet insurance cover Vitamin D health issues?

Frequent veterinary visits for Vitamin D deficiency or toxicity and Vitamin D supplements for pets with rickets or brittle bones are necessary but costly care. Now, suppose your pet has a pet health insurance plan. In that case, a significant amount of office visits, supplements, medications, and other treatments will be covered and reimbursed to you. That way, you can worry about what’s most important: your pet’s health.

Pet Insurance Review has the best health insurance plans for your pet’s needs and your budget. Ensure that your pet has the best health care possible, and get a free pet insurance quote today.




1. Scott, D. (2021). New Study Shows Dogs with Low Vitamin D Are At Risk for Cancer. Retrieved from

2. Katz, B. (2018). Excessive Vitamin D in Pet Food May Be Making Dogs Sick. Retrieved from

3. Barber, E. (2019). Your Dog Needs Vitamin D, But Too Much Can Be Toxic. Retrieved from

4. Davidson, B. (2020). Do Dogs Need Sunlight for Vitamin D? Retrieved from

5. Hines, R. (2021). Why Are My Dog or Cat’s Vitamin D3 Levels Too Low or Too High? Retrieve from


The information contained on this blog is intended for informational and educational purposes only and should not be construed as medical advice. It is not a substitute for professional veterinary care. Always consult with your veterinarian before making any changes to your pet's health care or treatment plan.

The authors of this blog are not veterinarians and do not claim to be experts in pet health. The information provided here is based on our own experiences and research, as well as information from reputable sources. However, we cannot guarantee the accuracy or completeness of this information.

We encourage you to do your own research and consult with your veterinarian before making any decisions about your pet's health.

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