Vitamin D Toxicity in Dogs

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All dog parents know that there are some things your canine pal definitely shouldn’t eat, like chocolate, for example. But did you know that an excess amount of certain vitamins can actually be dangerous to your dog’s health?

Vitamin D is one such example. Generally, vitamin D is an important nutrient for your dog, because it helps them retain calcium and regulate the balance of phosphorus in their bones. In fact, a lack of vitamin D can cause weak, soft bones, so it’s especially important that puppies get enough vitamin D in their diet.

However, there is such a thing as too much vitamin D, which can be toxic for our canine companions. Since it’s a fat-soluble vitamin, any excess amount that remains in the body won’t be easily excreted in a dog’s urine. What happens instead, is that it gets stored in their liver and fat tissue. Therefore, high levels of vitamin D in a dog’s body can cause kidney failure and even death if left untreated.

Another result of a dog getting too much vitamin D is a dangerously high level of calcium in the blood. Although vitamin D is vital for bone health, too much of it in the blood can be extremely damaging to various internal organs, such as the heart and gastrointestinal tract. A dog that has ingested too much vitamin D is also at risk of developing calcium stones or calcium deposits in various soft tissues throughout their body. This can prevent organs from functioning properly and can even cause organs to stop functioning altogether.

Here, we’ll take you through the causes, symptoms, treatment, and prevention methods when it comes to vitamin D poisoning and your dog. Keep reading to learn more.

What is Vitamin D?

You might have heard of vitamin D being referred to as the “sunshine vitamin” for us humans, because our bodies have the unique ability to create this essential vitamin when sunlight hits our skin. The sun’s UV rays interact with a protein in our skin, called 7-DHC, which creates vitamin D3 — the active form of vitamin D.¹

This vitamin is just as essential for dogs, but unlike us, our canine friends are unable to make vitamin D in their skin from sunlight. This means that they must rely solely on their diet to get enough vitamin D. As mentioned earlier, vitamin D helps dogs to retain calcium for bone health. It’s also necessary to help maintain a perfect balance of calcium and phosphorus levels in the blood. Additionally, vitamin D plays a number of key roles on a cellular level, helping to modulate immune, muscle, and cardiovascular functions.²

Most commercially available dog food contains controlled amounts of vitamin D. In the United States, this is regulated by the American Association of Feed Control Officials (AAFCO). Their regulations state that every kilogram of dog food should contain at least 500 international units (IU) of vitamin D. The maximum amount allowed in dog food is 3000 IU per kilogram of food³.

Fish and other seafood oils are well-known sources of vitamin D, so it’s often added to dog food to help meet these numerical requirements. Many pet food manufacturers will exceed the minimum amount to ensure that your pet gets enough vitamin D.³ It’s especially important that puppies get enough vitamin D in their diets from the beginning, as a deficiency can cause soft bones and growth problems. However, no dog should have more than 100-120 mg per day. This exact amount may vary depending on a dog’s size and weight.

List of causes of vitamin D poisoning in dogs

What Causes Vitamin D Poisoning in Dogs?

There are a few ways that dogs may get too much vitamin D:⁴

  • Eating vitamin D enriched dog food. Keep a close eye on your dog’s portion sizes if you feed your dog this kind of food. You should also ensure that they can’t access their food outside of mealtimes.
  • Ingesting vitamin D supplements or creams meant for human consumption or use. Always store your own vitamin D-based products in a place where your dog can’t access them, accidentally.
  • Ingesting certain rodent-killing chemicals (rodenticides). The chemical term for vitamin D produced by animals is cholecalciferol, some rodenticides contain this ingredient. All rodenticides and pesticides should be kept away from your pet.
  • Ingesting certain plants, fungi, and yeasts that produce high amounts of ergocalciferol or vitamin D2. Many dogs like to eat grass and plants, so keep an eye on your dog if you go for walks in areas with a lot of vegetation.

Contact your vet immediately if you suspect that your dog may have vitamin D toxicity. The following section will take you through the signs and symptoms to look out for.

List of signs of vitamin D poisoning in dogs

Signs of Vitamin D Poisoning in Dogs

As a dog owner, you always try your best to ensure your dog’s health and safety, but accidents happen. Dogs who have consumed too much vitamin D may experience any of the following symptoms⁴ ⁵

  • Gastrointestinal distress (including vomiting, diarrhea, and dark, tar-like stools)
  • Loss of appetite
  • Excessive urination and/or drinking more
  • Weight loss
  • Excessive drooling
  • Abdominal pain
  • Muscle tremors or twitching
  • Seizures

Typically, symptoms of vitamin D toxicity develop within 12-36 hours after ingestion, but it’s important to be aware of the fact that vitamin D poisoning from food may develop more slowly over time.⁶ Your vet will be able to give you the best food recommendations that fit to your dog’s specific nutritional needs.

What to do if Your Dog Has Vitamin D Poisoning

So, what do you do if your dog accidentally ingests too much vitamin D? The best thing to do is seek medical attention from a veterinarian. You can also call the poison control emergency vet hotline at (888) 426-4435 or visit an emergency vet clinic if your dog has severe symptoms⁷.

Only a vet will be able to definitively diagnose vitamin D toxicity in your dog. First, they will evaluate your dog’s symptoms. They will likely ask you questions about the kind of food your dog is eating and if there are any vitamin D-containing products in your home that your dog may have gotten into.⁴

Next, they may take a blood sample in order to accurately determine the calcium, phosphorus, and vitamin D levels in your dog’s blood. A urine sample may also be necessary to assess your dog’s kidney function, since too much vitamin D can damage the kidneys significantly. Depending on these results and the severity of vitamin D toxicity, your vet will determine the best course of treatment to get your dog feeling healthy again.⁴ Make sure to schedule a follow-up appointment with the vet to ensure that your dog is fully recovered after treatment.

Tips to prevent vitamin D poisoning

Vitamin D Toxicosis Treatment & Prevention

The specific course of treatment will vary, depending on the severity of a dog’s vitamin D toxicity as well as their breed, age, weight, and other general health factors. The main goal is always to remove the source of excess vitamin D, whether it’s food or easy access to other vitamin D products. This is important in order to prevent further exposure and to flush the excess vitamin D out of the dog’s system. Sometimes, IV-fluids may be necessary to facilitate this process.⁴

In less severe cases, a vet may recommend a simple change of diet. They might also prescribe medication to help alleviate symptoms, such as steroids, anti-nausea medication, antacids, and calcium or phosphorus-reducing medication. It’s also likely that the vet will need to continue monitoring the dog’s blood calcium and phosphorus levels until the values are back down to normal.⁴

Here are some steps you can take to help prevent your dog from getting vitamin D poisoning:

  • Pay attention to any dog food recalls. Take a picture of the label, serial number, and expiration on the bag, or better yet, store dog food in its original bag. All pet food manufactured in the United States has an FDA code, which can prove very useful if your dog gets vitamin D toxicity from their food.
  • Always keep vitamin D-rich products (supplements, powder, pills, creams, etc.) out of reach.
  • Don’t expose your dog to rodenticides — including animals that may have ingested rat poison.
  • Ensure that your dog stays away from any vitamin D-rich plants.
  • Contact your vet or emergency vet services immediately if your dog starts showing signs consistent with vitamin D poisoning.

Taking these steps to ensure your dog’s safety will lower the chances of them accidentally ingesting too much vitamin D.

FAQs

How much vitamin D is toxic to a dog?

Every dog is different. Symptoms of vitamin D toxicity can be seen with doses as low as 0.1 mg per kilogram. A lethal dose for a mature dog is about 2 mg per kilogram.⁸

How long does it take for a dog to show signs of vitamin D poisoning?

Usually 12-36 hours, but it can take longer if the excess vitamin D comes from a dog’s food.

Can a dog recover from vitamin D poisoning on their own?

No. If you think your dog might have consumed excessive amounts of vitamin D, contact emergency vet services or the pet poison control hotline at (888) 426-4435 as soon as possible. If left untreated, vitamin D poisoning can be fatal.

Woman smiling with small dog in lap; both looking at laptop during online vet consultation

Final Notes

Vitamin D plays a key role in your dog’s overall health, but too much can have severe health consequences. Always make sure that your dog can’t accidentally get into your vitamin D supplements or rodent-killing chemicals, if you have them. Keep up to date on the latest pet food recalls and immediately stop feeding your dog a recalled brand or type of food. Some plants are rich in vitamin D, which can cause overexposure if your dog licks them. Avoid walking outside in areas where such plants might be present. If your dog shows signs of vitamin poisoning, contact emergency veterinarian services right away.

Feeling unsure about vitamin D and your dog? Talk to a Dutch vet. Dutch offers non-emergency vet consultation services to help you navigate dog ownership safely and with confidence. Whether you’re wondering what kind of food to give your precious pooch or what to look out for in an emergency, Dutch can help answer any questions or concerns you may have.

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References

  1. McNeill, Anne  Marie, and Erin Wesner. “Sun Protection and Vitamin D.” The Skin Cancer Foundation, 14 Mar. 2019, www.skincancer.org/blog/sun-protection-and-vitamin-d/#:~:text=When%20your%20skin%20is%20exposed,active%20form%20of%20vitamin%20D.  

  2. Kurzbard, Rachel A et al. “Rapid improvement in vitamin D status with dietary 25-hydroxycholecalciferol in vitamin D insufficient dogs.” Journal of nutritional science vol. 10 e12. 22 Feb. 2021, doi:10.1017/jns.2021.4  

  3. Hohenhaus, Ann. “Vitamin D and Pets: What You Need to Know.” Schwarzman Animal Medical Center, 28 July 2021, www.amcny.org/blog/2021/07/28/vitamin-d-and-pets-what-you-need-to-know/.  

  4. “Vitamin D Toxicity in Dogs.” Center for Veterinary Medicine, U.S. Food & Drug Administration. 9 Feb. 2023, www.fda.gov/animal-veterinary/animal-health-literacy/vitamin-d-toxicity-dogs#causes.  

  5. Labbate, Aimee, MRCVS. “Is Vitamin D Poisonous To Dogs?” PocketVethttps://pocket.vet/blog/vitamin-d-toxicity-in-dogs. Accessed 26 June 2023. 

  6. Matlack, Debi. “What happens when your dog eats 60 vitamins D3 5000.” PetCoachwww.petcoach.co/question/?id=102828. Accessed 26 June 2023. 

  7. “Toxicology & Poison Control.” ASPCApro, 21 Mar. 2022, www.aspcapro.org/topics-animal-health/toxicology-poison-control. Accessed 26 June 2023. 

  8. Plumb, Donald C. “Furosemide.” Plumb’s Veterinary Drug Handbook, Distributed by Wiley, Stockholm, WI, 2011, pp. 454–457. 

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