Vitamin A Toxicity in Dogs

Vitamin A toxicity in dogs most often occurs accidentally or inadvertently. It has potentially serious side effects for your pet, including bone damage and even death. Let’s find out how vitamin A helps your dog, what a case of vitamin A toxicity looks like and what steps should be taken to resolve the problem in your dog.

How Vitamin A Benefits Your Dog

Vitamin A is a fat-soluble antioxidant vitamin that is stored primarily in the liver until your dog’s body needs it. Fat-soluble vitamins can be stored by your dog’s body (unlike high levels of water-soluble vitamins, which are eliminated from your dog’s body by his excretory system), which makes them more likely to build up to toxic levels in your dog.

Vitamin A helps your dog’s:

  • coat
  • muscles
  • nerves
  • skin
  • vision

It also helps female dogs maintain ovarian health and reproduce successfully, and it helps puppies grow and develop normally.

Dietary sources of vitamin A, also called carotene, can include:

  • dairy products
  • dark orange fruits and vegetables
  • egg yolks
  • fish liver oil
  • leafy green vegetables 
  • liver

Please note that the darker the vegetable or fruit color, the higher the carotene level contained in the food.

Safe and Toxic Vitamin A Dosages for Dogs

The American Association of Feed Control Officials (AAFCO) regulates the vitamin levels in all pet food. The group has determined that the recommended minimum daily dose of vitamin A for dogs is 2,272 International Units (IU) per pound of food or 50 IU per pound of body weight.

The toxic dose of vitamin A for dogs has been set at between 2,500 and 113,600 IU per pound of food, but only if this elevated level of vitamin A is fed to a dog daily for months or even years.

Symptoms of Vitamin A Toxicity

Vitamin A toxicity can occur when a dog ingests too much vitamin A. Sometimes this occurs accidentally, as when a puppy consumes a bottle of vitamin A supplements, but in other cases, it occurs inadvertently when an owner gives a dog too much vitamin A. These cases include overuse of fish liver oil supplements or overfeeding of liver.

Symptoms of canine vitamin A toxicity include:

  • appetite loss
  • bone spurs
  • constipation
  • lethargy
  • limping
  • stiffness
  • weakness
  • weight loss

Your dog may also be more sensitive to touch around his front legs and neck.

How to Treat a Vitamin A Overdose

Your veterinarian will diagnose vitamin A toxicity in your pet using diagnostic tests, x-rays and an evaluation of your dog’s medical history. Significant bone remodeling may be evident on your dog’s x-rays, and other diagnostic tests can help your veterinarian determine if long-term organ damage is present from the high levels of vitamin A.

Treatment can include the use of activated charcoal or vomiting if your dog has ingested a large amount of vitamin A supplements at one time. Your dog’s diet may also need to be changed if he has been regularly consuming large amounts of liver to prevent further occurrences of vitamin A toxicity.