Vitamin D Deficiency in Dogs
Known as the “sunshine vitamin” because exposure to sunlight helps the body produce it naturally, vitamin D is an essential vitamin for dogs, which means the dog’s own body does not produce a sufficient amount and therefore vitamin D must be included in the animal’s diet for the dog to maintain optimal health.
Vitamin D plays an indirect role in bone growth and maintenance by managing levels of calcium in the body. It controls absorption of calcium from the intestine, the movement of calcium in and out of bone, and the amount of calcium excreted by the kidneys. Muscles and nerves also require vitamin D for proper functioning. Insufficient vitamin D levels can lead to congestive heart failure in dogs, as well as an increased risk for complications due to heart disease and bone disorders such as osteomalacia (softening of bones) and rickets (bone deformities). Research has also shown that low levels of vitamin D are linked to an increased risk of cancer.
The most common food sources of vitamin D for dogs are liver, fish and egg yolks, but it can be found in beef and dairy as well. The Association of American Feed Control Officials (AAFCO) recommends adult dog food provide a minimum of 500 international units (IU) of vitamin D per kilogram of food, and no more than 3,000 IU per kilogram of food. However, this applies only to commercial pet foods. If you are feeding a home-prepared diet it is important to speak to a veterinarian with board certification in veterinary nutrition to ensure your dog is getting all the nutrients needed for optimal health. If you are concerned your dog isn’t getting sufficient vitamin D through diet alone, a multivitamin supplement formulated for dogs is a great way to help provide nutrients in appropriately balanced levels.
It is important to note that vitamin D is a fat-soluble vitamin, which means excess amounts are not excreted by the body as water-soluble vitamins are, but are instead stored in the liver, fatty tissue and skeletal muscle. This inability to excrete extra vitamin D can lead to toxicity if given in large amounts. While dogs can overdose on vitamin D, the most common causes are when dogs ingest prescription medications or rodenticides.
Vitamin D Studies