Is a multi-vitamin necessary to give my dog every day?
This is something you really need to discuss with your veterinarian because whether it’s necessary to give your dog one every day will depend upon such things as her age and activity level. Another factor to consider is whether or not your dog has an illness or a predisposition to a particular one.
The big concern for you is that you don’t overdose the dog. Vitamins are broken up into two categories: fat soluble and water soluble. The fat soluble vitamins are A, D, E and K. What that means is that they just keep building up, and they get stored in the dog’s body, creating toxicity.
You need to be especially careful about A and D. For one thing, a dog’s body naturally produces vitamin A so it’s not necessary to supplement. A vitamin A overdose can affect the nervous system and the heart.
Excessive vitamin D supplementation can create an imbalance of the calcium/phosphorous ratio; vitamin D increases calcium absorption. Bone integrity depends on maintaining a proper calcium/phosphorous ratio. Increased calcium can also lead to zinc deficiency. A toxic dose of Vitamin D is 2272 IU per pound of consumed dry dog food.
While vitamin E is important as a natural antioxidant, formation of red blood cells and some of the body’s system, too much can interfere with the absorption of other vitamins—namely, K, which functions for blood clotting. Always be careful of some vitamin E supplements, because they sometimes also contain vitamin A.
Vitamin K has to do with blood coagulation so, while a deficiency can create prolonged bleeding, too much can create swelling and sometimes fever. Best to have only a veterinarian administer this.
The other vitamins are water soluble and, therefore, easily excreted. While there’s no danger, you should also know that the dog’s body produces vitamin C, so it’s not necessary to supplement with this.