Dog Vitamins and Supplements: Get the Facts

WebMD teams up with veterinarians to talk about vitamin safety, dangers, and what to look for.

By Elizabeth Lee
WebMD Pet Health Feature

Reviewed by Elizabeth A. Martinez, DVM

Many dog owners take dietary supplements or vitamins to improve their health. And increasingly, they're likely to give them to their pets, too.

As many as a third of dogs and cats in the United States may receive vitamins or supplements. The most common are multivitamins, supplements to support arthritic joints, and fatty acids to reduce shedding and improve a coat's shine, according to a 2006 study published in the Journal of the American Veterinary Medical Association. Pet owners also may give probiotics to alleviate gastrointestinal problems or antioxidants to counteract the effects of aging, such as cognitive dysfunction.

With a growing population of aging, overweight dogs, the market for dog supplements is expected to increase 37% by 2012, reaching $1.7 billion, according to Packaged Facts, a market research firm.

Veterinary nutritionist Susan Wynn, DVM, sees many clients in her practice near Atlanta who give their dogs vitamins and nutritional supplements. “They come in with bags full sometimes,” she says.

But do dogs need those vitamins and supplements? And are they even safe? Experts say some work, others don't, and some aren't necessary and may even be harmful to dogs.

“Most people are doing it because they want to, not because it's necessary,” says C.A. Tony Buffington, DVM, PhD, professor of veterinary clinical sciences at The Ohio State University Veterinary Teaching Hospital.

WebMD talked with the experts to get answers to some frequently asked questions about dog vitamins and supplements.

1. Does my dog need vitamins?

Most dogs receive a complete and balanced diet - including necessary vitamins and minerals - from commercially processed dog food, according to the U.S. Food and Drug Administration. Dogs fed a homemade diet may need supplements. “It's absolutely critical, but it should be done to match the diet,” Wynn says. “You can't just create a meal and give your dog a vitamin.” Check with a veterinarian or nutritionist for help in determining what, if anything, is needed.

2. Is there any danger in giving my dog vitamins?

Possibly. If an animal already eats a balanced diet and receives excess portions of some vitamins and minerals, they could be harmful, according to the FDA and veterinarians.

Too much calcium can cause skeletal problems, especially in large-breed puppies; too much vitamin A can harm blood vessels and cause dehydration and joint pain. Excess vitamin D can prompt a dog to stop eating, harm bones, and cause muscles to atrophy.

3. Should I check with my vet before supplementing?

Absolutely, vets say. Symptoms that look like arthritis, such as a dog with a weak rear end, could instead be a neurological problem. A poor coat could indicate skin, metabolic or hormonal problems.

“Don't forego traditional therapies, especially if it's a life- or organ-threatening illness for your pet,” says Dawn M. Boothe, DVM, MS, PhD, director of the clinical pharmacology lab at the Auburn University College of Veterinary Medicine. “Make sure you stick with a standard of care and use the supplements as they were intended, as supplements.”

Ingredients in some supplements, such as herbals, may interact with other medicine an animal is taking. Your vet can also assess whether your pet needs a supplement.

“If they're eating a complete and balanced diet and they're healthy and have no problems, they don't actually need supplementation,” Wynn says. She recommends fruits and vegetables to pet owners who want to give extra nutrients. Other than that, she limits her recommendations if a dog is healthy.

“We want to use things that are safe long-term,” Wynn says. “Probiotics fit that bill. That's probably all I would recommend.”