Our pets are living longer, but with those extra years comes a drawback: age-related health problems. Many pet owners try to turn back the clock by giving their furry companions vitamins and supplements. Packaged Facts market research firm estimates that in 2014, pet owners spent about $541 million on supplements or treats with nutritional benefits. Joint deterioration and cognitive dysfunction fueled a large chunk of those sales.

Here are five things you need to know before adding vitamins and supplements to your pet’s diet.

1. Your pet’s kibble may be enough.

"Your average healthy dog or cat on a quality commercial pet food does not require any dietary supplementation," said Dr. Jennifer Monroe, a veterinarian with Eagles Landing Veterinary Hospital in Georgia. "Most commercial pet foods add vitamins and minerals to their diets to provide complete and balanced nutrition for pets."

When in doubt, look for brands labeled “complete and balanced” by the Association of American Feed Control Officials (AAFCO). (And if you want to know more, read this story about what kind of food to feed your dog.) Monroe notes that some pets benefit from vitamins and supplements, particularly any cat or dog that eats home-cooked food, any pet with a metabolic disorder or deficiency, and any pet that has lost its appetite.

"In these pets, multivitamins are absolutely essential and extremely beneficial," she said.

2. Dosage levels matter, so consult your vet.

Excessive amounts of certain vitamins, including vitamin D, can result in illness or even death.

In January 2019, Hill's Pet Nutrition and Science Diet voluntarily recalled 25 varieties of canned dog food because of potentially elevated levels of vitamin D. The company said it first learned of the issue after receiving a complaint about a dog showing signs of high vitamin D levels. They confirmed the problem was from a supplier error.

"While vitamin D is an essential nutrient for dogs, ingestion of elevated levels can lead to potential health issues depending on the level of vitamin D and the length of exposure," the company announced in its press release. "Dogs may exhibit symptoms such as vomiting, loss of appetite, increased thirst, increased urination, excessive drooling, and weight loss. Vitamin D, when consumed at very high levels, can lead to serious health issues in dogs including renal dysfunction. Pet parents with dogs who have consumed any of the products listed and are exhibiting any of these signs should contact their veterinarian. In most cases, complete recovery is expected after discontinuation of feeding."

Your vet can provide dosage information and recommend veterinary formulations made specifically for pets.

3. Supplements aren’t a cure-all.

Monroe warns that supplements will not make up for cheap pet food, which often contains more fat, less protein and too many filler ingredients.

"In my experience, it is better to invest a bit more in the diet you are feeding rather than trying to make up for any deficiencies with supplements," she said.

4. Supplements can soothe a pet’s achy joints.

dog's leg Supplements can be vital for senior dogs that may be suffering from arthritis. (Photo: Chanchai Boonma/Shutterstock)

If your pet hesitates at the foot of the stairwell, arthritis or joint health may be the culprit. Keep glucosamine and chondroitin in the medicine cabinet to help soothe achy knees. Monroe notes that these supplements can provide significant relief to our four-legged companions.

"Pets with joint pain from osteoarthritis can often be maintained on these supplements alone, with reduced dosages of non-steroidal, anti-inflammatory drugs like aspirin or with alternative pain control modalities such as laser therapy," she said.

5. Giving pets vitamins need not be a pain.

My dog Lulu has become quite adept at seeking and discarding any pills slipped into her kibble. Cats are even more persnickety about foreign objects in their food, which has prompted several companies to create flavored treats with hidden health benefits.

"The common denominator for children and pet dogs and pet cats is that they are all very fussy about consuming pills and tablets and dietary supplements," said Guy Setton, vice president of business development for Novipet, a division of Maabarot dietary supplement company. "On the children’s side, we developed a very tasty soft chew around five or six years ago that enabled parents to give their children a very tasty treat, which included an active ingredient of the dietary supplement. Once we saw success with children, we immediately saw that we should duplicate for dog and cats."

Novipet made its U.S. debut in 2010 with a line of soft chews sold in blister packs. Chamomile extract, L-taurine and L-tryptophan address anxiety, while glucosamine and chondroitin sulfates tackle canine joint health. Fish-shaped soft chews made with vitamin E, petrolatum and brewers dried yeast provide cats relief from hairballs. A feline multivitamin and omega-3 version also are available. Not surprisingly, a probiotic digestive aid is on the way for pooches with sensitive tummies.

While the occasional vitamin or supplement can help, exercise and high-quality pet food are the best tools to ensure a long and happy life. If you decide to give your pets supplements or any treats, be sure to check the calorie count and adjust food levels accordingly.

"If [pet owners] wonder if there is a supplement out there that may be beneficial for their pet, just ask your vet," Monroe said. "Just because a product is available over the counter, and is listed as a nutritional supplement, doesn't mean that it is efficacious or safe. However, used safely and appropriately, supplements can be a wonderful thing."

Editor's note: This article has been updated since it was originally published in April 2013.

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