Pet supplements skimp

Arthritis supplements bought by millions of pet owners for their dogs, cats and horses sometimes skimp on the ingredients the makers claim can help aching paws and aging joints, and some contain high amounts of lead, an independent lab found.

Four of the six joint supplements for animals tested by ConsumerLab.com lacked the amounts of glucosamine or chondroitin promised on their labels or had other flaws, such as lead. Wider testing by a trade group of 87 brands found that one-quarter fell short.

Over-the-counter dietary supplements for humans do not have to be proven safe or effective before they are sold, and pills for pets get even less scrutiny.

"There is and there always has been" a quality problem, although many companies do a good job, said Mark Blumenthal of the American Botanical Council, which tracks research on herbal products.

Even when these supplements contain what they claim, there is little evidence that they work, veterinary experts say. A large government study of people with arthritis found that glucosamine and chondroitin did no better than dummy pills in easing mild pain. Testing these supplements on pets is harder.

"You can't ask a dog or a cat to give you a subjective impression of how they're feeling after taking the product for several days. They can't say, 'On a scale of 1 to 5, I feel better or worse,' " Blumenthal said.

Up to one-third of dogs and cats in the U.S. are given supplements, a government report estimates. Sales of pet supplements have roughly doubled since 2003, to nearly $1 billion a year in the United States, according to the Nutrition Business Journal. These supplements are sold over the Internet and at pet supply stores and some groceries.

In 2007, the FDA asked an expert panel to look into three popular pet supplements - lutein, evening primrose oil, and garlic - but the group could not agree on a safe upper limit.

"Many people presume that supplements are safer than drugs, but the reality is that there is very limited safety data on dietary supplements for horses, dogs, and cats," the panel concluded.

The National Animal Supplement Council, a trade group in suburban San Diego, found that 28 percent of the 87 brands it tested in April did not contain what was claimed, said council president William Bookout.

He warns consumers not to expect too much from a pill: "There isn't any magic bullet out there. It is not hip replacement in a bottle."

Babette Gladstein, a veterinarian who makes house calls for dogs and cats in New York City, said she uses alternative methods but not supplements, because there is not enough proof they work. For overweight pets with bad knees, she advises healthy diets and weight loss.

"I teach the clients how to massage their animal, how to stretch their animal, how to get better range of motion," Gladstein said.