My interest in molluscs was once confined to chowders and pasta dishes. Who knew we’d one day be grinding up marine mussels to produce glucosamine supplements for aging dogs and cats?
Hardly a day passes at our clinic that I don’t talk about or prescribe glucosamine. Increasingly, it is my clients who bring up the subject since a lot of them are taking the stuff for their own arthritis.
Before we get too far on this, here are a few disclaimers. There aren’t many good studies proving glucosamine protects joints. Experts disagree about its value and argue over suggested doses. I have occasionally seen glucosamine cause gastrointestinal issues – a polite form of diarrhea – however, it is generally very safe. According to one highly respected veterinary pharmacologist, “the biggest side effect to giving too much glucosamine is probably a reduction of spending cash” for the pet owner.
I think many of my colleagues would agree that glucosamine seems to help some dogs and cats. So, since it’s safe and often appears to help, glucosamine has become one of the most commonly suggested veterinary supplements. Vets don’t tend to promote a lot of vitamins or other extras. A good diet should provide all the nutrients your pet needs. But glucosamine is not present in adequate amounts in foods, even those that list it as a special ingredient. You have to add extra for any hope of benefit.
We usually recommend a combination of glucosamine and chondroitin. Studies seem to show that glucosamine hydrochloride works better to protect the cartilage in arthritic joints than the sulphate form – see above disclaimers about experts disagreeing and such. Unless a vet has approved the dose, avoid products containing manganese which can be toxic if you give too much.
Glucosamine and chondroitin can be produced from shark cartilage as well as from mussels, raising ethical questions. Stick with a mollusc product or one from domestic animals such as cows. One U.S. study found high levels of lead in some pet joint supplements and questionable quality in others.
Unfortunately, there are few controls over what goes into supplements, particularly for pets. The National Animal Supplement Council was established in the United States to help maintain appropriate standards for such products as glucosamine. To use the NASC seal, manufacturers of pet supplements must meet council guidelines for production processes and labelling information. Membership is voluntary and some very good supplements are produced by companies that do not belong to NASC. Your vet can help recommend good products or assess any you would like to try for an arthritic pet.
There is another supplement aside from glucosamine that can help battle arthritis in our pets. My own clients are probably sick of me extolling the virtues of salmon oil, but it’s a great source of essential fatty acids, known to help combat arthritis, not to mention skin problems, and heart disease. The oil should come from “wild-caught”, not farmed salmon to decrease the risk of it containing toxic contaminants.
Dr. Fiona Gilchrist
Hillcrest Animal Hospital, Trenton – Ontario
October 2012
