In both the human and veterinary pharmaceutical industry, joint supplements are a big business. But are they really necessary? Do they provide therapeutic benefit? Are they harmful? Supplements are not considered drugs and are therefore not regulated by the federal drug administration (FDA). They are dietary supplements, and as such, are not required to go through rigorous testing as is required with drugs. This means that there is no regulatory committee or governing body that ensures potency (what is on the label is in the bottle), disintegration (the product will dissolve in a time considered normal for digestion), and uniformity (each pill, bottle and lot are the same) of the product. So is it worth it?
Glucosamine/chondroitin sulfate is the most common joint supplement discussed for dogs in regards to support for osteoarthritis or degenerative joint disease. In a normal joint, there is a balance between breakdown and production of cartilage. Cartilage is a type of connective tissue that protects bone and provides cushion and lubrication to joints. Cartilage cells are suspended in a matrix of collagen fibers and proteoglycans. Glucosamine and chondroitin sulfate are both part of the proteoglycan molecule and their job is to assist with water uptake so the cartilage stays soft and lubricated. As degenerative changes affect the joint, more and more cartilage is broken down leading to the pain and discomfort associated with osteoarthritis. The ability of cartilage cells to produce their own glucosamine may decrease with age and when there is increased demand as with arthritis. So by providing oral supplementation, the goal is to provide cartilage cells the building blocks necessary to help repair cartilage or at least slow destruction. It has also been suggested that both glucosamine and chondroitin sulfate have anti-inflammatory properties thus providing additional therapeutic benefit.
But do scientific studies actually prove these supplements are beneficial? Although there are numerous studies evaluating the use of supplements in joint disease, the hard scientific evidence of consistent benefit is questionable. This is due to small sample size, difference in product formulation and dosing, subjective and objective assessment of outcome, and length of trials. While some studies show that patients with osteoarthritis using glucosamine/chondroitin supplementation had improvement in clinical function, other studies comparing supplements to non-steroidal anti-inflammatory pain medications (NSAIDs) show either more clinical improvement in dogs with NSAID treatment or improvement in only those treated with an NSAID. In other studies, there is some indication that the use of supplements with NSAIDs together potentiate the inhibition of pro-inflammatory mediators that cause pain associated with arthritis.
So back to the question, is it worth it? Since the majority of glucosamine/chondroitin supplements are well tolerated in dogs with minimal side effects and some studies show clinical benefit, a trial for your pet may not be a bad idea. It certainly warrants a discussion with your veterinarian if you have a dog prone to osteoarthritis or who has early clinical indicators of osteoarthritis. For dogs and cat, in terms of bioavailability, it is best to use veterinary products that are labeled for companion animals. You should also speak with your veterinarian about appropriate dosing and length of treatments. Some companies provide information about potency and uniformity of product that make them more reliable options. Remember your veterinarian is an advocate for your pet. We want your pet to live a happy, comfortable life! Discuss your concerns with your vet and together, we can make a comprehensive treatment plan for your 4 legged companions.