Evidence of use of glucosamine, chondroitin, methy-sulfonylmethane (MSM) and green lipped mussel for osteoarthritis in dogs and cats

Dr Hilary Lam BVSc, PgCert, MVS. Happy Valley Veterinary Clinic

Nutraceuticals in human and veterinary medicine often fall into a grey zone of regulation and yet its has developed into a billion dollar industry over the decades. In the early 1990s there has been an increasing attention of using dietary supplements for our furry friends with osteoarthritis (OA). Their efficacy has been widely advertised on television, newspapers and the internet. Let's have a deeper understanding of evidence based medicine (EBM) behind these nutraceuticals.

Different regulatory bodies use different systems to rank the strength of evidence of scientific studies. Evidence-based ranking system used by Food and Drug Administration's (FDA) aims to provide the reader with a sense of reliability of the data presented to them and how comfortable they can be with the results. The system categorizes study results into 4 levels: 1) High, 2) Moderate, 3) Low level, 4) Extremely low level of comfort. 'High level of comfort' means that qualified researchers agree that specific claim is scientifically valid, while the latter ones usually have a relatively lower consistency which are based on relatively low quality studies.

Evidence based behind glucosamine, chondroitin, MSM, green lipped mussels in OA dogs

There are numerous nutraceutical preparations available over the counter containing glucosamine, chondroitin and methyl-sulfonylmethane (MSM) and green lipped mussel for joint supplementation in dogs. Main rationale behind their use is aim for synthesis of articular cartilage, which may help to repair or slow down the damage of cartilage. There are anecdotal evidence and tissue culture to support their an anti-inflammatory and analgesic effect.  Two scientifically valid trials examined the use of glucosamine hydrochloride, chrondroitin as major components for improving clinical signs for OA in dogs. Interestingly, one study subjectively showed a positive effect, while the second one showed no significant effect. In clinical situation, confusion arises in which study one should use to help make decision whether to use the products. Overall we can concluded that the use of glucosamine, chondrontin in OA dogs is of “low to moderate level of comfort".

On the other hand, there were three trials performed to evaluate the use of green lipped mussels in OA dogs. All trials subjectively showed a positive effect with some uncertainties existed. In general, we believe that green-lipped muscle has a "moderate level of comfort “that it will show positive effects on OA dogs.

Evidence base behind glucosamine , chondroitin, MSM, green lipped mussels in OA cats

In 2014, total 30 with painful cats with OA underwent a study, Group 1 (17 cats) receiving meloxicam and Group 2 (13 cats) receiving glucosamine and chondroitin supplement for 70 days were compared. Although meloxicam showed marked improvement on initial stage. When placebo was used in the second part of the trial, results showed that glucosamine/ chondroitin group was found to have longer lasting effect compared to the meloxicam group. Based on the above reference, glucosamine, chondroitin supplement in cats with OA has “moderate level of comfort”. MSM and Green lipped mussel extract is also popular however its mode of action in cats is uncertain, more evidence based studies is required to prove its clinical application in cats.

Side effects of glucosamine

Side effects of glucosamine in dogs and cats are rare which may include gastrointestinal upset as the most commonly reported sign.  The proof of diabetes mellitus may be precipitated after use of glucosamine has not been substantiated. 

In conclusion, there have been discrepancy between the claim of nutraceuticals for joint health on media and the data presented based on EBM medicine. Overall these nutraceuticals have certain role in multimodal approach in management of OA in small animals and it is important for us to develop a scientific understanding of these nutraceuticals so that we can provide the best recommendation for our furry friends.

Evidence based medicine- integrating individual clinical expertise with the best available external clinical evidence from systematic research.

Anecdotal - knowledge based on isolated observations and not yet verified by controlled scientific studies.

References:

Budsberg, SC. Pacific Veterinary Conference 2015. "Evidence of Use of Nutraceuticals in osteoarthiritis 'Joint Juice' Insane Quackery or is the Internet Right?"

S Little. August's Consultations in Feline Internal Medicine, Volume 7, 1st Edition. Saunders, 2015, pp 965.