One of the questions we often get asked in clinic is just how effective are chondroitin and glucosamine for the symptomatic relief of osteoarthritis?
So, I think it’s timely that we have a quick look at some of the evidence to see what current opinion suggests.
After all, in 2014 the world bought over 29,000 tons of it. If you are already taking it as a supplement, and you feel it helps you, my advice is carry on and this short article is not aimed at persuading you otherwise.
Glucosamine For Joints
Glucosamine especially is a hot topic because of all the supplements on the shelves in health stores the most popular (by a long way!) are those which apparently help our joints.
This is even though sometimes their use is controversial and not even necessarily well supported by research.
What Does Glucosamine Do?
The first question is, what is the role in of glucosamine in the human body? It is well known that glucosamine in the human body is a fundamental building block for both cartilage and tendons.
Specifically, it is a natural constituent of some glycosaminoglycans (e.g. hyaluronic acid and keratin sulphate) found in articular cartilage, intervertebral discs and synovial fluid.
How is Glucosamine Made?
Glucosamine, as a supplement, is harvested from various sources. It also happens to be one of the building blocks of chitin – the material that makes up the shells of crustaceans and shellfish – they are therefore (unfortunately for them) a convenient source for industry (vegetarian options come from mushrooms or processed grains).
It can also be made in the laboratory. However, in this case, it can come in several chemical forms, but the one most used in arthritis is glucosamine sulphate. So, what of the clinical evidence once manufactured?
The premise is of course that if you take it as a supplement it helps reconstruct target structures and I certainly feel that this simple fact alone obviously resonates with people. But is this what happens in reality?
Glucosamine Studies
Studies have shown that glucosamine is easily absorbed, but the current recommended treatment doses (e.g. 1,500 mg/day) barely reach the required therapeutic concentration in plasma and tissue. The symptomatic effect of glucosamine also appears to vary greatly depending on the formulation used and the quality of clinical trials.
The controversy is such that it is not recommended in the most recent National Institute for Health and Care Excellence (NICE) guidelines in 2014. NICE also suggest that much of the evidence surrounding glucosamine is industry sponsored. Commercially funded trials of products are a well-known issue in medicine, and in the case of glucosamine studies it seems that those that are commercially funded turn out to be more likely to show a positive result than those done independently.
Other independent evidence is certainly at best very mixed. Successive studies year on year appear to contradict each other with most authors now agreeing that the case for its efficacy is unproven.
One of the gold standard reviews is a Cochrane review. Cochrane is a global independent network of researchers, professionals, patients, carers and people interested in health. A Cochrane review in 2005, updated in 2007, suggested that whilst glucosamine appeared superior to placebo for treatment of pain and functional impairment from symptomatic osteoarthritis in around 2,500 patients, the benefit at three months was less than that measured at six weeks.
A 2009 systematic review looked at five systematic reviews and one clinical guideline. It concluded that there was evidence for clinical impact but that more research was needed and that as none of the trial data came from the UK, caution should be exercised in applying it here.
A 2012 review concluded that evidence was at best mixed and that any symptomatic effect observed varied greatly with the preparation used and the quality of the trial.
A 2013 study used an Australian formulation of Chondroitin sulphate (800 mg) along with glucosamine (1,500 mg). The combination didn’t relieve pain better than placebo, but it reduced joint space narrowing.
