I'm surprised at how often I hear orthopaedic consultants recommend the use of glucosamine to help improve or even prevent osteo-arthritic symptoms of pain and stiffness. In fact, specialists in joint disorders are far more likely to recommend it than GP's or family practitioners.
So I thought I'd just summarize the current state of thinking about the use of this nutritional supplement, and address a few possible grey areas and mistaken assumptions that often crop up.
What is it for?
All bones, where they meet with another bone to form a joint, have a smooth layer of glistening blue-white cartilage literally 'capping' the bone. The other parts of the bone do not have this cap of cartilage. The idea is that this smooth cartilage layer can 'mate' or rub against the same layer on the other bone, and thus the joint of the two bones can move in a slippery smooth way. This could not happen if bare bone was rubbing against bare bone. When this 'articular' cartilage is damaged (either through trauma, or through ageing wear-and-tear) then symptoms of pain and stiffness can develop. This is called osteo-arthrosis. Note: don't confuse this kind of cartilage damage with damage to the other types of cartilage found in intervertebral discs of the spine or the menisci of the knee - that's a different kind altogether, and cannot be helped by glucosamine.
How does it work?
Glucosamine is a natural substance which forms part of the building block of articular cartilage. To quote Wikipedia: "Since glucosamine is a precursor for glycosaminoglycans, and glycosaminoglycans are a major component of joint cartilage, supplemental glucosamine may help to rebuild cartilage and treat arthritis."
Where does it come from?
The most common source is the skeletons of crustaceans. For vegetarians, or even people who may be allergic to shell-fish, this may be a problem. In this case it is possible to get glucosamine sourced from fermented corn (for example). This will be more expensive and harder to locate than the readily available gluscosamine from shell-fish skeletons.
What's this 'glucose' stuff? Will it cause a problem with my diabetes, or make me put on weight?
No! The fact that it is called glucosamine is just to describe the fact that this compund is chemically a combination of a sugar AND a protein molecule. It is NOT sugar. However, it is fair to say that current thinking is not clear about the potential effects of this supplement on diabetes - check with your doctor before using it if you are diabetic.
What's this business about sulphate and hydrochloride?
The glucosamine - which is the so called active ingredient - needs something to latch onto to be transported around the body for absorption and final processing. It is very commonly bound with sulphate. Most research has been done on this combination, and it is believed that glucosamine sulphate is effectively absorbed by the digestive system. Less research has been done on glucosamine hydrochloride, and indeed some people are of the opinion that glucosamine hydrochloride is less easily absorbed by the digestive system. My advice: stick with glucosamine sulphate.
Is it expensive?
No, these days it's fairly cheap.
What about chondroitin sulphate and where does it come from?
This is another form of naturally occurring substance found in articular cartilage. Indeed, the most common source of it is the windpipes of cows and pigs! If this puts you off, then you might need to try and find products whose source is - for example - shark's cartilage.
Do they work?
Certainly, the evidence indicates that glucosamine sulphate can reduce feelings of pain and stiffness. It may also help thicken the cartilage layer, though the the evidence for this is weaker. As far as chondroitin sulphate is concerned, the evidence for this is less developed. However, some research showed that chondroitin may be useful when swelling of the joint is a more prominent symptom.
How long do I need to take it for?
A couple of months at least ... then stop, and see if your symptoms change. You will know if it works or not.
Is there anything I can take it with that also helps?
I'm a great fan of fish oil. Fish oil - so called omega 3's - has a lot of beneficial effects, but as far as joints are concerned one of fish oil's effects may be to reduce the degree of inflammation that results following any injury to the tissues of the joint. Contained within these inflammatory products are enzymes that sometimes further degrade articular cartilage. So fish oils may help cartilage by preventing inflammation, and glucosamine may help by preventing the damage to the cartilage that causes the inflammation. Both these products may thus beneficially help both aspects of this all too common 'vicious circle', and therefore they work together 'synergistically'.
Does it matter which brand I buy?
In one sense no - glucosamine is just glucosamine. The problem is you don't know if what you are getting is glucosamine. One study (I heard this second hand from a surgeon, so I don't have the references for this) indicated that out of circa 27 different brands of glucosamine sulphate, up to a half had reduced amounts of or even none of the active ingredient! I would recommend buying from well-known brands who have a reputation to protect.
Since I added the above entry on glucosamine sulphate, there has been more discussion on whether it can actually interfere with sugar metabolism and thus potentially cause a problem for patients with diabetes.
It is fair to say that there is no conclusive evidence that it can, but in the light of this ambiguity it is probably best for people with diabetes mellitus type 1 or 2, and especially those taking medication such as metformin or insulin, to consult with their GP or specialist before using glucosamine sulphate for their joints.
The following is a good summary of the current issues and is worth reading ...
As far as I'm aware, a recent 'study of studies' concluded that the evidence for a significant beneficial effect is not as strong as we all might have thought ...