Most people take the supplement glucosamine to ease the discomfort of aching joints. While contention remains over the substance's alleged benefits for your joints, a new study has found glucosamine could have a positive effect of a different sort.
A massive study of nearly half a million medical records suggests those who take this popular supplement appear to have a significantly lower risk of developing coronary heart disease, stroke, and other cardiovascular conditions.
Researchers from Tulane University in New Orleans used data from the UK Biobank to investigate suspicions that glucosamine might have health benefits aside from alleviating the pain of bad knees.
In many countries around the world, including the UK, the US, and Australia, glucosamine is sold over the counter as a food item. That means authorities are confident it won't harm you in small enough doses, but stop short of recommending it as a form of therapy.
Not that this stops retailers from promoting it to consumers as a scientifically-backed treatment for inflammatory conditions, including osteoarthritis.
Glucosamine is an amino sugar that occurs naturally in animals and fungi, forming a part of biochemical 'building' structures such as chitin.
This makes glucosamine a stepping stone to other polysaccharide compounds used in the construction of tissues such as cartilage. Taking this compound is supposed to help promote the repair of the worn articular cartilage in our spines - at least according to marketing claims.
While not an unreasonable thought, the reality is a little ambiguous.
It's true that research generally leans towards showing significant improvements in symptoms of joint degeneration and inflammation, especially if used in conjunction with another supplement called chondroitin sulfate.
But doubts linger over the quality of methodologies, especially among studies run by companies with a potential conflict of interest. The European Union is so far unconvinced of the supplement's benefits, where it's only available on prescription.
Until there's a strong consensus of a clear causal relationship between the supplement and health claims, the case for glucosamine will remain a little murky.
This new study - whose authors have declared they have no conflict of interest - might not cast any deciding votes on the matter when it comes to joint pain, but it does add an interesting new perspective.
The research team analysed just over 466,000 records of individuals who showed no sign of having a cardiovascular disease event. They were then quizzed on their use of supplements such as glucosamine.
Over the next seven years, participants were tracked for signs of heart disease and stroke.
Adjusting for factors such as smoking, body mass index, diet, and age, the researchers found that one in five participants who were regular consumers of glucosamine were less likely to suffer from some kind of cardiovascular condition.
Breaking it down further, they were 9 percent less likely to have a stroke and 18 percent less likely to develop coronary heart disease. They also had 22 percent lower chance of dying from cardiovascular disease.
Taking smoking into account, regularly taking glucosamine dropped risk of cardiovascular disease for current smokers by more than a third.
The research doesn't directly help us unravel the potential mechanisms of supplementary glucosamine's impact on our health. But taken in context with other research, raising levels of glucosamine in the blood could help reduce levels of c-reactive protein, which is associated with inflammation.
As usual, more research could help build a solid case. Given close to 18 million people die from cardiovascular disease every year, evidence that a simple supplement could make a big difference is worth following up on.
In the meantime, glucosamine supplements should still be taken with the figurative grain of salt.
While they're a fairly benign supplement for most of us, there are risks for anybody using it alongside medications such as warfarin. So have a chat to your doctor first before you buy a bottle.
This research was published in The BMJ.