More Evidence Glucosamine and Chondroitin Work: What the Heck is Quercetin?
Can quercetin help arthritis? More research has just been published showing that a combination of glucosamine, chondroitin, and quercetin glycosides work to help osteoarthritis pain. The small randomized controlled trial tested 40 Japanese patients with knee arthritis, half of which got the supplements and half a placebo. The supplement group not only had better knee function, but also better biomarkers showing less cartilage breakdown. I’ve blogged before on biomarker and MRI studies showing that glucosamine and chondroitin seem to work well for most arthritis patients. However, what the heck is a “quercetin glycoside” (QG)? QG is a dietary supplement in the flavonoid class found in many foods including black and green tea, apples, red onions, grapes, green leafy vegetables, and berries to name a few. Several properties have been suggested for QGs including anti-viral, glucose stabilization, anti-cancer, and anti-inflammation. As far as it’s effects on cartilage are concerned, several studies have been published. One animal study found that it and other flavones helped to stabilize cartilage breakdown by suppressing the cartilage breakdown pathways. Another study testing cartilage in the lab found the QGs and Curcumin helped to reduce loss of aggregan (a chemical that gives cartilage it’s bounce). I was only able to find one other human study in arthritis, but in that study the same combination (glucosamine-chondroitin-quercetin) helped reduce pain and increase function in osteoarthritis patients but not rheumatoid arthritis patients. The supplements seemed to work by improving the properties of the synovial fluid in the knee. Synovial fluid is the natural “lubricant” found in our joints that helps protect and provide nutrients for normal cartilage, so improving it makes sense as a mechanism to help arthritis (this is likely how SynVisc shots work). The upshot? IMHO, the data on glucosamine and chondroitin is solid enough that these important dietary supplements should be taken by every arthritis patient. While Quercetin has a strange name, the emerging data on combining QGs with glucosamine and chondoitin looks very promising.