Glucosamine sulfate (GS), chondroitin sulfate (CS), and methylsulfonylmethane (MSN) are just a few of many non-drug interventions that are in common usage for the pain and functional loss of osteoarthritis. Evidence for efficacy of GS and CS is present in the scientific literature (1-3) although some still doubt their value (4;5). While the safety of GS has been clearly demonstrated in numerous trials (6), concerns have been raised as to the purity and accuracy of labeling in CS products (7). ConsumerLab.com, an internet based nutritional testing company, found 4 of 21 tested brands of CS contaminated with lead and 4 were mislabeled or failed to disintegrate properly (8).
Avocado soybean unsaponifiables (ASU) is a largely ignored supplement in the popular media and in doctor’s offices. In spite of a lack of recognition it has possibly the highest level of evidence supporting its effectiveness of all the herbal or nutritional supplements. The Cochrane Collaboration reported in 2001 “evidence for avocado-soybean unsaponifiables in the treatment of osteoarthritis is convincing” (9). A second review published in 2006 came to a similar conclusion, rating the evidence as “good” (10). Blotman et al reported in their three month randomized controlled trial (RCT) of 163 subjects that ASU reduced the need for NSAIDs and improved function compared to the placebo (11). Another RCT found NSAID use was reduced by more than 50% in 71% of patients receiving ASU (12). Lastly Maheu et al reported a 20.9 point drop in the visual analog pain scale in their RCT of 164 subjects when using ASU (13).
In addition to positive effects on pain and function, preliminary studies demonstrate positive structure modifying effects as well. Henrotin et al reported ASU “may promote OA cartilage repair by acting on subchondral bone osteoblasts” (14). A second study found ASU “significantly reduced the progression of joint space loss” (15).
Maximum treatment effect requires 2 months of use (13) and 300 mg daily has been shown to be as effective as 600mg daily (12).
In conclusion ASU appears to be an overlooked yet efficacious and cost-effective option for functional loss and pain of osteoarthritis, particularly in the hips and knees.