STUDY: Make sure you are getting your antioxidants

JOURNAL: J Clin Invest 2003;112:915-923.

AUTHORS: Dr. Timothy J. Chambers

ABSTRACT: Although the link between estrogen deficiency and bone loss is well established, the mechanisms involved are unclear. Now, new study findings indicate that the association is mediated by thiol antioxidants in osteoclasts.

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COMMENTARY: In other body regions, estrogen has been shown to suppress reactive oxygen species (ROS), which are known to stimulate osteoclasts. Therefore, it is possible that estrogen deficiency promotes bones loss by facilitating ROS stimulation of osteoclasts. Specifically, antioxidant levels may be low when estrogen is lacking.

In vitro analysis revealed that estradiol increased antioxidant levels in osteoclast-like cells. Treatment with a glutathione stimulator prevented osteoclast formation, whereas treatment with a glutathione inhibitor had the opposite effect. Treatment with estradiol as well as the glutathione stimulator suppressed expression of TNF-alpha, a cytokine strongly linked to estrogen-deficiency bone loss.

"These results have important implications for bone biology and the treatment of osteoporosis", the researchers state. Although further studies are needed to determine the exact mechanism of bone loss, "our results predict that osteoporosis should be prevented by therapies that increase oxidant defenses in bone," they add.