The chemical structure of isoflavones is very similar to that of estrogen.

Researchers at the University of Barcelona, in Spain reviewed the evidence.

First, the details.

  • 737 studies dealing with isoflavones and bone were identified.
  • Of these, 36 were considered worth including in the review.

And, the results.

  • From laboratory and animal studies…
    • Isoflavones appear to stimulate bone formation (osteoblastic) and inhibit the breakdown of bone (osteoclastic).
  • Peri- and postmenopausal women…
    • There’s evidence of a beneficial effect of isoflavones on bone health when high-isoflavone soy protein is incorporated in the diet.
  • Inconsistencies in study results are related to differences in study design, the variety of soy sources of isoflavones, time of analysis, and the variability in the bioavailability and metabolism of isoflavones.

The bottom line?

The authors concluded, “Most of the studies suggested a positive relationship between isoflavones and bone health.”

They also believe that better designed studies are needed.

Any benefits must be balanced by the potential risk associated with soy isoflavones, as reviewed here.

11/22/10 20:21 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.