Reviewing the benefits of soy isoflavone on bone in menopausal women

Researchers from the University of Yamanashi in Japan reviewed studies of soy isoflavones (ie, phytoestrogens [plant estrogens] found chiefly in soybeans) and report “It decreases bone loss in the spine.”

But…

Here’s what they did.

• The results from 10 studies with a total of 608 people were re-evaluated (meta-analysis).

Here’s what they found

• Bone mineral density in the spine among those who consumed isoflavones for 6 months increased significantly compared to those who did not consume isoflavones.
• These favorable effects become more significant when more than 90 mg/day of isoflavones are consumed for 6 months.

The bottom line?
The same researchers published a similar review of 9 studies with a total of 432 people and found a significant inhibition of bone resorption and stimulation of bone formation among women taking less than 90 mg/day for less than 12 weeks.

OK, but we still need to see changes in the rate of fracture among women who eat soy isoflavones. And the available research shows there’s no evidence that soy isoflavones protect against bone fracture.

Today, phytoestrogens should be used in selected women only — those with mild to moderate hot flashes and palpitations during early natural postmenopause.

There is also no evidence that they protect from breast cancer or cardiovascular disease.

12/9/07 15:00 JR