Black and white women benefit differently from soy

Several important differences between the groups were found at the end of the trial:

• Abdominal fat, sometimes called "belly fat," decreased by 7.5% in the women taking the soy shake, but increased by 8.8% in women taking the dairy shake. This type of fat is closely associated with cardiovascular disease.
• Visceral fat, which is distributed on the organs and is the most dangerous type of fat, decreased by 2.5% in the soy group and increased by 5.3% in the dairy group, however, this difference was not statistically significant.
• The researchers found that, when taking race into account, only the white women lost abdominal and visceral fat; African American women taking the soy shake did not experience improvement in body fat distribution.
• African American women on the soy shake lost weight while white women did not.
• Small changes in blood markers in the women using the soy shake suggested that they may have had slight improvements in blood sugar metabolism and generalized inflammation.

"Soy supplementation reduced abdominal fat in obese postmenopausal women," the study's authors said of their findings.

Reaping soy's rewards

In addition to weight loss or better body fat distribution, women who eat soy may see other health improvements:

• Reduced menopausal symptoms. Women from societies where soy is eaten regularly are less likely to suffer from hot flashes, and several studies have found that adding soy to a Western diet can decrease symptoms such as hot flashes and vaginal dryness.
• Lower blood pressure. Soy protein has been found to lower blood pressure in both men and women.
• Lower cholesterol levels. Eating soy foods such as tofu, tempeh, miso, and soy nuts can reduce total and LDL-cholesterol levels.
• Stronger bones. Some, but not all, studies have found that soy foods and supplements can preserve bone density in postmenopausal women.

(Am J Obstet Gynecol 2010;203:153.e1-9)