Soy Foods May Build Better Bones in Early Menopause: True or False?
A diet rich in soy with isoflavones may provide beneficial effects on bone health in older women, according to results of a recent study presented in the United Kingdom, which is exciting news giving additional options to reduce the risk of osteopenia and osteoporosis. So—what are isoflavones and how can they possibly benefit women in early menopause?
Isoflavones are a class of phytoestrogens—plant-derived compounds with estrogenic and antioxidant activity. The term “estrogenic” means the compounds have estrogen (female hormone) characteristics. Foods that have antioxidant qualities may help reduce certain types of cell damage. Legumes, such as soybeans, and soy products (eg, tofu) are the main dietary sources of isoflavones.
Isoflavones, Menopause and Bone
To determine the effect of soy isoflavones on bone during early menopause, Thozhukat Sathyapalan, MD, and his colleagues from the United Kingdom, Italy and Qatar, studied 200 women within 2 years after the onset of their menopause. They gave the women 30 grams of soy protein with or without 66 milligrams of isoflavone each day for 6 months.
The investigators looked at changes in two markers, or indicators, of plasma bone turnover—bCTX, which indicates bone resorption or breakdown, and P1NP, which indicates bone formation. They also evaluated the patients for changes in cardiovascular risk (eg, heart disease) and thyroid function.
- The investigators noted that levels of bCTX were significantly lower among the patients given soy with isoflavones. This indicated patients had less breakdown of bone than patients given soy alone.
- For the other marker, P1NP, there were no significant differences overall.
- However, during the study, when the investigators looked at the difference between the measurements at 3-months and 6-months, there was a significant reduction of P1NP concentrations among those patients given soy with isoflavones.
- The patients taking soy with isoflavones also had improvements in cardiovascular risk markers, including fasting glucose (blood sugar), fasting insulin, and C-reactive protein.
The investigators concluded that soy with isoflavones “may confer a beneficial effect on bone health,” and noted that the mechanisms of benefit parallel those of antiresorptive agents used to treat postmenopausal osteoporosis, such as bisphosphonates, calcitonin, and denosumab.
In an interview with the British online newspaper, The Telegraph, Dr. Sathyapalan, from the University of Hull, in England, said: "We found that soy protein and isoflavones are a safe and effective option for improving bone health in women during early menopause.” He noted that the 66 mg of isoflavone used in the study “is equivalent to eating an oriental diet, which is rich in soy foods. In contrast, we only get around 2 to 16 mg of isoflavone with the average Western diet." He added, “supplementing our food with isoflavones could lead to a significant decrease in the number of women being diagnosed with osteoporosis."