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.
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 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."