Dietary Soy Isoflavones and Bone Mineral Density: Results from the Study of Women's Health Across the Nation

Abstract

Isoflavones are naturally occurring selective estrogen receptor modulators, with potential bone protective effects. To study the relation between soy isoflavone intake and bone mineral density (BMD), the authors analyzed baseline data from the Study of Women's Health Across the Nation, a US community-based cohort study of women aged 42-52 years. Their 1996-1997 analysis included African-American (n = 497), Caucasian (n = 1,003), Chinese (n = 200), and Japanese (n = 227) participants. Genistein and daidzein intakes were highly correlated (r = 0.98); therefore, analyses were conducted by using genistein. Median intakes of genistein (measured in micrograms/day) by African Americans and Caucasians were too low to pursue relational analyses further. For Chinese and Japanese women, median genistein intakes were 3,511 and 7,151 microg/day, respectively. Ethnic-specific, linear models were used to predict BMD as a function of energy-adjusted tertile of intake, controlled for relevant covariates. For Chinese women, no association between genistein and BMD was found. Premenopausal, but not perimenopausal, Japanese women whose intakes were greater had higher spine and femoral neck BMD. Adjusted mean spinal BMD of those in the highest tertile of intake was 7.7% greater than that of women in the lowest tertile (p = 0.02); femoral neck BMD was 12% greater in the highest versus the lowest tertile (p < 0.0001).

Effects of Dietary Genistein on Nutrient Use and Mineral Status in Heat-Stressed Quails

“…This result is in agreement with the results of previous studies on genistein in rats [6,39]. It has been documented that soy isoflavones can increase bone mineral content and bone density in humans [15,17]. Genistein has been shown to increase proliferation and differentiation of osteoblast-like cells and collagen synthesis [9] and decrease intracellular Ca concentrations in osteoclasts in animals [16,23].…”

Soy isoflavones enhance radiotherapy in a metastatic prostate cancer model

“…5,16,17 The average consumption of soy isoflavones by Chinese or Japanese populations is estimated at 10-70 mg/day in contrast to about 1 mg/day estimated in Caucasian Americans. 18,19 Prostate tumors treated either with genistein or soy isoflavones showed similar histological findings including large areas of necrosis with numerous apoptotic cells and formation of giant abnormal cells as shown in our previous genistein studies. 8,9 In situ alterations induced by either the combination of radiation with soy isoflavones or genistein were comparable.…”

Intakes and sources of soya foods and isoflavones in a UK population cohort study (EPIC-Norfolk)

“…A study of 447 non-Asian women living in the San Francisco Bay Area estimated mean daily daidzein and genistein intakes of 1.3 mg and 1.5 mg, respectively, using a modified ffq and a newly constructed database (Horn-Ross et al, 2000). In the US, the dietary intake of genistein has been estimated at 1-3 mg/day (Adlercreutz, 1990) but median daily intakes of Chinese and Japanese women living in the US have been estimated as 3.51 and 7.15 mg, respectively (Greendale et al, 2002).…”