绝经妇女补充大豆异黄酮和钙后骨密度的改变及与ER基因Px单倍型的关系

目的 探讨绝经妇女补充大豆异黄酮和钙1年后骨密度(BMD)的改变及与雌激素受体(ER)基因Px单倍型的关系.方法 应用多聚酶链反应.限制性片段长度多态性(PCR-RFLP)检测691名汉族45～65岁绝经妇女的ER-α的PvuⅡ和Xba Ⅰ酶切位点多态性,从497名Pvu Ⅱ-Xba Ⅰ单倍体确定者中抽取93名进行为期1年的随机对照干预实验.根据基线时BMD测定结果,将T＜-1.5者纳入干预组(共52名),其余的作为观察组(共29名).将干预组对象随机分为2组:补钙+维生素D(VD)组和补钙+VD+大豆异黄酮组.给予的剂量分别为:钙440 mg/d;VD 100 IU/d;大豆异黄酮100 mg/d,正常观察组不给予任何特殊处理,干预期为12个月.采用双能X线吸收仪(DXEA)测量测定基线和终期腰椎及髋部的BMD.结果 试验结束后,观察组的绝经后妇女,全身、腰椎及股骨颈的BMD较基线时降低,变化率分别为-1.88%,-3.31%,-3.09%.ER-α的Px基因型全身BMD较基线时性降低2.44%,而non-Px基因型则无显著性改变.补钙组和补钙+大豆异黄酮组,全身及股骨颈的BMD都较基线时降低,但组间的变化率差异并无统计学意义;而腰椎、大转子的BMD较基线未有显著性的改变,甚至有略微升高.补钙和补大豆异黄酮对BMD的影响与ER-α的基因型无关.结论 妇女绝经后骨量开始丢失,丢失速率似乎与ER基因Px单倍型有相关性.已出现骨量减少的绝经后妇女补钙1年能降低骨量的丢失速率,但补充大豆异黄酮1年尚未观察到对BMD保护的作用.补钙及大豆异黄酮对BMD的干预效果与ER-α基因多态性无关.     

大豆异黄酮对更年期妇女骨密度影响

目的 拟通过人群膳食干预试验,从细胞因子水平研究植物雌激素大豆异黄酮对更年期妇女骨密度的作用。方法 随机双盲法将90名更年期妇女分为大豆异黄酮组观察和安慰剂对照组,每人每天服用大豆异黄酮90mg或者安慰剂,试验期限6个月。超声法测定爱试对象桡骨远端和胫肌中段的骨密度;酶联免疫学方法测定受试对象血清中细胞因子白介素-6(II-6)和肿瘤坏死因子-α(TNF-α)的水平。结果 服用大豆异酮组受试对象的胫骨骨密度增加明显,差异有统计学意义,安慰剂组受试对象骨密度差异无统计学意义;大豆异黄酮组受试对象血清中IL-6和TNF-α的水平在试验结束后均显著降低,差异有统计学意义(P<0.05)。结论 植物雌激素大豆异黄酮可有效增加更年期妇女骨骼密度,其机制可能是通过降低血清中细胞因子IL-6和TNF-α的水平实现的。     

大豆异黄酮干预对妇女骨密度影响的META分析

目的采用meta分析方法评估大豆异黄酮干预对妇女骨密度作用的随机对照试验研究的合并效应。方法以"植物雌激素"、"异黄酮"、"大豆"、"金雀素黄酮"和"骨"为主题词和关键词,检索1990年1月至2007年10月Medline、Pubmed及CNKI数据库发表的有关文献。纳入文献限定于在成年妇女中进行大豆异黄酮随机对照试验,且有干预前后骨密度值或改变值及其标准差或可信区间者。结果共纳入16篇文献,含1304名妇女,约91%为停经女性。结果发现,平均每天补充73mg异黄酮者的腰椎和总股骨骨密度的年均变化值(95%CI)比对照人群分别增加了18.3(6.0～30.6)和3.3(0.5～6.1)mg/cm2,相当于对应部位骨密度值的2.0%和0.4%;但对股骨颈骨密度无显著效应。亚组分析显示,该效应在干预剂量≥80mg/d者略好于小于80mg/d者;干预时间<1年者略好于≥1年者;剔出非绝经对象可轻微增加合并效应。结论大豆异黄酮干预可有效改善妇女腰椎及总股骨骨密度。     

营养素干预对绝经妇女骨质疏松的影响

目的 观察血脂正常但骨密度降低的绝经妇女补充钙、维生素D和大豆异黄酮后，机体骨密度和血脂成分的变化。方法 2004年4月从武汉郊区绝经妇女中筛选血脂正常伴骨量减少或骨质疏松的绝经妇女60名，随机均分为两干预组，每组30人。一组给予液体钙（含维生素D）；一组给予液体钙（含维生素D）和大豆异黄酮，跟踪观察一年。测定每位受试对象骨骼骨密度和血脂成分。结果 试验结束后，补钙组和补钙＋大豆异黄酮组，全身及股骨颈的骨密度（BMD）都较基线时显著降低（P〈0．05），组间变化无显著性差异（P〉0．05）；而腰椎、大转子BMD与基线相比，略微升高，但尚无统计学差异。补钙和补钙＋大豆异黄酮均能显著降低血总胆固醇（P〈0．05）。结论 对已出现骨量减少的绝经后妇女补钙一年能降低绝经后BMD的丢失速率，但补充大豆异黄酮一年尚未观察到对BMD的保护作用。绝经妇女补充钙和大豆异黄酮补可能干扰机体的血脂代谢。     

大豆异黄酮和钙对绝经妇女骨代谢的影响及与ER基因Px单倍型的关系

目的探讨补充大豆异黄酮和钙对绝经妇女骨代谢的影响及与ER基因Px单倍型的关系。方法应用多聚酶链反应-限制性片断长度多态性(PCR-RFLP)检测691名汉族45～65岁绝经妇女的ER-α的PvuII和XbaI酶切位点多态性,从497名PvuII-XbaI单倍体确定者中随机抽取93人测定BMD,将T<-1.5者纳为干预对象(共60人)进行为期一年的随机对照干预实验。将干预对象随机分为两组:补钙+VD组和补钙+VD+大豆异黄酮组。给予的剂量分别为:钙440mg/d;VD100IU/d;大豆异黄酮100mg/d,干预期为12mon。测定基线和终期的各项骨代谢生化指标。结果干预12个月后,补钙组和补钙+大豆异黄酮组,机体的雌激素水平均未见显著性的改变,而25-OH-D均水平升高(P=0.09),但两组间的变化率无显著性的差异;血清钙磷及反映骨形成的指标未见显著性改变。补钙组的抗酒石酸酸性磷酸酶-5b(Tracp-5b)较基线升高[变化率:23.4%(-22.9%～49.1%)],而补钙+大豆异黄酮组则较基线降低[变化率:-4.2%(-26.0%～17.6%)],两组的变化率有显著性差异(P<0.05),尿吡啶交联物(Pyd)和I型胶原N末端肽(NTx)则未见显著性改变。补钙组,non-Px基因型较Px基因型更容易出现Pyd升高,骨特异性碱性磷酸酶(BAP)降低。钙+大豆异黄酮的干预效果在两种基因型间没有差异.结论补充大豆异黄酮并不影响体内的雌激素水平。反应骨吸收的生化指标Tracp-5b对大豆异黄酮的作用较敏感。单纯补钙后骨代谢生化指标的改变受Px单倍体基因型的影响。     

大豆异黄酮对去势大鼠类雌激素样作用的研究

目的探讨植物雌激素大豆异黄酮对去卵巢大鼠生长发育、血液生化指标、骨营养状况及子宫增生的影响及作用机制。方法选择60只雌性SD大鼠进行腹腔假手术或切除双侧卵巢后,随机分为6组,每组10只,分别为假手术组、去卵巢对照组、雌激素对照组(β-雌二醇0.2 mg/kg.bw)和大豆异黄酮剂量为30、60、120 mg/kg.bw的高、中、低3个剂量组,分别用含有β-雌二醇、不同剂量大豆异黄酮的饲料和基础饲料喂养7周,实验期间记录各组大鼠的体重和摄食量,并计算食物利用率。实验结束后测定大鼠血清生化指标、股骨密度、骨钙含量,同时对子宫进行病理组织学观察。结果大豆异黄酮各剂量组大鼠的股骨中点和中、高剂量组远心点骨密度均高于去卵巢对照组(P<0.05或P<0.01);大豆异黄酮各剂量组的生长发育、血清生化指标、骨钙含量以及子宫萎缩程度与去卵巢对照组比较差异无统计学意义(P>0.05)。结论大豆异黄酮能够增加去势大鼠的骨密度,可有效防止卵巢切除大鼠的骨量丢失,具有类雌激素样作用,未见对子宫有明显的增生作用。     

不同ER-β基因型绝经妇女补充大豆异黄酮和钙后血脂的变化

目的观察血脂正常的不同ER基因型的绝经妇女补充钙和大豆异黄酮片剂(不含蛋白)一年后血脂的变化。方法从武汉郊区绝经妇女中筛选60名血脂正常但骨量减少或骨质疏松的绝经妇女为受试对象,随机分为两组,每组各30人,并确定其ER-β基因型别。一组给予液体钙440mg/d,VD 100IU/d;另一组给予液体钙440mg/d,VD 100IU/d和大豆异黄酮片剂100mg/d(不含蛋白),随访一年。测定每位受试对象各血脂成分,包括甘油三酯(TG)、总胆固醇(CHO)、低密度脂蛋白胆固醇(LDL)和高密度脂蛋白胆固醇(HDL)。结果补钙和补钙+大豆异黄酮组的血总胆固醇均显著降低(P<0.05)。在Rr/rr基因型绝经妇女中,补钙组TG平均增加了0.2mmol/L,补钙+大豆异黄酮组平均降低了0.44mmol/L,两者间差异有显著性(P<0.05)。结论足量的钙和适量的大豆异黄酮摄入不仅有益于绝经妇女的骨骼代谢,还有益于血脂代谢,且随ER-β基因酶切型别的不同而异。     

大豆饲料对去卵巢大鼠骨丢失的预防作用

[目的]研究大豆饲料对去卵巢大鼠骨丢失的预防作用。[方法]将大鼠分为假手术组、雌激素组、去卵巢对照组、去卵巢大豆膳食组(低、中、高剂量)。实验10周后进行骨密度以及骨组织形态学测量。[结果]假手术组、雌激素对照组、中及高剂量组骨密度高于去卵巢对照组和低剂量组(P<0.05);中、高剂量组骨密度低干假手术组和雌激素组(P<0.05);与假手术组和雌激素对照组相比,去卵巢对照组和低、中、高剂量组骨小梁面积百分率降低、骨小梁数目减少、骨小梁间隔增宽(P<0.05);与中、高剂量组相比,去卵巢对照组和低剂量组骨小梁面积百分率降低、骨小梁数目减少、骨小梁间隔增宽(P<0.05)。[结论]大豆饲料具有预防去卵巢大鼠骨丢失的作用。     

大豆异黄酮对去势大鼠骨代谢的影响

[目的]探讨大豆异黄酮改善激素缺乏大鼠骨营养状况及作用机制。[方法]选用卵巢切除大鼠所诱发的骨质疏松模型,给予大豆异黄酮治疗,同时设假手术组及模型对照组。3个月后测定大鼠骨密度、骨钙含量及骨代谢酶学指标。[结果]大豆异黄酮可提高去势大鼠的骨密度、骨钙含量;降低血清碱性磷酸酶(AKP)及抗酒石酸酸性磷酸酶(TRACP)的活性(P<0.05),其作用与剂量有关。[结论]大豆异黄酮能够增加去势大鼠的骨密度,有类似雌激素样作用,可有效防治卵巢切除大鼠的骨量丢失,其作用机制可能是通过降低骨转换率来实现。     

低雌激素水平对绝经后妇女血压、血脂及骨密度的影响

目的探讨低雌激素(E2)水平对绝经后妇女血压、血脂及骨密度的影响,为卵巢早衰患者低雌激素的治疗、预防或治疗结局的改善提供理论依据。方法选取2016年8月-2017年8月在新疆医科大学第一附属医院就诊的绝经后组妇女110例,卵巢早衰组20例,绝经过渡期组61例,卵巢早衰过渡期组19例,比较各组妇女血脂、雌激素、腰椎总骨密度的差异。结果卵巢早衰组妇女E2水平(80.21±40.06)pmol/L明显低于绝经后组、绝经过渡期组和卵巢早衰过渡期组,差异均有统计学意义(P<0.05);收缩压(SBP)和腰椎总骨密度分别为(121.58±14.55)mmHg和(0.79±0.14)g/cm2明显低于绝经后组、绝经过渡期组和卵巢早衰过渡期组,差异均有统计学意义(P<0.05);高密度脂蛋白胆固醇(HDL-C)水平(1.16±0.28)mmol/L,明显低于绝经后组、绝经过渡期组和卵巢早衰过渡期组,差异均有统计学意义(P<0.05)。E2水平与腰椎总骨密度呈正相关(R=0.322,P<0.05),而与血压、血脂无明显关系(P>0.05)。结论卵巢早衰妇女雌激素明显低于正常绝经妇女,且两者血压、血脂和骨密度有所差异;雌激素与骨密度有密切关系。     

Soy isoflavones attenuate bone loss in early postmenopausal Chinese women

Background Previous studies show that daily doses of 40–99 mg soy isoflavones produce inconsistent effects on preventing estrogen-related bone loss in postmenopausal women. Aim of the study To examined the bone-sparing effect of isoflavones at a higher dose in early Chinese postmenopausal women. Methods A total of 90 eligible women aged 45–60 years were randomly assigned to three treatment groups (30 subjects/group) with daily dosages of 0 (placebo), 84 and 126 mg isoflavones for 6 months. Further inclusion criteria included body mass index <30 kg/m² and Kuppermann Climacteric Scale >15. Bone mineral density (BMD) of the spine and hip were measured using dual- energy X-ray absorptiometry at 0 and 6 months. Serum osteocalcin, bone-specific alkaline phosphatase (BAP) and urinary deoxypyridinoline were examined at 0, 3 and 6 months. Results Mean percent changes in BMD at the lumbar spine (p = 0.114) and femoral neck (p = 0.053) increased with the supplementations of soy isoflavones after adjusting for age, years since menopause, body weight and height, dietary intakes of isoflavones, calcium and protein, physical activities and baseline BMD at the relevant sites. We observed significantly dose-dependent linear relationship between the supplemental isoflavones and percent changes of BMD at the spine (p = 0.042) and femoral neck (p = 0.016) post-treatment, and urinary total deoxypyridinoline (p = 0.014) at 12 weeks but not at 24 weeks after adjusting for the above factors. No significant difference in percent changes in serum osteocalcin (p > 0.05) and BAP (p > 0.05) was found among the three treatment groups at 12-week and 24-week post-treatment. Conclusion There is a significantly dose-dependent effect of soy isoflavones on attenuating bone loss at the spine and femoral neck possibly via the inhibition of bone resorption in non-obese postmenopausal Chinese women with high Kuppermann Scale.     

Soymilk or progesterone for prevention of bone loss

BACKGROUND: Given concerns over the use of hormone replacement therapy (HRT), women are seeking natural alternatives to cope with the symptoms and effects of menopause. The bone sparing effects of soy protein and its isoflavones is well established in animal studies, while 5 previous human studies on soy and bone have yielded variable outcomes due in part to their short duration of study. Progesterone has been suggested as a bone-trophic hormone, but the effect of long-term, low dose transdermal progesterone is unknown. AIM: The aim of the study was to compare for the first time the long-term effects of soymilk, with or without isoflavones with natural transdermal progesterone, or the combination, on bone mineral density in the lumbar spine and hip. METHODS: Postmenopausal, Caucasian women with established osteoporosis or at least 3 risk-factors for osteoporosis, were randomly assigned, double-blind to one of four treatment-groups: soymilk containing isoflavones (soy+, n = 23), transdermal progesterone (TPD+, n = 22), or the combination of soy+ and TDP+,(n = 22) or placebo (isoflavone-poor soymilk, soy/ and progesterone-free-cream TDP/, n = 22). All subjects received comparable intakes of calcium, minerals and vitamins. Bone mineral content (BMC) and density (BMD) were measured in lumbar spine and hip by using dual-energy X-ray absorptiometry (DEXA) at baseline and after 2 years. FINDINGS: The percentage change in lumbar spine BMD and BMC respectively, did not differ from zero in the soy+ group (+1.1%, +2.0%) and TDP+ group (/1.1%, +0.4 %) but significant bone loss occurred in the control group (/4.2%,/4.3 %) and the combined treatment group (/2.8%, /2.4 %). No significant changes occurred for femoral neck BMD or BMC. INTERPRETATION: Daily intake of two glasses of soymilk containing 76 mg isoflavones prevents lumbar spine bone loss in postmenopausal women. Transdermal progesterone had bone-sparing effects but when combined with soy milk a negative interaction between the two treatments occurs resulting in bone-loss to a greater extent than either treatment alone.     

Isoflavone-rich soy protein isolate attenuates bone loss in the lumbar spine of perimenopausal women

BACKGROUND: No published studies have directly examined the effect of soy protein with isoflavones on bone or bone turnover in perimenopausal women. OBJECTIVE: Our objective was to determine the effects of 24 wk of consumption of soy protein isolate with isoflavones (80.4 mg/d) in attenuating bone loss during the menopausal transition. DESIGN: Perimenopausal subjects were randomly assigned, double blind, to treatment: isoflavone-rich soy (SPI+; n = 24), isoflavone-poor soy (SPI-; n = 24), or whey (control; n = 21) protein. At baseline and posttreatment, lumbar spine bone mineral density (BMD) and bone mineral content (BMC) were measured by using dual-energy X-ray absorptiometry. At baseline, midtreatment, and posttreatment, urinary N:-telopeptides and serum bone-specific alkaline phosphatase (BAP) were measured. RESULTS: The percentage change in lumbar spine BMD and BMC, respectively, did not differ from zero in the SPI+ or SPI- groups, but loss occurred in the control group (-1.28%, P: = 0.0041; -1.73%, P: = 0.0037). By regression analysis, SPI+ treatment had a positive effect on change in BMD (5.6%; P: = 0.023) and BMC (10.1%; P: = 0.0032). Baseline BMD and BMC (P: < or = 0.0001) negatively affected the percentage change in their respective models; baseline body weight (P: = 0.0036) and bone-free lean weight (P: = 0.016) contributed positively to percentage change in BMD and BMC, respectively. Serum BAP posttreatment was negatively related to percentage change in BMD (P: = 0.0016) and BMC (P: = 0.019). Contrast coding using analyses of covariance with BMD or BMC as the outcome showed that isoflavones, not soy protein, exerted the effect. CONCLUSION: Soy isoflavones attenuated bone loss from the lumbar spine in perimenopausal women.     

膳食钙、磷以及奶制品对绝经后妇女骨密度的影响

目的探讨膳食中钙、磷以及奶制品的摄入量对骨密度及骨盐含量的影响,为研究骨质疏松的预防提供相关线索和依据。方法在广州市越秀区农林街社区发放传单招募调查对象,并采用自编的结构化标准问卷,对320名广州绝经后妇女的膳食习惯进行调查,并测量其全身、股骨全身、股骨颈、股骨干、大粗隆、Ward’s三角以及腰锥1～4的骨密度和骨量,采用多因素逐步回归分析探讨膳食钙、磷及奶制品对骨盐含量及骨密度的影响。结果 320名调查对象平均57.1岁,平均绝经年限7.3年,平均每天摄入钙、磷及奶制品分别为822 mg、949 mg和126 g,平均全身骨密度为1.054 g/cm2,磷与7个部位的骨密度及骨盐含量呈正相关关系（P〈0.05）。随着磷摄入量增加,全身及腰锥1～4骨密度增加,偏回归系数值分别为0.121和0.184 g.（cm2）-1.g-1.d-1。随着奶制品摄入量增加,股骨全身、股骨干骨密度也相应增加,骨密度偏回归系数值分别为0.686、0.841mg.（cm2）-1.g-1.d-1。钙与全身、股骨全身、股骨颈、大粗隆、股骨干和Ward’s三角的BMC具有正相关性,而在钙与BMD关系中,钙只与股骨全身、大粗隆和股骨干呈正相关性,且每日膳食中每增加100 g钙的摄入量,则股骨全身、大粗隆、股骨干的骨密度相应增加5.3、4.8和7.6 g/cm2。结论增加膳食中钙、磷以及奶制品的摄入量有利于绝经后妇女的骨盐含量及骨密度的提高。     

Beneficial effects of soybean isoflavone supplementation on bone metabolism and serum lipids in postmenopausal japanese women: a four-week study

OBJECTIVE: The aim of this study was to determine the effects of soy isoflavones with weak estrogen-like activities both on bone metabolism and on serum lipids in perimenopausal women. METHODS: Twenty-three healthy perimenopausal women were assigned randomly to either isoflavone or placebo groups. The isoflavone group (n = 12) received daily capsules of soy isoflavone extract (61.8 mg of isoflavones) and the placebo group (n = 11) received daily placebo capsules for four weeks. Urinary excretion of isoflavone was measured at weeks 0, 2 and 4. Urinary excretion of pyridinoline and deoxypyridinoline, bone stiffness and levels of serum cholesterol, triglyceride and cholesterol fractions were measured at weeks 0 and 4. RESULTS: As compared to the placebo group, urinary isoflavone, primarily daidzein, excretion was increased at weeks 2 and 4 in the isoflavone group. Excretion of bone resorption markers was reduced significantly in the isoflavone group. Both total serum cholesterol and LDL cholesterol were decreased significantly in the isoflavone group. Other serum biochemical parameters were not changed in either group. CONCLUSION: Soy isoflavone supplementation for four weeks showed potentially beneficial effects on bone metabolism and on serum lipids in perimenopausal women. These effects could have the potential to reduce the risks of postmenopausal osteoporosis and of cardiovascular diseases in such women.     

Soybean Isoflavones Reduce Postmenopausal Bone Resorption in Female Japanese Immigrants in Brazil: A Ten-Week Study

Objective: Some human studies and animal models of experimental osteoporosis have shown that soy isoflavones may be effective on bone health. In this study, we carried out an intervention study to explore the effects of dietary isoflavone on bone metabolism.

Methods: Forty healthy female postmenopausal Japanese immigrants living in Brazil were divided into two groups: isoflavone-administered (n = 20) or placebo (n = 20). Subjects in the isoflavone-administered group ingested 37.3 mg per day for 10 weeks. The collection of 24-hour urine and the measurement of bone stiffness were performed at 0 and 10 weeks. Urinary excretion of isoflavones and bone resorption markers were analyzed.

Results: Urinary isoflavone excretion in the isoflavone-administered group was significantly increased at weeks 3 and 10. Urinary excretion of bone resorption markers was reduced in the isoflavone-administered group, while the placebo group did not show any significant reduction. Differences in levels of urinary isoflavones and bone resorption markers between the two groups were significant.

Conclusion: This study demonstrated that the bone resorption was associated with the intake of soy isoflavones in postmenopausal women, and continuous dietary intake of isoflavone may inhibit postmenopausal osteoporosis.     

The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial

BACKGROUND: Isoflavone phytoestrogen therapy has been proposed as a natural alternative to hormone replacement therapy (HRT). HRT has a beneficial effect on bone, but few trials in humans have investigated the effects of isoflavones on bone. OBJECTIVE: The objective of the study was to determine the effect on bone density of a red clover-derived isoflavone supplement that provided a daily dose of 26 mg biochanin A, 16 mg formononetin, 1 mg genistein, and 0.5 mg daidzein for 1 y. Effects on biochemical markers of bone turnover and body composition were also studied. DESIGN: Women aged 49-65 y (n = 205) were enrolled in a double-blind, randomized, placebo-controlled trial; 177 completed the trial. Bone density, body composition, bone turnover markers, and diet were measured at baseline and after 12 mo. RESULTS: Loss of lumbar spine bone mineral content and bone mineral density was significantly (P = 0.04 and P = 0.03, respectively) lower in the women taking the isoflavone supplement than in those taking the placebo. There were no significant treatment effects on hip bone mineral content or bone mineral density, markers of bone resorption, or body composition, but bone formation markers were significantly increased (P = 0.04 and P = 0.01 for bone-specific alkaline phosphatase and N-propeptide of collagen type I, respectively) in the intervention group compared with placebo in postmenopausal women. Interactions between treatment group and menopausal status with respect to changes in other outcomes were not significant. CONCLUSION: These data suggest that, through attenuation of bone loss, isoflavones have a potentially protective effect on the lumbar spine in women.     

Soybean isoflavones reduce postmenopausal bone resorption in female Japanese immigrants in Brazil: a ten-week study

OBJECTIVE: Some human studies and animal models of experimental osteoporosis have shown that soy isoflavones may be effective on bone health. In this study, we carried out an intervention study to explore the effects of dietary isoflavone on bone metabolism. METHODS: Forty healthy female postmenopausal Japanese immigrants living in Brazil were divided into two groups: isoflavone-administered (n = 20) or placebo (n = 20). Subjects in the isoflavone-administered group ingested 37.3 mg per day for 10 weeks. The collection of 24-hour urine and the measurement of bone stiffness were performed at 0 and 10 weeks. Urinary excretion of isoflavones and bone resorption markers were analyzed. RESULTS: Urinary isoflavone excretion in the isoflavone-administered group was significantly increased at weeks 3 and 10. Urinary excretion of bone resorption markers was reduced in the isoflavone-administered group, while the placebo group did not show any significant reduction. Differences in levels of urinary isoflavones and bone resorption markers between the two groups were significant. CONCLUSION: This study demonstrated that the bone resorption was associated with the intake of soy isoflavones in postmenopausal women, and continuous dietary intake of isoflavone may inhibit postmenopausal osteoporosis.     

Soy Isoflavones: No Effects on Bone Mineral Content and Bone Mineral Density in Healthy,Menstruating Young Adult Women after One Year

Background: The effects of isoflavone-enriched soy protein on human bone mineral content (mass) and density in healthy, menstruating young adult females have not been examined in a comparative prospective investigation. Peri- and post-menopausal women have been reported to show beneficial effects of isoflavones on bone measurements. Therefore, young women may also be able to improve their accrual of peak bone mineral content (BMC) and bone mineral density (BMD) during the early adult years of bone consolidation with an isoflavone-enriched diet.

Objectives: In this controlled, double-blind intervention, we tested the hypothesis that an isoflavone-rich soy protein diet increases BMC and BMD in young adult females over a period of one year in comparison to a control group receiving soy protein that has isoflavones removed.

Design: Young healthy women of any ethnic background, 21 to 25 years of age, were divided into two groups, placebo (n = 13) and supplement (n = 15). The soy protein supplement was enriched with isoflavones (～90 mg of total isoflavones/day), whereas the control protein diet was isoflavone-deficient, even though it contained the same amount of soy protein and other ingredients as the isoflavone-rich diet. Dual-energy x-ray absorptiometric (DXA) measurements of BMC and BMD were made at baseline and at 6 and 12 months. DXA estimates of body composition, including fat mass and lean body mass, were generated from whole-body BMC measurements. BMI was calculated as weight (kg) over height (m) squared. Physical activity was assessed, and three-day dietary records were taken at entry (baseline) and at 6 and 12 months.

Results: No changes in BMD after 12 months were found in either the isoflavone-treated (treatment) group or the isoflavone-deficient (control) group. Other variables also remained essentially constant over the 12-month period, including normal menstrual patterns in both the treatment and control groups.

Conclusions: The isoflavone-rich soy preparation had no effects on BMC and BMD over a 12-month period in young healthy adult females with normal menses. An isoflavone-rich supplement appears to have little or no effect on bone in young adult women with normal ovarian function, at least over this 12-month study period.