Supplementation with flaxseed alters estrogen metabolism in postmenopausal women to a greater extent than does supplementation with an equal amount of soy1-3 (original) (raw)
Soy phytoestrogens: impact on postmenopausal bone loss and mechanisms of action
Nutrition Reviews, 2008
Due to their ability to mimic the actions of mammalian estrogens, soy phytoestrogens have been proposed as potential therapeutic agents to aid in preventing postmenopausal bone loss. In vitro, phytoestrogens promote osteoblastogenesis and inhibit osteoclastogenesis. Although a relatively large number of intervention studies have been undertaken in animals and humans, the efficacy of phytoestrogens as bone-protective agents in vivo remains unclear. Differences in the bioactivities of individual phytoestrogens, differences in phytoestrogen metabolism and bioavailability within different study populations, and imprecise reporting of the dose of phytoestrogens administered in intervention studies may have contributed to the disparity in study findings.
Effects of Soy Isoflavones on Markers of Bone Turnover in Premenopausal and Postmenopausal Women 1
The Journal of Clinical Endocrinology & Metabolism, 2000
Soy isoflavones are hypothesized to exert hormonal effects in women and thus may play a role in bone metabolism throughout life. In 2 randomized, cross-over studies, 14 pre-and 17 postmenopausal women were given 3 soy protein isolates containing different amounts of isoflavones [control, 0.13; low isoflavone (low-iso), 1.00; and highiso, 2.01 mg/kg body wt⅐day, averaging 8, 65, and 130 mg/day, respectively], for over 3 months each. Food records, blood samples, and 24-h urine collections were obtained throughout the studies. The endpoints evaluated included plasma or serum concentrations of bone-specific alkaline phosphatase, osteocalcin, insulin-like growth factor-I (IGFI), IGF binding protein-3 (IGFBP3), and urine concentrations of deoxypyridinoline cross-links and carboxy-terminal telopeptide of type I collagen. In premenopausal women, IGFI and IGFBP3 concentrations were increased by the low-iso diet, and deoxypyridinoline cross-links was increased by both the low-and highiso diets during certain phases of the menstrual cycle. In postmenopausal women, bone-specific alkaline phosphatase was decreased by both the low-and high-iso diets, and there were trends toward decreased osteocalcin, IGFI, and IGFBP3 concentrations with increasing isoflavone consumption. Although soy isoflavones do affect markers of bone turnover, the changes observed were of small magnitude and not likely to be clinically relevant. These data do not support the hypothesis that dietary isoflavones per se exert beneficial effects on bone turnover in women. (J Clin Endocrinol Metab 85: 3043-3048, 2000)
Journal of Clinical Medicine
Postmenopausal osteoporosis is the most common form of osteoporosis and one of the major public health problems in developed countries. The prevalence of this condition, associated with the physiological stage of menopause, is continuously increasing. This study evaluated the effectiveness of soy isoflavones as compared to hormone replacement therapy (HRT) in low doses, on the prevention of postmenopausal osteoporosis, by determining bone mineral density (BMD) and urinary deoxypyridinoline (D-pyr) in physiological postmenopausal women. The study was conducted over a period of 12 months, on three parallel groups, which included a total of 325 postmenopausal women (HRT group: n = 95; phytoestrogens group: n = 124; control group: n = 106). At the one-year evaluation, we observed T-score normalization in a small number of cases (5.26%, 2.42% and 0.00%, respectively). The average values of D-Pyr decreased by 11.38% in the group treated with phytoestrogens (p < 0.05) and by 15.32% in t...
Bone, 2010
Introduction: Effects of soy isoflavone supplements on bone turnover markers remain unclear. This up-todate systematic review and meta-analysis of randomized controlled trials (RCTs) was performed primarily to more completely and precisely clarify the effects on urinary deoxypyridinoline (DPD) and serum bone alkaline phosphatase (BAP) and secondarily to evaluate the effects on other bone turnover markers, compared with placebo in menopausal women. Methods: PubMed, CENTRAL, ICHUSHI, and CNKI were searched in June 2009 for relevant studies of RCTs. Data on study design, participants, interventions, and outcomes were extracted and methodological quality of each included trial was assessed. Results: From 3740 identified relevant articles, 10 (887 participants), 10 (1210 participants), and 8 (380 participants) RCTs were selected for meta-analysis of effects on DPD, BAP, and serum osteocalcin (OC), respectively, using Review Manager 5.0.22. Daily ingestion of an average 56 mg soy isoflavones (aglycone equivalents) for 10 weeks to 12 months significantly decreased DPD by 14.1% (95% CI: −26.8% to −1.5%; P = 0.03) compared to baseline (heterogeneity: P b 0.00001; I 2 = 93%; random effects model). The overall effect of soy isoflavones on DPD compared with placebo was a significant decrease of −18.0% (95% CI: −28.4% to −7.7%, P = 0.0007; heterogeneity: P = 0.0001; I 2 = 73%; random effects model). Subgroup analyses and metaregressions revealed that isoflavone dose and intervention duration did not significantly relate to the variable effects on DPD. Daily supplementation of about 84 mg and 73 mg of soy isoflavones for up to 12 months insignificantly increased BAP by 8.0% (95% CI: −4.2% to 20.2%, P = 0.20; heterogeneity: P b 0.00001; I 2 =98%) and OC by 10.3% (95% CI: −3.1% to 23.7%, P = 0.13; heterogeneity: P =0.002; I 2 = 69%) compared with placebo (random effects model), respectively. Conclusions: Soy isoflavone supplements moderately decreased the bone resorption marker DPD, but did not affect bone formation markers BAP and OC in menopausal women. The effects varied between studies, and further studies are needed to address factors relating to the observed effects of soy isoflavones on DPD and to verify effects on other bone turnover markers.
2011
Summary Introduction: the results of the works published on the role of isoflavones in the prevention of postme- nopausal osteoporosis are contradictory. The objective of our study is to evaluate the effects of nutritio- nal intervention with a milk product enriched with soy isoflavones on bone metabolism in Spanish pos- tmenopausal women. Subjects and methods: a randomised controlled double blind trial was carried out in 99 postmenopausal women who were allocated to two groups: group S (n=48), with a consumption of a milk product enri- ched with soy isoflavones (50mg/day), and group C (n=51), with a consumption of a control milk pro- duct over 12 months. Hormone parameters and markers for bone metabolism were assessed at the base- line and at one year. Ultrasound of the calcaneum (QUS, Hologic Sahara ® , North Carolina, US.) was used as the evaluation tool for bone mass. Results: at 12 months, a decrease in blood levels of tartrate-resistant acid phosphatase and osteoprotege- rin o...
Nutrition and Cancer, 2018
Lignan intake, and its richest food source, flaxseed, have been associated with reduced breast cancer risk. Endogenous sex hormones, such as estrogens, play a role in breast cancer development, and lignans may alter these sex hormone levels. To assess the effect of flaxseed on circulating sex hormones, a randomized controlled trial was conducted among 99 postmenopausal women in Toronto, Canada. The intervention arm consumed 2 tablespoons (15 g) of ground flaxseed daily for 7 weeks; the control arm maintained usual diet. Baseline and week 7 concentrations of 14 serum sex hormones were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay, and serum enterolignans (lignan biomarker) using LC-MS/MS. Intervention effects on sex hormone levels were assessed using analysis of covariance. Serum enterolignans increased among the flaxseed arm (þ516%). Women consuming flaxseed (vs. controls) had increased serum 2-hydroxyestrone [treatment effect ratio (TER) ¼ 1.54; 95% CI: 1.18-2.00] and 2:16a-hydroxyestrone ratio (TER ¼1.54; 95% CI: 1.15-2.06); effects on other hormones were not statistically significant. Within the flaxseed arm, change in enterolignan level was positively correlated with changes in 2-hydroxyestrone and 2:16a-hydroxyestrone ratio, and negatively with prolactin. Findings suggest flaxseed affects certain circulating sex hormone levels with possible implications for future breast cancer prevention research.
American Journal of Epidemiology, 2002
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 µg/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). Am J Epidemiol 2002;155:746-54.
Nutrition journal, 2005
Osteoporosis is the gradual declining in bone mass with age, leading to increased bone fragility and fractures. Fractures in hip and spine are known to be the most important complication of the disease which leads in the annual mortality rate of 20% and serious morbidity rate of 50%. Menopause is one of the most common risk factors of osteoporosis. After menopause, sex hormone deficiency is associated with increased remodeling rate and negative bone balance, leading to accelerated bone loss and micro-architectural defects, resulting into increased bone fragility. Compounds with estrogen-like biological activity similar to "Isoflavones" present in plants especially soy, may reduce bone loss in postmenopausal women as they are similar in structure to estrogens. This research, therefore, was carried out to study the effects of Iranian soy protein on biochemical indicators of bone metabolism in osteopenic menopausal women. This clinical trial of before-after type was carried o...
American Journal of Clinical Nutrition, 2009
Background: Isoflavones are naturally occurring plant estrogens that are abundant in soy. Although purported to protect against bone loss, the efficacy of soy isoflavone supplementation in the prevention of osteoporosis in postmenopausal women remains controversial. Objective: Our aim was to test the effect of soy isoflavone supplementation on bone health. Design: A multicenter, randomized, double-blind, placebo-controlled 24-mo trial was conducted to assess the effects of daily supplementation with 80 or 120 mg of soy hypocotyl aglycone isoflavones plus calcium and vitamin D on bone changes in 403 postmenopausal women. Study subjects were tested annually and changes in whole-body and regional bone mineral density (BMD), bone mineral content (BMC), and T scores were assessed. Changes in serum biochemical markers of bone metabolism were also assessed. Results: After study site, soy intake, and pretreatment values were controlled for, subjects receiving a daily supplement with 120 mg soy isoflavones had a statistically significant smaller reduction in whole-body BMD than did the placebo group both at 1 y (P , 0.03) and at 2 y (P , 0.05) of treatment. Smaller decreases in whole-body BMD T score were observed among this group of women at 1 y (P , 0.03) but not at 2 y of treatment. When compared with the placebo, soy isoflavone supplementation had no effect on changes in regional BMD, BMC, T scores, or biochemical markers of bone metabolism. Conclusion: Daily supplementation with 120 mg soy hypocotyl isoflavones reduces whole-body bone loss but does not slow bone loss at common fracture sites in healthy postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00665860.
https://www.ijhsr.org/IJHSR\_Vol.9\_Issue.9\_Sep2019/IJHSR\_Abstract.023.html, 2019
Background:-Menopause is a natural event associated with gradual reduction of estrogen production. Decrease level of estrogen cause physical and psychological changes that effect women's health. Soybean contains phytoestrogen, which are similar to the hormone estrogen. There is substantial evidence that soybean have the potential to address changes associated with menopausal transition. Aim:-To investigate the effect of soy isoflavone consumption on bone metabolism and body composition in postmenopausal women of Udaipur city, Rajasthan. Materials and method:-Sixty postmenopausal women at medium risk of osteoporosis were randomly divided into two groups (30 in each) treatment and control. Treatment group was supplemented with 40 g soyflour containing 52.62 mg isoflavones for 16 weeks. Another group of 30 subjects served as control. Biochemical profile (alkaline phosphatase, estrone, estradiol) and body composition (BMI, WHR, body fat per cent, body fat mass and fat free mass) were estimated at initial level (0 day) and after 16 weeks. Results:-Results shows a significant increase in alkaline phosphatase, estrone, estradiol and fat free mass (p<0.05) and a significant (p<0.05) decrease in WHR in treatment group. Although there was a significant increase in weight and BMI also but it was still in the normal category. No significant changes in biochemical profile and body composition were found in the control group. Conclusion:-The study reveals that consumption of soyflour enhances bone formation and can have positive effect on improving muscle mass in osteoporotic postmenopausal women.