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)
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The Journal of Clinical Endocrinology & Metabolism, 2005
Phytoestrogens are increasingly incorporated into the diet of menopausal women. However, there are limited data on the efficacy of flaxseed on the consequences of estrogen deficiency in menopausal women. The purpose of the study was to assess the effects of flaxseed incorporation into the diet of healthy menopausal women. One hundred and ninety-nine menopausal women were randomly assigned to consume 40 g flaxseed/d (n ؍ 101) or wheat germ placebo (n ؍ 98) for 12 months. At baseline and at month 12, serum levels of lipids, bone mineral density (BMD), and menopausal symptoms were evaluated. Statistical analysis was performed under the intention to treat principle. Flaxseed reduced serum total
Effect of Dietary Flaxseed on Serum Levels of Estrogens and Androgens in Postmenopausal Women
Nutrition and Cancer, 2008
Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert breast cancer preventive effects through hormonal mechanisms. Our aim was to study the effects of flaxseed on serum sex hormones implicated in the development of breast cancer. Forty-eight postmenopausal women participated in a 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for the first 6 wk and 15.0 grams/day for an additional 6 wk. Nonsignificant declines were noted over the 12 wk (95% confidence intervals) for estradiol (pg/ml), estrone (pg/ml), and testosterone (pg/ml): -4.4 (-12.6 to 3.9), -3.3 (-7.7 to 1.2), -4.7 (-17.8 to 8.5), respectively. Changes tended to be more pronounced in overweight/obese women, particularly for estrone (-6.5, -11.9 to -1.2; P = .02). Our results suggest that dietary flaxseed may modestly lower serum levels of sex steroid hormones, especially in overweight/obese women.
The Journal of Clinical Endocrinology & Metabolism, 2002
The risk of cardiovascular disease and osteoporosis drastically increases at the onset of menopause. Phytoestrogens have been suggested to inhibit bone loss and protect the cardiovascular system, in part by improving lipid profiles. The purpose of the present study was to examine the effects of flaxseed, a rich source of the phytoestrogens called lignans, on lipid metabolism and biomarkers of bone turnover in postmenopausal women. Postmenopausal women who were not on hormone replacement therapy were assigned to one of two treatment groups in a double-blind randomized study. Women were asked to consume 40 g of either ground flaxseed or wheat-based comparative control regimen daily for 3 months. In addition, all subjects received 1,000 mg calcium and 400 IU vitamin D daily. Flaxseed supplementation lowered (P < 0.05) both serum total cholesterol and non-high-density lipoprotein cholesterol by 6%, whereas the comparative control regimen had no such effect. Flaxseed regimen reduced serum levels of both low-density-and high-density-lipoprotein cholesterol by 4.7% and triglyceride by 12.8%, albeit not statistically significant. Serum apolipoprotein A-1 and apolipoprotein B concentrations were significantly (P < 0.005) reduced by 6 and 7.5%, respectively, by the flaxseed regimen. Markers of bone formation and resorption were not affected by either of the treatments. The findings of this study indicate that flaxseed supplementation improves lipid profiles but has no effect on biomarkers of bone metabolism in postmenopausal women.
Soy Reduces Bone Turnover Markers in Women During Early Menopause: A Randomized Controlled Trial
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2016
Menopausal estrogen loss leads to an increased bone loss. Soy isoflavones can act as selective estrogen receptor modulators, their role in bone turnover is unclear. The primary outcome was assessing changes in plasma bone turnover markers. The secondary outcomes were assessing changes in cardiovascular risk markers including insulin resistance, blood pressure, and lipid profile. We performed a double-blind randomized parallel study in which 200 women within 2 years after the onset of their menopause were randomized to 15 g soy protein with 66 mg isoflavone (SPI) or 15 g soy protein alone (SP), daily for 6 months. There was a significant reduction in type I collagen crosslinked beta C-telopeptide (βCTX) (bone-resorption marker) with SPI supplementation (0.40 ± 0.17 versus 0.15 ± 0.09 μg/L; p < 0.01) compared to SP supplementation (0.35 ± 0.12 versus 0.35 ± 0.13 μg/L; p = 0.92) after 6 months. There was also a significant reduction in type I procollagen-N-propeptide (P1NP) (bone fo...
Nutr Rev, 2008
Plant-derived phytoestrogens are considered to be an alternative therapy for the prevention and control of bone loss in postmenopausal women. However, there are contradictory findings among clinical studies in the efficacy of soy isoflavones on bone metabolism in postmenopausal women. Inter-individual differences in gut bacteria metabolism of isoflavones to produce equol (the equol-producing phenotype) might partly explain these discrepancies. Among several trials in this area of research, few studies took the equolproducing phenotype into consideration, and those studies support the importance of this phenotype in the effect of soy isoflavones on bone health among postmenopausal women. Greater consideration of the equol-producing phenotype in the design of studies investigating the effect of soy isoflavones on bone health of postmenopausal women may provide more useful information.
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...