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The efficacy of soy isoflavones combined with soy protein on serum concentration of interleukin-6 and tumour necrosis factor-α among post-menopausal women? A systematic review and meta-analysis of randomized controlled trials.
Gholami, A, Mollanoroozy, E, Reza Baradaran, H, Hariri, M
Clinical and experimental pharmacology & physiology. 2022;(1):10-24
Abstract
The post-menopausal stage in women's life is associated with the enhancement of inflammation that may be reduced using soy isoflavones or soy protein. The present study aimed to summarize the effect of soy isoflavones plus soy protein on circulating interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) in post-menopausal women. The English-language articles were identified from the databases such as Cochrane Library, clinicaltrials.gov, Web of Science, PubMed, and Scopus until December 2020. The mean change from baseline and its standard deviation (SD) for intervention and comparison groups were used to calculate the effect size. The statistical heterogeneity of the intervention effects was computing by Cochran's Q test and I2 statistic. Nine and seven studies were selected for systematic review and meta-analysis, respectively. The results of our meta-analysis indicated a non-significant effect on the serum concentrations of IL-6 and TNF-α (weighted mean differences [WMD] = 0.07 pg/mL; 95% confidence interval [CI] = -0.03, 0.17 pg/mL; P = 0.190; WMD =0.05 pg/mL; 95% CI = -0.01, 0.12 pg/mL; P = 0.092; respectively). In subgroup analysis, soy isoflavones plus soy protein could increase the serum concentration of IL-6 in studies with soy isoflavones dose ≤87 mg/days, cross-over design, weak quality, and studies on participants who had health risk factors or diseases. The serum concentration of TNF-α increased in studies with cross-over design, intervention duration ≤56 days, and body mass index (BMI) >27, and in studies that were conducted on at-risk or sick participants. In conclusion, our meta-analysis did not confirm any significant effect on serum concentration of IL-6 and TNF-α among post-menopausal women.
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Effects of Soy Protein Containing of Isoflavones and Isoflavones Extract on Plasma Lipid Profile in Postmenopausal Women as a Potential Prevention Factor in Cardiovascular Diseases: Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Barańska, A, Błaszczuk, A, Kanadys, W, Baczewska, B, Jędrych, M, Wawryk-Gawda, E, Polz-Dacewicz, M
Nutrients. 2021;(8)
Abstract
The aim of the report was to evaluate the impact of soy protein containing isoflavones and soy isoflavones extract on lipid profile in postmenopausal women, as compared with placebo or protein of milk, casein or isolated soy protein with or without trace isoflavone content. We used the following databases: MEDLINE (PubMed), EMBASE and the Cochrane Library. Quantitative data synthesis was performed by applying a random-effects model. Subgroup analysis and meta-regression were performed to assess the modifiers of treatment response. In total, in the analysis studies, 2305 postmenopausal women took part. Changes in the lipid profile showed statistically significant decreases of total cholesterol by -0.12 (95% CI: -0.21, -0.03) mmol/L, -4.64 (95% CI: -8.12, -1.16) mg/dL, p = 0.01 and increased HDL-cholesterol by 0.03 (95% CI: 0.00, 0.06) mmol/L, 1.15 (95% CI: 0.00, 1.93) mg/dL, p = 0.05, as well as in LDL-cholesterol -0.05 (95% CI: -0.11, 0.01) mmol/L, -1.93 (95% CI: -4.25, 0.39) mg/dL, p = 0.08 and triacylglycerols -0.07 (95% CI: -0.14, 0.00) mmol/L, -6.123 (95% CI: -12.25, 0.00) mg/dL, p = 0.06. Our results suggests that soy and its isoflavones can be effective in correction changes in lipid metabolism in postmenopausal women and may favorably influence in preventing cardiovascular events.
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Soy intake and breast cancer risk: a prospective study of 300,000 Chinese women and a dose-response meta-analysis.
Wei, Y, Lv, J, Guo, Y, Bian, Z, Gao, M, Du, H, Yang, L, Chen, Y, Zhang, X, Wang, T, et al
European journal of epidemiology. 2020;(6):567-578
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Abstract
Epidemiological evidence on the association of soy intake with breast cancer risk is still inconsistent due to different soy intake levels across previous studies and small number of breast cancer cases. We aimed to investigate this issue by analyzing data from the China Kadoorie Biobank (CKB) study and conducting a dose-response meta-analysis to integrate existing evidence. The CKB study included over 300,000 women aged 30-79 from 10 regions across China enrolled between 2004 and 2008, and followed-up for breast cancer events until 31 December 2016. Information on soy intake was collected from baseline, two resurveys and twelve 24-h dietary recalls. We also searched for relevant prospective cohort studies to do a dose-response meta-analysis. The mean (SD) soy intake was 9.4 (5.4) mg/day soy isoflavones among CKB women. During 10 years of follow-up, 2289 women developed breast cancers. The multivariable-adjusted relative risk was 1.00 (95% confidence interval [CI] 0.81-1.22) for the fourth (19.1 mg/day) versus the first (4.5 mg/day) soy isoflavone intake quartile. Meta-analysis of prospective studies found that each 10 mg/day increment in soy isoflavone intake was associated with a 3% (95% CI 1-5%) reduced risk of breast cancer. The CKB study demonstrated that moderate soy intake was not associated with breast cancer risk among Chinese women. Higher amount of soy intake might provide reasonable benefits for the prevention of breast cancer.
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Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies.
Nachvak, SM, Moradi, S, Anjom-Shoae, J, Rahmani, J, Nasiri, M, Maleki, V, Sadeghi, O
Journal of the Academy of Nutrition and Dietetics. 2019;(9):1483-1500.e17
Abstract
OBJECTIVE We conducted a systematic review and dose-response meta-analysis of prospective studies to summarize findings on the associations between intakes of soy, soy isoflavones, and soy protein and risk of mortality from all causes, cancers, and cardiovascular diseases. METHODS Online databases were systematically searched to identify relevant articles published earlier than May 2018. We applied restricted cubic splines using random-effects analysis to assess dose-response associations. Between-study heterogeneity was assessed by I2 value and Cochrane Q test. Potential publication bias was assessed by visual inspection of funnel plots and Begg regression test. RESULTS In total, 23 prospective studies with an overall sample size of 330,826 participants were included in the current systematic review and the meta-analysis. Soy/soy products consumption was inversely associated with deaths from cancers (pooled relative risk 0.88, 95% CI 0.79 to 0.99; P=0.03; I2=47.1%, 95% CI 0.0% to 75.4%) and cardiovascular diseases (pooled effect size: 0.85, 95% CI 0.72 to 0.99; P=0.04; I2=50.0%, 95% CI 0.0% to 77.6%). Such significant associations were also observed for all-cause mortality in some subgroups of the included studies, particularly those with higher quality. In addition, higher intake of soy was associated with decreased risk of mortality from gastric, colorectal, and lung cancers as well as ischemic cardiovascular diseases. Participants in the highest category of dietary soy isoflavones intake had a 10% lower risk of all-cause mortality compared with those in the lowest category. We also found that a 10-mg/day increase in intake of soy isoflavones was associated with 7% and 9% decreased risk of mortality from all cancers and also breast cancer respectively. Furthermore, a 12% reduction in breast cancer death was indicated for each 5-g/day increase in consumption of soy protein. However, intake of soy protein was not significantly associated with all-cause and cardiovascular diseases mortality. CONCLUSIONS Soy and its isoflavones may favorably influence risk of mortality. In addition, soy protein intake was associated with a decreased risk in the mortality of breast cancer. Our findings may support the current recommendations to increase intake of soy for greater longevity.
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Soy and isoflavones consumption and breast cancer survival and recurrence: a systematic review and meta-analysis.
Qiu, S, Jiang, C
European journal of nutrition. 2019;(8):3079-3090
Abstract
BACKGROUND Some studies have investigated the association between soy and isoflavones consumption and breast cancer survival, but the results are far from conclusive. Accordingly, we performed a systematic review and meta-analysis to explore this issue. METHODS We performed a comprehensive search of Web of Science, PubMed, and Embase from inception to January 2018. The summary hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using a random effects model. RESULTS A total of 12 articles were included, which reported overall survival (OS), breast cancer specific survival (BCSS), and recurrence in 5770, 2386, and 1500 cases, respectively, among 37,275 women with breast cancer. The summary HR (95% CI) for the association (highest vs. lowest) of pre-diagnosis soy and isoflavones consumption with OS and BCSS was 0.84 (0.71-0.98) and 0.89 (0.74-1.07), respectively. Stratified analyses suggested that the reduced OS was more easily detected in studies that focused on post-menopausal patients. No significant association was found between post-diagnosis soy and isoflavones consumption with OS and BCSS, with summary HRs (95% CIs) of 0.80 (0.62-1.04) and 0.83 (0.64-1.07), respectively. Pre- and post-diagnosis soy isoflavones consumption were associated with reduced risk of recurrence. CONCLUSION This study provides limited evidence that pre-diagnosis soy and isoflavones intake is associated with a small reduction in post-menopausal breast cancer OS.
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A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases Circulating LDL and Total Cholesterol Concentrations in Adults.
Blanco Mejia, S, Messina, M, Li, SS, Viguiliouk, E, Chiavaroli, L, Khan, TA, Srichaikul, K, Mirrahimi, A, Sievenpiper, JL, Kris-Etherton, P, et al
The Journal of nutrition. 2019;(6):968-981
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Abstract
BACKGROUND Certain plant foods (nuts and soy protein) and food components (viscous fibers and plant sterols) have been permitted by the FDA to carry a heart health claim based on their cholesterol-lowering ability. The FDA is currently considering revoking the heart health claim for soy protein due to a perceived lack of consistent LDL cholesterol reduction in randomized controlled trials. OBJECTIVE We performed a meta-analysis of the 46 controlled trials on which the FDA will base its decision to revoke the heart health claim for soy protein. METHODS We included the 46 trials on adult men and women, with baseline circulating LDL cholesterol concentrations ranging from 110 to 201 mg/dL, as identified by the FDA, that studied the effects of soy protein on LDL cholesterol and total cholesterol (TC) compared with non-soy protein. Two independent reviewers extracted relevant data. Data were pooled by the generic inverse variance method with a random effects model and expressed as mean differences with 95% CI. Heterogeneity was assessed and quantified. RESULTS Of the 46 trials identified by the FDA, 43 provided data for meta-analyses. Of these, 41 provided data for LDL cholesterol, and all 43 provided data for TC. Soy protein at a median dose of 25 g/d during a median follow-up of 6 wk decreased LDL cholesterol by 4.76 mg/dL (95% CI: -6.71, -2.80 mg/dL, P < 0.0001; I2 = 55%, P < 0.0001) and decreased TC by 6.41 mg/dL (95% CI: -9.30, -3.52 mg/dL, P < 0.0001; I2 = 74%, P < 0.0001) compared with non-soy protein controls. There was no dose-response effect or evidence of publication bias for either outcome. Inspection of the individual trial estimates indicated most trials (∼75%) showed a reduction in LDL cholesterol (range: -0.77 to -58.60 mg/dL), although only a minority of these were individually statistically significant. CONCLUSIONS Soy protein significantly reduced LDL cholesterol by approximately 3-4% in adults. Our data support the advice given to the general public internationally to increase plant protein intake. This trial was registered at clinicaltrials.gov as NCT03468127.
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Cumulative Meta-Analysis of the Soy Effect Over Time.
Jenkins, DJA, Blanco Mejia, S, Chiavaroli, L, Viguiliouk, E, Li, SS, Kendall, CWC, Vuksan, V, Sievenpiper, JL
Journal of the American Heart Association. 2019;(13):e012458
Abstract
Background Soy protein foods have attracted attention as useful plant protein foods with mild cholesterol-lowering effects that are suitable for inclusion in therapeutic diets. But on the basis of the lack of consistency in significant cholesterol reduction by soy in 46 randomized controlled trials, the US Food and Drug Administration (FDA) is reassessing whether the 1999 heart health claim for soy protein should be revoked. Methods and Results We have, therefore, performed a cumulative meta-analysis on the 46 soy trials identified by the FDA to determine if at any time, since the 1999 FDA final rule that established the soy heart health claim, the soy effect on serum cholesterol lost significance. The cumulative meta-analysis for both total cholesterol and low-density lipoprotein cholesterol demonstrated preservation of the small, but significant, reductions seen both before and during the subsequent 14 years since the health claim was originally approved. For low-density lipoprotein cholesterol, the mean reduction in 1999 was -6.3 mg/dL (95% CI, -8.7 to -3.9 mg/dL; P=0.00001) and remained in the range of -4.2 to -6.7 mg/dL ( P=0.0006 to P=0.0002, respectively) in the years after 1999. At no time point did the total cholesterol or low-density lipoprotein cholesterol reductions lose significance or were the differences at individual time points in the cumulative meta-analysis significantly different from those seen in 1999 when the health claim was approved. Conclusions A cumulative meta-analysis of the data selected by the FDA indicates continued significance of total cholesterol and low-density lipoprotein cholesterol reduction after soy consumption and supports the rationale behind the original soy FDA heart health claim.
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Soy Protein Supplementation Reduces Clinical Indices in Type 2 Diabetes and Metabolic Syndrome.
Zhang, XM, Zhang, YB, Chi, MH
Yonsei medical journal. 2016;(3):681-9
Abstract
PURPOSE Clinical trials have studied the use of soy protein for treating type 2 diabetes (T2D) and metabolic syndrome (MS). The purpose of this study was to outline evidence on the effects of soy protein supplementation on clinical indices in T2D and MS subjects by performing a meta-analysis of randomized controlled trials (RCTs). MATERIALS AND METHODS We searched PubMed, EMBASE, and Cochrane databases up to March 2015 for RCTs. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model. A total of eleven studies with eleven clinical variables met the inclusion criteria. RESULTS The meta-analysis showed that fasting plasma glucose (FPG) [weighted mean difference (WMD), -0.207; 95% CI, -0.374 to -0.040; p=0.015], fasting serum insulin (FSI) (WMD, -0.292; 95% CI, -0.496 to -0.088; p=0.005), homeostasis model of assessment for insulin resistance index (HOMA-IR) (WMD, -0.346; 95% CI, -0.570 to -0.123; p=0.002), diastolic blood pressure (DBP) (WMD, -0.230; 95% CI, -0.441 to -0.019; p=0.033), low-density lipoprotein cholesterol (LDL-C) (WMD, -0.304; 95% CI, -0.461 to -0.148; p=0.000), total cholesterol (TC) (WMD, -0.386; 95% CI, -0.548 to -0.225; p=0.000), and C-reactive protein (CRP) (WMD, -0.510; 95% CI, -0.722 to -0.299; p=0.000) are significant reduced with soy protein supplementation, compared with a placebo control group, in T2D and MS patients. Furthermore, soy protein supplementation for longer duration (≥6 mo) significantly reduced FPG, LDL-C, and CRP, while that for a shorter duration (<6 mo) significantly reduced FSI and HOMA-IR. CONCLUSION Soy protein supplementation could be beneficial for FPG, FSI, HOMA-IR, DBP, LDL-C, TC, and CRP control in plasma.
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Do soy isoflavones improve cognitive function in postmenopausal women? A meta-analysis.
Cheng, PF, Chen, JJ, Zhou, XY, Ren, YF, Huang, W, Zhou, JJ, Xie, P
Menopause (New York, N.Y.). 2015;(2):198-206
Abstract
OBJECTIVE Several studies have demonstrated that soy isoflavone (SIF) supplementation can improve aspects of cognitive function. However, these findings remain controversial. We aimed to quantify the effects of SIF supplementation on improving cognitive function in postmenopausal women. METHODS Databases and relevant Websites were searched for relevant studies up to March 2014. Two reviewers independently verified all potentially suitable randomized controlled trials (RCTs) using inclusion and exclusion criteria, and the quality of identified RCTs was assessed using the Jadad scale and the Risk of Bias Tool from the "Cochrane handbook for systematic reviews of interventions." Any disagreement on study quality or data extraction was resolved by consensus; a third reviewer was consulted if needed. Standardized mean differences (SMDs) in cognitive function test scores were calculated between SIF-treated and placebo-treated groups. RESULTS We conducted a meta-analysis of 10 placebo-controlled RCTs of SIF supplementation (1,024 participants; treatment duration of 6 wk to 30 mo). The overall SMD in summary cognitive function test scores (0.08) was statistically significant (95% CI, 0.02-0.15; P = 0.014). The summary SMD for visual memory (0.10) was statistically significant (95% CI, 0.02-0.18; P = 0.016). In subgroup analyses, the statistically significant SMDs were as follows: 0.12 (95% CI, 0-0.25; P = 0.044) for non-US countries; 0.16 (95% CI, 0.05-0.28; P = 0.004) for mean age younger than 60 years; and 0.15 (95% CI, 0.03-0.27; P = 0.011) for treatment duration less than 12 months. CONCLUSIONS SIF supplementation seems to have a positive effect on improving summary cognitive function and visual memory in postmenopausal women. There may be a critical window of opportunity in initiating SIF use at an earlier age in postmenopausal women, and geography and treatment duration seem to be factors influencing the effects of SIF supplementation. All individuals in the included studies should be followed up to observe the incidence rates of Alzheimer's disease and dementia, and future studies should report any adverse effects of SIF supplementation.
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Association between soy isoflavone intake and breast cancer risk for pre- and post-menopausal women: a meta-analysis of epidemiological studies.
Chen, M, Rao, Y, Zheng, Y, Wei, S, Li, Y, Guo, T, Yin, P
PloS one. 2014;(2):e89288
Abstract
BACKGROUND Conclusions drawn from meta-analyses on the association between soy isoflavone intake and breast cancer risk for pre- and post-menopausal women are not fully consistent. These meta-analyses did not explore the influence of different study designs on the pooled results on the basis of distinguishing between pre- and post-menopausal women. METHODOLOGY AND PRINCIPAL FINDINGS We performed a meta-analysis of 35 studies which reported results of association between soy isoflavone intake and breast cancer risk for pre- and/or post-menopausal women, calculated pooled odds ratios and their 95% confidence intervals of pre- and post-menopausal women respectively, and further explored soy isoflavone-breast cancer association on the basis of considering different study regions and designs. Summary results suggested that soy isoflavone intake has a protective effect against breast cancer for both pre- and post-menopausal women. However, they are influenced by study design and region. Pooled ORs of studies carried out in Asian countries suggested that soy isoflavone's protective effect exist in both pre- and post-menopausal women (OR = 0.59, 95%CI: 0.48-0.69 for premenopausal women; OR = 0.59, 95%CI: 0.44-0.74 for postmenopausal women). However, there are some differences between the results pooled from different study designs for women in Asian countries (test for consistency, P = 0.04). Pooled OR of studies on postmenopausal women in Western countries suggested that soy isoflavone intake has a marginally significant protective effect (OR = 0.92; 95%CI: 0.83 ∼ 1.00), but further analyses stratifying by study design found no statistically significant association. CONCLUSIONS We meta-analyzed more and newer research results, and separated women according to menopausal status to explore soy isoflavone-breast cancer association. We founded that soy isoflavone intake could lower the risk of breast cancer for both pre- and post-menopausal women in Asian countries. However, for women in Western countries, pre- or post-menopausal, there is no evidence to suggest an association between intake of soy isoflavone and breast cancer.