***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Introduction Phytoestrogens are a group of compounds found in plants that structurally resemble the hormone oestradiol , and thus have the potential to act as oestrogen agonists or antagonists . Their potential effects may alter the risk of breast cancer , but only a limited range of phytoestrogens has been examined in prospect i ve cohort studies . Methods Serum and urine sample s from 237 incident breast cancer cases and 952 control individuals ( aged 45 to 75 years ) in the European Prospect i ve into Cancer-Norfolk cohort were analysed for seven phytoestrogens ( daidzein , enterodiol , enterolactone , genistein , glycitein , o-desmethylangolensin , and equol ) using liquid chromatography/mass spectrometry . Data on participants ' diet , demographics , anthropometrics , and medical history were collected upon recruitment . All models were adjusted for weight , fat and energy intake , family history of breast cancer , social class , analytical batch , and factors related to oestrogen exposure . Results Urinary or serum phytoestrogens were not associated with protection from breast cancer in the European Prospect i ve into Cancer-Norfolk cohort . Breast cancer risk was marginally increased with higher levels of total urinary isoflavones ( odds ratio = 1.08 ( 95 % confidence interval = 1.00 to 1.16 ) , P = 0.055 ) ; among those with oestrogen receptor-positive tumours , the risk of breast cancer was increased with higher levels of urinary equol ( odds ratio = 1.07 ( 95 % confidence interval = 1.01 to 1.12 ) , P = 0.013 ) . Conclusion There was limited evidence of an association between phytoestrogen biomarkers and breast cancer risk in the present study . There was no indication of decreased likelihood of breast cancer with higher levels of phytoestrogen biomarkers , but the observation that some phytoestrogen biomarkers may be associated with greater risk of breast cancer warrants further study with greater statistical power BACKGROUND Soy food is a rich source of isoflavones -- a class of phytoestrogens that has both antiestrogenic and anticarcinogenic properties . OBJECTIVE The objective was to evaluate the association of adolescent and adult soy food intake with breast cancer risk in a cohort of 73,223 Chinese women who participated in the Shanghai Women 's Health Study . DESIGN A vali date d food-frequency question naire was used to assess usual dietary intake during adulthood and adolescence . After a mean follow-up of 7.4 y , 592 incident cases of breast cancer were identified for longitudinal analyses by using Cox regressions . RESULTS Adult soy food consumption , measured either by soy protein or isoflavone intake , was inversely associated with the risk of premenopausal breast cancer , and the association was highly statistically significant ( P for trend < 0.001 ) . The multivariate-adjusted relative risks ( RRs ) for the upper intake quintile compared with the lowest quintile were 0.41 ( 95 % CI : 0.25 , 0.70 ) for soy protein intake and 0.44 ( 95 % CI : 0.26 , 0.73 ) for isoflavone intake . High intake of soy foods during adolescence was also associated with a reduced risk of premenopausal breast cancer ( RR : 0.57 ; 95 % CI : 0.34 , 0.97 ) . Women who consumed a high amount of soy foods consistently during adolescence and adulthood had a substantially reduced risk of breast cancer . No significant association with soy food consumption was found for postmenopausal breast cancer . CONCLUSION This large , population -based , prospect i ve cohort study provides strong evidence of a protective effect of soy food intake against premenopausal breast cancer Phytoestrogen intake may reduce breast cancer risk and limited evidence suggests this association may hold for hormone receptor‐positive tumors only . The study aims were to assess whether the association between phytoestrogen intake during adolescence and adulthood and breast cancer risk varies by estrogen and progesterone receptor ( ERPR ) tumor subgroup . Cases were identified from the Ontario Cancer Registry ( 2002–2003 ) , and ERPR status was ascertained from pathology reports for 81 % of cases ( n = 2,438 ) . Controls were identified through r and om digit dialing of Ontario households ( n = 3,370 ) . Published phytoestrogen food values were applied to food frequency question naire responses to assess isoflavone , lignan and total phytoestrogen intake , during adolescence and adulthood . Polytomous multivariate logistic regression was used to estimate adjusted odds ratios ( ORs ) for association between phytoestrogen intake and breast cancer risk by hormone receptor ERPR tumor subgroups . Among premenopausal women , few associations were observed for adolescent or adult phytoestrogen intake across all tumor subgroups . Among postmenopausal women , adolescent phytoestrogen intake ( isoflavone , lignan and total ) was associated with reduced risk across all hormone receptor subgroups ; however , statistical significance was most consistent within the ER+PR+ subgroup . For example , ER+PR+ postmenopausal breast cancer risk was associated with  adolescent phytoestrogen intake ( highest vs. lowest : OR = 0.79 ; 95 % confidence interval : 0.65–0.96 ) . Among all women and postmenopausal women , ORs for high adult lignan intake were all below 1.0 within each tumor subgroup , suggesting reduced breast cancer risk , although none reached statistical significance . In conclusion  , adolescent phytoestrogen intake was associated with reduced postmenopausal breast cancer , particularly for ER+PR+ tumor subgroup Controlled trials that use r and omized allocation are the best tool to control for bias and confounding in trials testing clinical interventions . Investigators must be sure to include information that is required by the reader to judge the validity and implication s of the findings in the reports of these trials . In part , complete reporting of trials will allow clinicians to modify their clinical practice to reflect current evidence toward the improvement of clinical outcomes . The consoli date d st and ards of reporting trials ( CONSORT ) statement was developed to assist investigators , authors , review ers , and editors on the necessary information to be included in reports of controlled clinical trials . The CONSORT statement is applicable to any intervention , including herbal medicinal products . Controlled trials of herbal interventions do not adequately report the information suggested in CONSORT . Recently , reporting recommendations were developed in which several CONSORT items were elaborated to become relevant and complete for r and omized controlled trials of herbal medicines . We expect that these recommendations will lead to more complete and accurate reporting of herbal trials . We wrote this explanatory document to outline the rationale for each recommendation and to assist authors in using them by providing the CONSORT items and the associated elaboration , together with examples of good reporting and empirical evidence , where available , for each . These recommendations for the reporting of herbal medicinal products presented here are open to revision as more evidence accumulates and critical comments are collected Results from epidemiological and experimental studies indicate that phytoestrogens may protect against  breast cancer .  Because one of the biological effects of phytoestrogens is probably estrogenic , it 's possible that the preventive effect on breast cancer differs by estrogen receptor ( ER ) or progesterone receptor ( PR ) status of the tumor . We evaluated the associations between dietary phytoestrogen ( isoflavonoids , lignans , and coumestrol ) intake and risk of breast cancer  and whether the ER/PR statuses of the tumor influence this relationship . In 1991 - 2 a prospect i ve population -based cohort study among Swedish pre- and postmenopausal women was performed , making question naire data available for 45,448 women . A total of 1014 invasive breast cancers were diagnosed until December 2004 . Cox proportional hazards models were performed to estimate multivariate risk ratios , 95 % CI for associations with risk of breast cancer . Intakes of lignan , isoflavonoid , or coumestrol were not associated with breast cancer risk overall or before or after 50 y of age . The effects of lignans or isoflavonoids were independent of receptor status . However , intake of coumestrol was associated with decreased risk of receptor negative tumors ( ER-PR- ) but not positive tumors . The risk of ER-PR- tumors was significantly lower ( 50 % ) in women with intermediate coumestrol intake compared with those who did not consume any . In conclusion , we found no association between intake of isoflavonoids or lignans and breast cancer risk . Our results of a decreased risk of ER-PR- tumors in women with intermediate intake of coumestrol could be due to chance because of the low intake . The results should be confirmed in other studies BACKGROUND A high intake of phytoestrogens , particularly isoflavones , has been suggested to decrease breast cancer risk . Results from human studies are inconclusive . OBJECTIVE We investigated the association between phytoestrogen intake and breast cancer risk in a large prospect i ve study in a Dutch population with a habitually low phytoestrogen intake . DESIGN The study population consisted of 15 555 women aged 49 - 70 y who constituted a Dutch cohort of the European Prospect i ve Investigation into Cancer and Nutriton ( EPIC ; 1993 - 1997 ) . Data concerning habitual dietary intake in the preceding year were obtained by using a vali date d food-frequency question naire . The content of isoflavones and lignans in relevant food items was estimated through a literature search , the use of food-composition tables , and contact with experts . Newly diagnosed breast cancer cases up to 1 January 2001 were identified through linkage with the Comprehensive Cancer Center Middle Netherl and s. Hazard ratios for the disease were estimated by Cox proportional hazard analysis for quartiles of isoflavone and lignan intake . Associations were adjusted for known breast cancer risk factors and daily energy intake . RESULTS A total of 280 women were newly diagnosed with breast cancer during follow-up . The median daily intakes of isoflavones and lignans were 0.4 ( interquartile range : 0.3 - 0.5 ) and 0.7 ( 0.5 - 0.8 ) mg/d , respectively . Relative to the respective lowest intake quartiles , the hazard ratios for the highest intake quartiles for isoflavones and lignans were 1.0 ( 95 % CI : 0.7 , 1.5 ) and 0.7 ( 0.5 , 1.1 ) , respectively . Tests for trend were nonsignificant . CONCLUSION In Western population s , a high intake of isoflavones or mammalian lignans is not significantly related to breast cancer risk Soy consumption may be related to lower  breast cancer  risk as assessed by breast density . The aims of this 2-y trial were to examine the effects of soy foods and lifetime soy intake on mammographic density . After 220 premenopausal women were r and omly assigned to the intervention or control group , the former group consumed 2 daily servings of soy foods equivalent to 50 mg of isoflavones and the latter consumed their regular diet . The respective dropout rates were 15.6 and 12.6 % ; adherence to the study regimen was high . We assessed lifetime soy intake with a question naire and measured breast density in screening mammograms obtained at baseline and at the end of the trial for 98 intervention and 103 control women using a computer-assisted method . None of the mammographic outcomes differed significantly by experimental group . The total area of the breast increased and the size of the dense areas decreased significantly over time in both groups . After 2 y , the mean percentage density had decreased by 2.8 and 4.1 % in intervention and control women , respectively . Women who reported eating more soy during their lives had higher percentage densities than women whose diet included little soy ; this difference was significant only in Caucasians . Lower  soy  intake during early life and higher soy intake during adulthood predicted a greater reduction in the percentage density during the study period . After 2 y of intervention , we observed no significant differences in mammographic densities by intervention status , but it appears that soy consumption throughout life may have some effect on breast density Some epidemiologic studies reported an association between a low ratio of urinary 2-hydroxyestrogens ( 2-hydroxyestradiol + 2-hydroxyestrone ) to 16alpha-hydroxyestrone ( 2:16OHE(1 ) ) and increased  breast cancer risk . Some studies show that soy consumption increases this ratio , and it is suggested that this effect may reduce breast cancer risk . We hypothesized that consumption of probiotic bacteria would alter fecal bacteria and enzymes involved in soy isoflavone metabolism , thereby increasing isoflavone bioavailability and enhancing the beneficial effects of soy on estrogen metabolism .  Breast cancer survivors ( n = 20 ) and controls ( n = 20 ) were given 4 treatments for 6 wk each , separated by 2-wk washout periods , in a r and omized , crossover design : soy protein ( 26.6 + /- 4.5 g protein/d containing 44.4 + /- 7.5 mg isoflavones/d ) ; soy protein + probiotics ( 10(9 ) colony-forming units Lactobacillus acidophilus DDS(R)+1 & Bifidobacterium longum , 15 - 30 mg fructooligosaccharide/d ) ; milk protein ( 26.6 + / 
    Output:
    
There is lack of evidence showing harm from use of soy with respect to risk of breast cancer or recurrence , based on long term observational data .
Soy intake consistent with that of a traditional Japanese diet ( 2 - 3 servings daily , containing 25 - 50 mg isoflavones ) may be protective against breast cancer and recurrence .
Human trials show that soy does not increase circulating estradiol or affect estrogen-responsive target tissues .
Prospect i ve data of soy use in women taking tamoxifen does not indicate increased risk of recurrence .
Evidence on red clover is limited , however existing studies suggest that it may not possess breast cancer-promoting effects .
Conclusion Soy consumption may be associated with reduced risk of breast cancer incidence , recurrence , and mortality .
Soy does not have estrogenic effects in humans .
Soy intake consistent with a traditional Japanese diet appears safe for breast cancer survivors .
While there is no clear evidence of harm , better evidence confirming safety is required before use of high dose ( ≥100 mg ) isoflavones can be recommended for breast cancer patients