A 2-year soy intervention in premenopausal women does not change mammographic densities

A Randomized Controlled Trial of Soy Isoflavone Intake on Mammographic Density among Malaysian Women

Soy intake is associated with lower breast cancer risk in observational studies concerning Asian women, however, no randomized controlled trials (RCT) have been conducted among Asian women living in Asia. This three-armed RCT assessed the effects of one-year soy isoflavone (ISF) intervention on mammographic density (MD) change among healthy peri- and postmenopausal Malaysian women. This study was registered at ClinicalTrials.gov (NCT03686098). Participants were randomized into the 100 mg/day ISF Supplement, 50 mg/day ISF Diet, or control arm, and assessed for change in absolute and relative dense area from digital mammograms conducted at enrolment and after 12 months, compared over time across study arms using Kruskal-Wallis tests. Out of 118 women enrolled, 91 women completed the intervention, while 27 women (23%) were lost in follow up. The ISF supplement arm participants observed a larger decline in dense area (−1.3 cm2), compared to the ISF diet (−0.5 cm2) and control arm (−0.8 cm2), though it was not statistically significant (p = 0.48). Notably, among women enrolled within 5 years of menopause; dense area declined by 6 cm2 in the ISF supplement arm, compared to <1.0 cm2 in the control arm (p = 0.13). This RCT demonstrates a possible causal association between soy ISF intake and MD, a biomarker of breast cancer risk, among Asian women around the time of menopause, but these findings require confirmation in a larger trial.

Habitual Phytoestrogen Intake Is Associated with Breast Composition in Girls at 2 Years after Menarche Onset

BACKGROUND

High phytoestrogen intake during adolescence is associated with a reduced risk of breast cancer. Breast density (BD) is a strong predictor of breast cancer and can be considered an early marker. We aim to assess the association between the mean habitual intake of isoflavones, lignans, and total phytoestrogens intake during puberty until 2 years after menarche onset and absolute fibroglandular volume (AFGV) and percentage of fibroglandular volume (%FGV) in Hispanic girls at the end of puberty.

METHODS

Longitudinal study set up in the Growth and Obesity Chilean Cohort Study (GOCS). We included 329 girls with dietary data (multiple 24-hours recalls) from puberty until 2 years after menarche onset (81% had 2-4 recalls). Two international datasets were used to estimate isoflavones, lignans, and total phytoestrogens in the diet. Breast composition was measured by dual energy X-ray absorptiometry at 2 years after menarche. Multiple linear regression models were used to assess the association between isoflavones, lignans, and total phytoestrogens intake and AFGV and %FGV.

RESULTS

The average total phytoestrogen intake was 1 mg/day and %FGV was 50.7% (SD = 15.2) and AFGV 218.8 cm3 (SD = 79.3). An inverse association was found between consumption of isoflavones and AFGV, as well as, with total phytoestrogens [Q4 vs. Q1 adjusted model ß = -49.2 cm3; 95% CI (-85.5 to -13.0)].

CONCLUSIONS

Girls with a higher intake of total phytoestrogens and isoflavones during puberty until 2 years after menarche onset had significantly lower AFGV.

IMPACT

Although the intake of phytoestrogens is low in Western populations, higher consumption of them during a critical period of life like puberty could be beneficial to reduce breast cancer during adulthood.

Genistein, a Potential Phytochemical against Breast Cancer Treatment-Insight into the Molecular Mechanisms

Breast cancer (BC) is one of the most common malignancies in women. Although widespread successful synthetic drugs are available, natural compounds can also be considered as significant anticancer agents for treating BC. Some natural compounds have similar effects as synthetic drugs with fewer side effects on normal cells. Therefore, we aimed to unravel and analyze several molecular mechanisms of genistein (GNT) against BC. GNT is a type of dietary phytoestrogen included in the flavonoid group with a similar structure to estrogen that might provide a strong alternative and complementary medicine to existing chemotherapeutic drugs. Previous research reported that GNT could target the estrogen receptor (ER) human epidermal growth factor receptor-2 (HER2) and several signaling molecules against multiple BC cell lines and sensitize cancer cell lines to this compound when used at an optimal inhibitory concentration. More specifically, GNT mediates the anticancer mechanism through apoptosis induction, arresting the cell cycle, inhibiting angiogenesis and metastasis, mammosphere formation, and targeting and suppressing tumor growth factors. Furthermore, it acts via upregulating tumor suppressor genes and downregulating oncogenes in vitro and animal model studies. In addition, this phytochemical synergistically reverses the resistance mechanism of standard chemotherapeutic drugs, increasing their efficacy against BC. Overall, in this review, we discuss several molecular interactions of GNT with numerous cellular targets in the BC model and show its anticancer activities alone and synergistically. We conclude that GNT can have favorable therapeutic advantages when standard drugs are not available in the pharma markets.

Impact of 18-Month Soy Protein Supplementation on Steroid Hormones and Serum Biomarkers of Angiogenesis, Apoptosis, and the Growth Hormone/IGF-1 Axis: Results of a Randomized, Placebo-Controlled Trial in Males Following Prostatectomy

Many studies have addressed the effects of dietary supplementation with soy protein on cancer risk and mortality, but there are only few randomized studies with soy in males. We used serum samples from a two-year trial of soy protein isolate supplementation in middle-aged to older males at risk of recurrence of prostate cancer after radical prostatectomy to determine soy effects on steroid hormones involved in prostate cancer (testosterone, SHBG, and estradiol) and explore the effects on biomarkers of the growth hormone/IGF-1 axis, apoptosis, and angiogenesis. Compared with a casein-based placebo, 18 mo, of consumption of 19.2 g/day of whole soy protein isolate containing 24 mg genistein-reduced circulating testosterone and SHBG, but not free testosterone, and did not affect serum concentrations of estradiol, VEGF, IGF-1, IGFBP-3, IGF-1/IGFBP-3 ratio, soluble Fas, Fas-ligand, and sFas/Fas-ligand ratio. Thus, soy protein supplementation for 18 mo, affected the androgen axis, but the effects on other cancer biomarkers remain to be more definitively determined. The study was registered at clinicaltrials.gov (NCT00765479).

The Potential of Natural Products in the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer that lacks receptors for targeted therapy. Consequently, chemotherapy is currently the mainstay of systemic treatment options. However, the enrichment of cancer stem cells (CSC, a subpopulation with stem-cell characteristics and tumor-initiating propensity) promotes chemo-resistance and tumorigenesis, resulting in cancer recurrence and relapse. Furthermore, toxic side effects of chemotherapeutics reduce patient wellbeing. Natural products, specifically compounds derived from plants, have the potential to treat TNBC and target CSCs by inhibiting CSC signaling pathways. Literature evidence from six promising compounds were reviewed, including sulforaphane, curcumin, genistein, resveratrol, lycopene, and epigallocatechin-3-gallate. These compounds have been shown to promote cell cycle arrest and apoptosis in TNBC cells. They also could inhibit the epithelial-mesenchymal transition (EMT) that plays an important role in metastasis. In addition, those natural compounds have been found to inhibit pathways important for CSCs, such as NF-κB, PI3K/Akt/mTOR, Notch 1, Wnt/β-catenin, and YAP. Clinicals trials conducted on these compounds have shown varying degrees of effectiveness. Epidemiological case-control studies for the compounds commonly consumed in certain human populations have also been summarized. While in vivo and in vitro data are promising, further basic and clinical investigations are required. Likely, natural products in combination with other drugs may hold great potential to improve TNBC treatment efficacy and patient outcomes.

Effect of the Intake of Isoflavones on Risk Factors of Breast Cancer-A Systematic Review of Randomized Controlled Intervention Studies

Epidemiological studies suggest that high intake of soy isoflavones may protect against breast cancer, but causal relationships can only be established by experimental trials. Thus, we aimed to provide a systematic review of randomized controlled trials (RCTs) on the effect of an isoflavone intake on risk factors of breast cancer in healthy subjects. After a systematic literature search in PubMed, 18 different RCTs with pre- and/or postmenopausal women were included and investigated for details according to the PRISMA guideline. In these studies, isoflavones were provided by soy food or supplements in amounts between 36.5-235 mg/d for a period of 1-36 months. Breast density, estrogens including precursors, metabolites, estrogen response such as length of menstrual cycle, and markers of proliferation and inflammation were considered. However, in most studies, differences were not detectable between isoflavone and control/placebo treatment despite a good adherence to isoflavone treatment, irrespective of the kind of intervention, the dose of isoflavones used, and the duration of isoflavone treatment. However, the lack of significant changes in most studies does not prove the lack of effects as a sample size calculation was often missing. Taking into account the risk of bias and methodological limitations, there is little evidence that isoflavone treatment modulates risk factors of breast cancer in pre- and postmenopausal women. Future studies should calculate the sample size to detect possible effects and consider methodological details to improve the study quality.

The Protective Effect of Echinochrome A on Extracellular Matrix of Vocal Folds in Ovariectomized Rats

Here, we investigated the effects of sex hormones on extracellular matrix (ECM)-related gene expression in the vocal fold lamina propria of ovariectomized (after ovary removal) rats and verified whether echinochrome A (ECH) exerts any therapeutic effects on ECM reconstitution after estrogen deficiency in ovariectomized rats. Sprague–Dawley female rats (9 weeks old) were acclimatized for a week and randomly divided into three groups (n = 15 each group) as follows: group I (sham-operated rats, SHAM), group II (ovariectomized rats, OVX), group III (ovariectomized rats treated with ECH, OVX + ECH). Rats from the OVX + ECH group were intraperitoneally injected with ECH at 10 mg/kg thrice a week after surgery for 6 weeks. And rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in OVX group compared with the SHAM group. ECH treatment had no effect on the levels of estradiol and expression of estrogen receptor β (ERβ). The evaluation of ECM components showed no significant changes in elastin and hyaluronic acid levels between the different groups. Collagen I and III levels were lower in OVX group than in SHAM group but increased in OVX + ECH group. The mRNA levels of matrix metalloproteinase (MMP)-1, -2, -8, and -9 were significantly higher in the OVX group than in the SHAM group, but decreased in the OVX + ECH group. Thus, changes were observed in ECM-related genes in the OVX group upon estradiol deficiency that were ameliorated by ECH administration. Thus, the vocal fold is an estradiol-sensitive target organ and ECH may have protective effects on the ECM of vocal folds in ovariectomized rats.

Milk intake and mammographic density in premenopausal women

PURPOSE

Mammographic density is a strong risk factor for breast cancer. Although diet is associated with breast cancer risk, there are limited studies linking adult diet, including milk intake, with mammographic density. Here, we investigate the association of milk intake with mammographic density in premenopausal women.

METHODS

We analyzed data from 375 cancer-free premenopausal women who had routine screening mammography at Washington University School of Medicine, St. Louis, Missouri in 2016. We used Volpara to measure volumetric percent density, dense volume, and non-dense volume. We collected information on recent milk intake (past 12 months), and categorized skim milk and low/reduced-fat milk intake into 4 groups: < 1/week, 1/week, 2-6 times/week, ≥ 1/day, while whole and soy milk intake were categorized into 2 groups: < 1/week, ≥ 1/week. We used multivariable linear regression model to evaluate the associations of milk intake and log-transformed volumetric percent density, dense volume, and non-dense volume.

RESULTS

In multivariable analyses, volumetric percent density was 20% (p-value = 0.003) lower in the 1/week group, 14% (p-value = 0.047) lower in the 2-6/week group, and 12% (p-value = 0.144) lower in the ≥ 1/day group (p-trend = 0.011) compared with women who consumed low/reduced-fat milk < 1/week. Attenuated and non-significant associations were observed for low/reduced-fat milk intake and dense volume. There were no associations of whole, skim, and soy milk intake with volumetric percent density and dense volume.

CONCLUSIONS

Recent low/reduced-fat milk intake was inversely associated with volumetric percent density in premenopausal women. Studies on childhood and adolescent milk intake and adult mammographic density in premenopausal women are needed.

Use of hormone therapy and isoflavones and mammographic density in Spain

OBJECTIVE

The use of some forms of hormone therapy (HT) is associated with an increase in mammographic density-a major risk factor for breast cancer. The role of isoflavones, however, is unclear. Here, we quantify the prevalence of HT and isoflavone use among postmenopausal Spanish women, determine associated risk factors, and explore the relationship between these therapies and mammographic density.

METHODS

This cross-sectional study included 2,754 postmenopausal women who underwent breast cancer screening in seven geographical areas. Mammographic density was evaluated using Boyd's semiquantitative scale. Multinomial logistic regression models were adjusted to assess risk factors associated with both therapies. Ordinal regression models were fitted to study the association between HT and isoflavone consumption with mammographic density.

RESULTS

The prevalence of ever-use of HT was 12%, whereas that of the current use was 2.3%. Isoflavone lifetime prevalence was 3.7%, and current use was 1.7%. The most common HT types were tibolone and estrogens. Surgical menopause, oral contraceptive use, educational level, population density, and years since menopause were positively associated with HT, whereas body mass index and parity were inversely associated. Mammographic density was not associated with current or past HT use. However, women who reported having consumed isoflavones in the past and those who started their use after menopause had a higher mammographic density when compared with never-users (odds ratio 1.98, 95% CI 1.21-3.25, P = 0.007; and odds ratio 1.60, 95% CI 1.01-2.53, P = 0.045 respectively).

CONCLUSIONS

Our results show a low prevalence of HT and isoflavone use in postmenopausal Spanish women. In this population, HT use was not associated with mammographic density, whereas some categories of isoflavone users had higher density.

Effect of Soy and Soy Isoflavones on Obesity-Related Anthropometric Measures: A Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials

Soy may be a suitable food for anti-obesity efforts because of its high protein and isoflavone content. We conducted this meta-analysis to evaluate potential effects of soy and soy isoflavones on weight, waist circumference, and fat mass. PubMed, MEDLINE, Scopus, EMBASE, and Cochrane databases were searched. Twenty-four trials with soy and 17 trials with isoflavones passed the eligibility stage. According to the results, soy showed no overall statistically significant effect on weight, waist circumference, or fat mass, but a significant increasing effect on weight was observed in some circumstances: for instance, in obese subjects [mean difference (MD): 0.80 kg; 95% CI: 0.15, 1.45 kg; P = 0.02], with ingestions of ≥40 g soy protein/d (MD: 0.94 kg; 95% CI: 0.11, 1.77 kg; P = 0.03), with short-term applications (1-3 mo) (MD: 0.45 kg; 95% CI: 0.05, 0.86 kg; P = 0.03), and when soy was compared with meat (MD: 0.36 kg; 95% CI: 0.09, 0.64 kg; P = 0.03) and whey protein (MD: 1.53 kg; 95% CI: 0.10, 2.96 kg; P = 0.04). In contrast to the effects of soy on weight, soy significantly decreased waist circumference in older ages (MD: -0.36 cm; 95% CI: -0.71, -0.01 cm; P = 0.04), in women (MD: -0.32 cm; 95% CI: -0.57, -0.08 cm; P = 0.01), and at doses of <40 g soy protein/d (MD: -0.31 cm; 95% CI: -0.57, -0.05 cm; P = 0.02). Isoflavone studies, conducted only in women, showed that isoflavones may reduce body mass index (BMI; in kg/m2) (MD: -0.26; 95% CI: -0.55, 0.04; P = 0.085), especially in dosages <100 mg/d (MD: -0.48; 95% CI: -0.90, -0.06; P = 0.02) and in intervention periods of 2-6 mo (MD: -0.28; 95% CI: -0.56, 0.00; P = 0.053), but no effect was observed in higher doses or longer intervention periods. Also, a trend for reduced BMI after consumption of isoflavones was observed in Caucasians (MD: -0.35; 95% CI: -0.74, 0.04; P = 0.08). Overall, results showed that, although soy is the major source of isoflavones, soy and isoflavones may have different impacts on weight status.

Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women?

Soy foods may protect against breast cancer in Asian but not in Western populations. We examined if the levels of various markers of breast cancer risk and inflammation, as well as the effects of soy food consumption on these markers, differ between Asian and non-Asian premenopausal women in two soy intervention trials. One study randomized 220 women to a 2-yr intervention and the other one randomized 96 women in a crossover design to examine the effects of consumption of 2 daily soy servings on nipple aspirate fluid (NAF) volume; estrogens in serum, NAF, and urine; insulin-like growth factor-1 (IGF-1), IGF-binding protein 3, and inflammatory markers in serum; and mammographic densities. Mixed linear models were applied to assess ethnic differences in biomarkers and response to the soy diet. Serum C-reactive protein, serum leptin, NAF volume, and NAF estrone sulfate were lower, while urinary isoflavones were higher in Asian than in non-Asian women. A significant interaction (p_interaction = 0.05) between ethnicity and soy diet was observed for IGF-1 but not for other biomarkers. The current findings suggest possible ethnic differences in levels of biomarkers for breast cancer risk but little evidence that Asian women respond differently to soy foods than non-Asian women.

Aglycone rich extracts of phytoestrogens cause ROS-mediated DNA damage in breast carcinoma cells

Phytoestrogens are known for their physiological role in lowering risk of osteoporosis, heart disease, breast cancer and menopausal symptoms. They are plant derived potent anti-oxidants, but tend to show pro-oxidant effect at higher concentrations. This study has been undertaken to exploit their pro-oxidant effect in the management of cancer. Cancer cells inherently possess high intracellular ROS levels, however, these levels do not cause harm to the cancer cells because of the anti-oxidant enzyme system. So, there is a need for a treatment strategy which could modulate the ROS levels. Breast cancer cell lines MCF-7 and MDA-MB-231 are treated with various concentrations of soyabean aglycone rich extracts (SARE) and flaxseed aglycone rich extracts (FSARE). The treatment brings about a significant decrease in super oxide dismutase (SOD) and glutathione peroxidase (GPx) activity, thereby leading to accumulation of superoxide ion and peroxide in the cells. The catalase (CAT) activity however, did not show a dose dependent change. The intra-cellular reactive oxygen species (ROS) levels increased and a marked change in mitochondrial membrane potential was detected. Cell cycle arrest was seen at S and G2/M phase in MCF-7 cells and high accumulation of cells in Sub G1 phase was seen in MDA-MB-231 cells. Microscopic evaluation indicated apoptotic morphology and DNA damage. This study suggests an important role of soyabean and flaxseed aglycones in modulating intracellular ROS in breast carcinoma.

Relationship Between Breast Density and Selective Estrogen-Receptor Modulators, Aromatase Inhibitors, Physical Activity, and Diet: A Systematic Review

Background Lower breast density (BD) is associated with lower risk of breast cancer and may serve as a biomarker for the efficacy of chemopreventive strategies. This review explores parameters that are thought to be associated with lower BD. We conducted a systematic review of articles published to date using the PRISMA strategy. Articles that assessed change in BD with estrogen-receptor modulators (tamoxifene [TAM], raloxifene [RLX], and tibolone) and aromatase inhibitors (AIs), as well as cross-sectional and longitudinal studies (LSs) that assessed association between BD and physical activity (PA) or diet were reviewed. Results Ten studies assessed change in BD with TAM; all reported TAM-mediated BD decreases. Change in BD with RLX was assessed by 11 studies; 3 reported a reduction in BD. Effect of tibolone was assessed by 5 RCTs; only 1 reported change in BD. AI-mediated BD reduction was reported by 3 out of 10 studies. The association between PA and BD was assessed by 21 studies; 4 reported an inverse association. The relationship between diet and BD was assessed in 34 studies. All studies on calcium and vitamin D as well as vegetable intake reported an inverse association with BD in premenopausal women. Two RCTs demonstrated BD reduction with a low-fat, high-carbohydrate intervention. Conclusion TAM induces BD reduction; however, the effect of RLX, tibolone, and AIs on BD is unclear. Although data on association between diet and BD in adulthood are contradictory, intake of vegetables, vitamin D, and calcium appear to be associated with lower BD in premenopausal women.

European medicinal and edible plants associated with subacute and chronic toxicity part I: Plants with carcinogenic, teratogenic and endocrine-disrupting effects

In recent decades, the use of herbal medicines and food products has been widely embraced in many developed countries. These products are generally highly accepted by consumers who often believe that "natural" equals "safe". This is, however, an oversimplification because several botanicals have been found to contain toxic compounds in concentrations harmful to human health. Acutely toxic plants are in most cases already recognised as dangerous as a result of their traditional use, but plants with subacute and chronic toxicity are difficult or even impossible to detect by traditional use or by clinical research studies. In this review, we systematically address major issues including the carcinogenicity, teratogenicity and endocrine-disrupting effects associated with the use of herbal preparations with a strong focus on plant species that either grow natively or are cultivated in Europe. The basic information regarding the molecular mechanisms of the individual subtypes of plant-induced non-acute toxicity is given, which is followed by a discussion of the pathophysiological and clinical characteristics. We describe the genotoxic and carcinogenic effects of alkenylbenzenes, pyrrolizidine alkaloids and bracken fern ptaquiloside, the teratogenicity issues regarding anthraquinone glycosides and specific alkaloids, and discuss the human health concerns regarding the phytoestrogens and licorice consumption in detail.

Chemoprevention of Breast Cancer by Dietary Polyphenols

The review will discuss in detail the effects of polyphenols on breast cancer, including both the advantages and disadvantages of the applications of these natural compounds. First, we focus on the characterization of the main classes of polyphenols and then on in vitro and in vivo experiments carried out in breast cancer models. Since the therapeutic effects of the administration of a single type of polyphenol might be limited because of the reduced bioavailability of these drugs, investigations on combination of several polyphenols or polyphenols with conventional therapy will also be discussed. In addition, we present recent data focusing on clinical trials with polyphenols and new approaches with nanoparticles in breast cancer. Besides the clinical and translational findings this review systematically summarizes our current knowledge about the molecular mechanisms of anti-cancer effects of polyphenols, which are related to apoptosis, cell cycle regulation, plasma membrane receptors, signaling pathways and epigenetic mechanisms. At the same time the effects of polyphenols on primary tumor, metastasis and angiogenesis in breast cancer are discussed. The increasing enthusiasm regarding the combination of polyphenols and conventional therapy in breast cancer might lead to additional efforts to motivate further research in this field.

Double-Blind Randomized 12-Month Soy Intervention Had No Effects on Breast MRI Fibroglandular Tissue Density or Mammographic Density

Soy supplementation by patients with breast cancer remains controversial. No controlled intervention studies have investigated the effects of soy supplementation on mammographic density in patients with breast cancer. We conducted a double-blind, randomized, placebo-controlled intervention study in previously treated patients with breast cancer (n = 66) and high-risk women (n = 29). We obtained digital mammograms and breast MRI scans at baseline and after 12 months of daily soy (50 mg isoflavones per day; n = 46) or placebo (n = 49) tablet supplementation. The total breast area (MA) and the area of mammographic density (MD) on the mammogram were measured using a validated computer-assisted method, and mammographic density percent (MD% = 100 × MD/MA) was determined. A well-tested computer algorithm was used to quantitatively measure the total breast volume (TBV) and fibroglandular tissue volume (FGV) on the breast MRI, and the FGV percent (FGV% = 100 × FGV/TBV) was calculated. On the basis of plasma soy isoflavone levels, compliance was excellent. Small decreases in MD% measured by the ratios of month 12 to baseline levels were seen in the soy (0.95) and the placebo (0.87) groups; these changes did not differ between the treatments (P = 0.38). Small decreases in FGV% were also found in both the soy (0.90) and the placebo (0.92) groups; these changes also did not differ between the treatments (P = 0.48). Results were comparable in patients with breast cancer and high-risk women. We found no evidence that soy supplementation would decrease mammographic density and that MRI might be more sensitive to changes in density than mammography.

Association between high-sensitivity C-reactive protein (hsCRP) and change in mammographic density over time in the SWAN mammographic density subcohort

PURPOSE

High mammographic density (MD) is a strong risk factor for breast cancer. Chronic inflammation may be related to breast cancer risk through a mechanism involving the percent of breast area that is dense (percent MD). Longitudinal assessments, however, are lacking and thus were constructed to evaluate the relationship between chronic inflammation and percent MD.

METHODS

We evaluated whether elevated (>3 mg/L) high-sensitivity C-reactive protein (hsCRP), a biomarker of inflammation, was associated with change in percent MD among 653 women aged 42-52 years at baseline in the Study of Women's Health Across the Nation, a longitudinal study of midlife women. We used a mixed model to analyze data from an average of 4.7 mammograms per woman collected during an average follow-up of 4.9 years (SD = 1.47).

RESULTS

Elevated hsCRP at baseline was associated with lower baseline percent MD and a significantly slower annual decline over time of percent MD in an adjusted model that did not include body mass index (BMI) (β = 0.88, 95 % CI 0.44, 1.31). This association was attenuated and nonsignificant when BMI was included in the model (β = 0.37, 95 % CI -0.09, 0.84). Elevated hsCRP levels over time (time-varying elevated hsCRP levels) were also associated with a significantly slower decline in percent MD (β = 0.62, 95 % CI 0.30, 0.94). This association was attenuated, but still significant after adjusting for baseline BMI (β = 0.40, 95 % CI 0.07, 0.73).

CONCLUSION

These results suggest that inflammation may be related to slower reduction in percent MD.

Serum coenzyme Q₁₀, α-tocopherol, γ-tocopherol, and C-reactive protein levels and body mass index in adolescent and premenopausal females

OBJECTIVE

Lipid-soluble antioxidants are associated with a lower incidence for many chronic diseases of aging, possibly by preventing damage from chronic inflammation. In the current study, we compared serum levels of coenzyme Q₁₀ (CoQ₁₀), α-tocopherol, γ-tocopherol, and C-reactive protein (CRP) between adolescent girls and premenopausal women to assess changes from childhood to midlife.

METHODS

Baseline serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels were measured in 207 girls (13-19 years) and 183 premenopausal women (34-47 years) using standard methods and the 2 age groups were compared by t test. The influence of age, body mass index (BMI), and race/ethnicity and interaction effects on serum values were assessed using analysis of covariance. Pearson correlation coefficients were used to assess associations between pairs of lipid micronutrients.

RESULTS

Overall, adolescent girls had significantly lower mean serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels relative to premenopausal women (CoQ10: 376 vs 544 ng/mL, p < 0.0001; α-tocopherol: 6.9 vs 13.5 μg/mL, p < 0.0001; γ-tocopherol: 1.3 vs 1.7 μg/mL, p < 0.0001; CRP: 1.29 vs 2.13 mg/L, p < 0.0001). The differences in CoQ₁₀ and tocopherols remained significant after adjustment for BMI and race/ethnicity. CoQ₁₀ was significantly and positively correlated to α- and γ-tocopherol, and BMI was positively associated with CRP and γ-tocopherol in both groups.

CONCLUSIONS

Lower serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels in adolescent girls compared to women suggests that adolescents may have a reduced need for antioxidants possibly due to their lower BMI and inflammatory status as indicated by CRP.

Soy, red clover, and isoflavones and breast cancer: a systematic review

BACKGROUND

Soy and red clover isoflavones are controversial due to purported estrogenic activity and possible effects on breast cancer. We conducted a systematic review of soy and red clover for efficacy in improving menopausal symptoms in women with breast cancer, and for potential impact on risk of breast cancer incidence or recurrence.

METHODS

We searched MEDLINE, Embase, the Cochrane Library, and AMED from inception to March 2013 for human interventional or observational data pertaining to the safety and efficacy of soy and red clover isoflavones in patients with or at risk of breast cancer.

RESULTS

Of 4179 records, we included a total of 131 articles: 40 RCTs, 11 uncontrolled trials, and 80 observational studies. Five RCTs reported on the efficacy of soy for hot flashes, showing no significant reductions in hot flashes compared to placebo. 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 25-50mg 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. Prospective 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.

Cytology in nipple aspirate fluid during a randomized soy food intervention among premenopausal women

Because soy food consumption may influence breast tissue activity, we examined its effect on the presence of epithelial cells in nipple aspirate fluid (NAF). In a randomized, crossover design, 82 premenopausal women completed a high-soy and a low-soy diet for 6 mo each, separated by a 1-mo washout period. They provided NAF samples at baseline, 6 mo, and 13 mo during the midluteal phase of the menstrual cycle. Papanicolaou-stained cytology slides (for 33 women at baseline, 24 at low-soy, and 36 at high-soy) were evaluated in women with sufficient NAF. Mixed models evaluated the effect of the high-soy diet on epithelial cytology as compared to baseline and the low-soy diet. At the end of the high-soy diet, cytological subclass had decreased in 8 (24%) and increased in 3 (9%) women as compared to baseline, whereas the respective values were 3 (14%) and 6 (29%) for the low-soy diet samples (P = 0.32). Only the change in subclass indicated a trend in lower cytological class (P = 0.06). Contrary to an earlier report, the number of NAF samples with hyperplastic epithelial cells did not increase after a soy intervention in amounts consumed by Asians.

Flavonoids and cancer prevention: a review of the evidence

The objective of this work is to review data from epidemiological and preclinical studies addressing the potential benefits of diets based on flavonoids for cancer prevention. Flavonoids are subdivided into subclasses including flavonols, flavones, flavanones, flavan-3-ols, anthocyanidins, and isoflavones. Epidemiological studies suggest dietary intake of flavonoids may reduce the risk of tumors of the breast, colon, lung, prostate, and pancreas. However, some studies have reported inconclusive or even harmful associations. A major challenge in the interpretation of epidemiological studies is that most of the data originate from case-control studies and retrospective acquisition of flavonoid intake. Differences in agricultural, sociodemographics, and lifestyle factors contribute to the heterogeneity in the intake of flavonoids among populations residing in the United States, Europe, and Asia. Dose and timing of exposure may influence the anticancer response to flavonoid-rich diets. A limited number of intervention trials of flavonoids have documented cancer preventative effects. Proposed anticancer mechanisms for flavonoids are inhibition of proliferation, inflammation, invasion, metastasis, and activation of apoptosis. Prospective studies with larger sample sizes are needed to develop biomarkers of flavonoid intake and effect. Mechanistic studies are needed to ascertain how flavonoid-rich diets influence gene regulation for cancer prevention.

Redefining the impact of nutrition on breast cancer incidence: is epigenetics involved?

Breast cancer incidence is rising worldwide with an increase in aggressive neoplasias in young women. Possible factors involved include lifestyle changes, notably diet that is known to make an impact on gene transcription. However, among dietary factors, there is sufficient support for only greater body weight and alcohol consumption whereas numerous studies revealing an impact of specific diets and nutrients on breast cancer risk show conflicting results. Also, little information is available from middle- and low-income countries. The diversity of gene expression profiles found in breast cancers indicates that transcription control is critical for the outcome of the disease. This suggests the need for studies on nutrients that affect epigenetic mechanisms of transcription, such as DNA methylation and post-translational modifications of histones. In the present review, a new examination of the relationship between diet and breast cancer based on transcription control is proposed in light of epidemiological, animal and clinical studies. The mechanisms underlying the impact of diets on breast cancer development and factors that impede reaching clear conclusions are discussed. Understanding the interaction between nutrition and epigenetics (gene expression control via chromatin structure) is critical in light of the influence of diet during early stages of mammary gland development on breast cancer risk, suggesting a persistent effect on gene expression as shown by the influence of certain nutrients on DNA methylation. Successful development of breast cancer prevention strategies will require appropriate models, identification of biological markers for rapid assessment of preventive interventions, and coordinated worldwide research to discern the effects of diet.

Interaction effects between genes involved in the AKT signaling pathway and phytoestrogens in gastric carcinogenesis: a nested case-control study from the Korean Multi-Center Cancer Cohort

SCOPE

To investigate whether genes involved in AKT/nuclear factor kappa B signaling and/or gene-environment interactions between the genes and phytoestrogens may be susceptible factors for gastric cancer.

METHODS AND RESULTS

The representative single nucleotide polymorphisms (SNPs) identified during the primary analysis (screening a total of 622 SNPs within ± 5 kbp of the 51 target gene locations) were further investigated in 317 matched case-control sets. The summary odds ratios (ORs) and 95% confidence intervals (CIs) for gastric cancer were calculated. Interaction effects between the SNPs and phytoestrogen biomarkers (genistein, daidzein, equol, and enterolactone) were computed. CDK1 rs4145643, FAS rs6586161, and FAS rs1468063 in the AKT signaling pathway presented significant genetic effects on gastric cancer (OR = 0.81 (95% CI: 0.66-0.99) for CDK1 rs4145643; OR = 1.27 (95% CI: 1.03-1.58) for FAS rs6586161; OR = 1.29 (95% CI: 1.03-1.56) for FAS rs1468063; Cochran Q statistics > 0.10). Risk alleles of FAS rs6586161, FAS rs1468063, MAP3K1 rs16886448, and MAP3K1 rs252902 showed significant interaction effects with enterolactone (p(interaction) < 0.05).

CONCLUSION

CDK1 and FAS genes involved in AKT signaling and influenced by anti-carcinogenic property of phytoestrogens can play a role as susceptible genetic factors in gastric carcinogenesis. FAS and MAP3K1 genes significantly interact with enterolactone, thereby modifying the individual's risk for gastric cancer.

Urinary estrogen metabolites in two soy trials with premenopausal women

Background

Soy consumption may protect against breast cancer through modification of estrogen metabolism.

Objective

We examined the effect of soy foods on urinary estrogens and the 2-hydroxy (OH)/16α-OH estrone (E₁) ratio in 2 dietary interventions with premenopausal women.

Methods

BEAN1 was a 2-year randomized trial and BEAN2 a 13-month randomized crossover study. In both interventions, study participants consumed a high-soy diet with 2 soy food servings/day and a low-soy diet with <3 servings of soy/week. Urine samples were collected at baseline and at the end of the diet periods, analyzed for 9 estrogen metabolites by liquid chromatography mass spectrometry, and adjusted for creatinine levels. For BEAN1, 2 samples for 188 participants and for BEAN2, 3 samples for 79 women were analyzed. We applied mixed-effects regression models with log-transformed values of estrogen metabolites and soy intake as the exposure variable.

Results

In BEAN1, no effect of the high-soy diet on individual estrogen metabolites or hydroxylation pathways was observed. The median 2-OH/16α-OH E₁ ratio decreased non-significantly in the intervention group from 6.2 to 5.2 as compared to 6.8 and 7.2 in the control group (p=0.63). In BEAN2, only 4-OHE₁ was significantly lower after the high-soy diet. Interaction terms of the high-soy diet with equol producer status, ethnicity, and weight status revealed no significant effect modification.

Conclusions

Contrary to our hypothesis and some previous reports, the results from 2 well controlled dietary interventions do not support an effect of a high-soy diet on a panel of urinary estrogen metabolites and the 2-OH/16α-OHE₁ ratio.

The relation of urinary estrogen metabolites with mammographic densities in premenopausal women

BACKGROUND

Mammographic density is a strong predictor of breast cancer risk. The total amount and the metabolism of endogenous estrogens, e.g., the ratio of 2-hydroxyestrone (2-OHE(1)) and 16α-OHE(1) may influence breast cancer risk. This study examined the association of urinary estrogen metabolites with breast density in premenopausal women.

METHODS

Urine samples were collected at baseline and after 2 years, analyzed for 11 estrogen metabolites plus progesterone and testosterone by liquid chromatography mass spectrometry, and adjusted for creatinine levels. Mixed-effects regression was applied to examine the association of estrogens with breast density.

RESULTS

Total estrogen metabolites (181 ± 113 vs. 247 ± 165 pmol/mg creatinine, p=0.01) and the 2/16α-OH ratio (8.4 ± 10.4 vs. 13.0 ± 17.1, p=0.02) were lower in the 74 Asian than in the 114 non-Asian women. In adjusted models, positive associations of total estrogen metabolites (p=0.002) and the 2/16α-OHE(1) ratio (p=0.08) with percent density were detected in Asians only. In all women, mammographic density was positively associated with the 2-OH pathway (p=0.01), inversely related to the 16α-OH pathway (p=0.01), and not associated with the 4-OH pathway, testosterone, and progesterone. Results for the size of the dense area weakly reflected the findings for percent density, while associations with the non-dense area were in the opposite direction.

CONCLUSIONS

The findings that the 2-OH pathway is associated with higher and the 16α-OH pathway with lower breast density contradicts the hypothesized risk profile of these metabolites, but, if a relation between estrogen metabolites and breast cancer risk exists, it may be mediated through pathways other than mammographic density.

Prevention of rat breast cancer by genistin and selenium

Breast cancer is the second leading cause of cancer death among women and the third most common cancer. In this study, we investigated the chemoprevention efficacy of each of soy genistin, selenium or a combination of them against breast cancer. Seventy-five female rats were divided into five groups : control group (I); 7,12-dimethylbenz(a)anthracene (DMBA) group (II); DMBA treated with genistin group (III); DMBA treated with selenium group (IV); and DMBA treated with genistin combined with selenium group (V). The treatments were daily administered for 3 months. There were a significant decrease in body weight and serum total antioxidant, while a significant elevation in serum total sialic acid, carcinoembryonic antigen, prolactin, estradiol, nitric oxide, and malondialdhyde of DMBA injected rats compared with control group. Administration of genistin and selenium was associated with decreasing levels of tumorigenicity, endocrine derangement, and oxidative stress. Formation of breast carcinoma in DMBA-induced rats and abnormal changes were ameliorated in the rats treated with genistin/selenium or genistin alone. Supplementation of genistin alone or with selenium provided antioxidant defense with high-potential chemopreventive activity against DMBA-induced mammary tumors more than selenium alone.

Adolescent lifestyle factors and adult breast density in U.S. Chinese immigrant women

We examined recalled measures of adolescent diet, physical activity, and body size in relation to adult breast density in 201 U.S. Chinese immigrant women recruited in January 2002 to May 2003 from Philadelphia region screening programs. Mammographic images were classified into 1 of 4 categories ranging from "entirely fatty" to "extremely dense." Questionnaires assessed diet and physical activity between ages 12-17, relative weight and height at age 10, and weight at age 18. To estimate odds ratios (ORs), we conducted logistic regression analyses using proportional odds models for polychotomous outcomes. Higher adult breast density was significantly associated with adolescent red meat intake (adjusted 3rd vs. 1st tertile OR = 3.0, 95% confidence interval (CI) 1.5-6.4, trend P = 0.003) but not with other adolescent factors. For the association of adult acculturation with breast density, adjustment for adolescent red meat intake attenuated the OR for the highest vs. lowest level of acculturation from 2.5 (95% CI 1.2-5.3) to 1.9 (95% CI 0.9-4.0). Greater adolescent red meat intake may have increased adult breast density and partly accounted for the strong association between acculturation and breast density in this sample of immigrant Chinese women. If confirmed by further study, dietary prevention efforts for breast cancer should be considered earlier in life.

The volume of nipple aspirate fluid is not affected by 6 months of treatment with soy foods in premenopausal women

Based on the hypothesis that soy food consumption may influence breast tissue activity, we examined its effect on the production of nipple aspirate fluid (NAF), a possible indicator of breast cancer risk. Of 310 premenopausal women screened, 112 (36%) produced at least 10 μL of NAF, the minimum for study participation. In a crossover design, we randomized 96 women to 2 groups who, in reverse order, consumed a high-soy diet with 2 soy servings/d (1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts) and a low-soy diet with <3 servings/wk of soy for 6 mo each separated by a 1-mo washout period. During each diet period, 3 NAF samples were obtained (baseline and 3 and 6 mo) using a FirstCyte Aspirator and 4 urine samples (baseline and 1, 3, and 6 mo) were analyzed for isoflavonoids by liquid chromatography tandem MS. Adherence to the study protocol according to 24-h dietary recalls and urinary isoflavonoid excretion was high. The drop-out rate was 15% (n = 14); 82 women completed the intervention. The 2 groups produced similar mean NAF volumes at baseline (P = 0.95) but differed in age and previous soy intake and in their response to the intervention (P = 0.03). In both groups, NAF volume decreased during the first 3 mo of the high-soy diet period and returned to baseline at 6 mo, but there was no effect of the high-soy diet on NAF volume (P = 0.50 for diet; P-interaction = 0.21 for diet with time). Contrary to an earlier report, soy foods in amounts consumed by Asians did not increase breast tissue activity as assessed by NAF volume.

Adult ovarian function can be affected by high levels of soy

Ovarian function in adults is controlled by hormones circulating in the body. The primary hormone responsible for cyclicity in animals and humans is estrogen. Estrogen is mostly produced in the ovary and enters the circulation where it then signals the brain for a response. The parts of the brain that controls reproductive hormones are the hypothalamus and anterior pituitary. Estrogen stimulates the hypothalamus to produce gonadotropin releasing hormone, which in turn signals the anterior pituitary to produce follicle stimulating hormone and luteinizing hormone. These hormones enter the circulation and signal the ovary to ovulate. Substances with estrogenic activity can potentially interfere with this signaling if levels of activity are sufficient to cause a response. Soy foods contain estrogenic substances called phytoestrogens. The predominant phytoestrogens found in soy are genistein and daidzein. The female reproductive system is dependent on hormones for proper function and phytoestrogens at very high levels can interfere with this process. This paper summarizes the literature on adult soy consumption and its effect on ovarian function.

Is soy consumption good or bad for the breast?

Genistein in soy activates estrogen receptor (ER)-α and ERβ and acts as an estradiol in multiple target tissues. Because estrogens increase breast cancer risk and genistein promotes the growth of ER-positive human breast cancer cells, it has remained unclear whether this isoflavone or soy is safe. Results reviewed here suggest that women consuming moderate amounts of soy throughout their life have lower breast cancer risk than women who do not consume soy; however, this protective effect may originate from soy intake early in life. We also review the literature regarding potential risks genistein poses for breast cancer survivors. Findings obtained in 2 recent human studies show that a moderate consumption of diet containing this isoflavone does not increase the risk of breast cancer recurrence in Western women, and Asian breast cancer survivors exhibit better prognosis if they continue consuming a soy diet. The mechanisms explaining the breast cancer risk-reducing effect of early soy intake or the protective effect in Asian breast cancer survivors remain to be established. We propose that the reduction in risk involves epigenetic changes that result in alterations in the expression of genes that regulate mammary epithelial cell fate, i.e. cell proliferation and differentiation. Lifetime soy consumption at a moderate level may prevent breast cancer recurrence through mechanisms that change the biology of tumors; e.g. women who consumed soy during childhood develop breast cancers that express significantly reduced Human epidermal growth factor receptor 2 levels. More research is needed to understand why soy intake during early life may both reduce breast cancer risk and risk of recurrence.

Associations between obesity and serum lipid-soluble micronutrients among premenopausal women

Elucidating potential pathways that micronutrients may reduce/promote chronic disease may contribute to our understanding of the underlying etiology of disease and their utility as markers of risk. In the current study, we examined associations of serum lipid-soluble micronutrients with body mass index (BMI). We hypothesized that obesity may differentially influence serum micronutrient levels, thereby affecting risk for chronic disease incidence and mortality. Baseline serum samples from 180 premenopausal women from a nutritional trial were analyzed for leptin, C-reactive protein, 25-hydroxyvitamin D, carotenoids, and tocopherols. Participants were stratified into normal-weight (18.5-24.9), overweight (25-29.9), and obese (>or=30) subgroups by BMI (in kilograms per square meter). Differences in serum biomarkers among BMI subgroups were adjusted for Asian ethnicity and smoking status. As expected, obese individuals had significantly higher serum levels of leptin and C-reactive protein (Ps < .05) compared with normal-weight women. gamma-Tocopherol levels were significantly higher in obese individuals (P < .05), whereas alpha-tocopherol levels did not differ among BMI subgroups. Serum levels of 25-hydroxyvitamin D and carotenoids (except lycopene) were significantly lower in obese than in normal-weight women (Ps < .05). The associations between BMI and carotenoids were independent of dietary intake. The obesity-associated reduction for total provitamin A carotenoids (45%) was approximately 3-fold greater than that observed for non-provitamin A carotenoids (16%). Our results indicate potential influences of obesity on serum levels of lipid-soluble micronutrients and suggest that metabolism of provitamin A carotenoids may contribute to the differences observed.

Effects of isoflavones on breast density in pre- and post-menopausal women: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Isoflavones from soy and red clover exert modest hormonal effects in women, but the relevance to risk of breast cancer is unclear. The aim of this meta-analysis was to assess the effects of isoflavone-rich foods or supplements on a biomarker of breast cancer risk, women's mammographic density.

METHODS

Electronic searches were performed on The Cochrane Library, Medline and EMBASE (to June 2009), and reference lists and trial investigators were consulted to identify further studies. Randomized controlled trials (RCTs) of isoflavone-rich foods or supplements versus placebo with a duration of at least 6 months were included in our analysis. Inclusion/exclusion, data extraction and validity assessment were carried out independently in duplicate, and meta-analysis used to pool study results. Subgrouping, sensitivity analysis, assessment of heterogeneity and funnel plots were used to interpret the results.

RESULTS

Eight RCTs (1287 women) compared isoflavones with placebo for between 6 months and 3 years. Meta-analysis suggested no overall effect of dietary isoflavones on breast density in all women combined [mean difference (MD) 0.69%, 95% confidence interval (CI) -0.78 to 2.17] or post-menopausal women (MD -1.10%, 95% CI -3.22 to 1.03). However, there was a modest increase in mammographic density in premenopausal women (MD 1.83%, 95% CI 0.25-3.40) without heterogeneity but this effect was lost in one of three sensitivity analyses.

CONCLUSIONS

Isoflavone intake does not alter breast density in post-menopausal women, but may cause a small increase in breast density in premenopausal women. Larger, long-term trials are required to determine if these small effects are clinically relevant.

The pros and cons of phytoestrogens

Phytoestrogens are plant derived compounds found in a wide variety of foods, most notably soy. A litany of health benefits including a lowered risk of osteoporosis, heart disease, breast cancer, and menopausal symptoms, are frequently attributed to phytoestrogens but many are also considered endocrine disruptors, indicating that they have the potential to cause adverse health effects as well. Consequently, the question of whether or not phytoestrogens are beneficial or harmful to human health remains unresolved. The answer is likely complex and may depend on age, health status, and even the presence or absence of specific gut microflora. Clarity on this issue is needed because global consumption is rapidly increasing. Phytoestrogens are present in numerous dietary supplements and widely marketed as a natural alternative to estrogen replacement therapy. Soy infant formula now constitutes up to a third of the US market, and soy protein is now added to many processed foods. As weak estrogen agonists/antagonists with molecular and cellular properties similar to synthetic endocrine disruptors such as Bisphenol A (BPA), the phytoestrogens provide a useful model to comprehensively investigate the biological impact of endocrine disruptors in general. This review weighs the evidence for and against the purported health benefits and adverse effects of phytoestrogens.

Effectiveness of phytoestrogens in climacteric medicine

The increased interest in phytoestrogens in the management of menopausal symptoms followed the publication of the Women's Health Initiative study. A wide-spread perception that these plant-derived compounds are equivalent to estrogen was established. These compounds evolved to fulfill the needs of plant physiological processes and are natural for the plant cells but not natural to the human cell. Epidemiological data suggest a possible protective effect of phytoestrogen if consumed during adolescence, but later on in life this effect is not clear. The utility of phytoestrogen as a "natural and safe" alternative to estrogen in alleviating vasomotor symptoms has failed the test in randomized clinical trials. Because many breast cancer sufferers seek in phytoestrogen a relief of estrogen deficiency symptoms, the possible interaction of such remedies with risk of recurrence of breast cancer or interference with tamoxifen action should not be overlooked.

Comparison of breast density measured by dual energy X-ray absorptiometry with mammographic density among adult women in Hawaii

BACKGROUND

While use of mammography is limited, due to concerns related to radiation exposure, dual energy X-ray absorptiometry (DXA), commonly available in medical care settings, is characterized by low radiation exposure.

METHODS

In the current paper, we compared breast density measured by DXA with mammographic density in 101 adult women who had a screening mammogram during the last 2 years. DXA scans of both breasts were taken using a clinical DXA system calibrated to measure breast density. The total projected breast area was manually delineated on each image and percent fibroglandular volume density (%FGV), absolute fibroglandular volume, total breast area and volume were computed. After digitizing mammographic films, total breast area, dense area, and percent density (PD) were estimated using computer-assisted mammographic density assessment.

RESULTS

Both DXA and mammographic measures showed high correlations between left and right breasts ranging from 0.85 to 0.98 (p<0.0001). Mean %FGV was 38.8±14.3%, and mean percent density was 31.9±18.2% for craniocaudal views and 28.3±16.2% for mediolateral views. The correlation between the two measures was 0.76 for both views (p<0.0001). Associations with common risk factors showed similar patterns for DXA and mammographic densities; in particular, the inverse associations with BMI and age at menarche were evident for both methods. Multilinear regression with stepwise selection indicated an explained variance of 0.56 for %FGV alone and of 0.58 for %FGV plus number of children.

CONCLUSION

Despite some differences in methodology, the current comparison suggests that DXA may provide a low-radiation option in evaluating breast density.

Physical activity and change in mammographic density: the Study of Women's Health Across the Nation

One potential mechanism by which physical activity may protect against breast cancer is by decreasing mammographic density. Percent mammographic density, the proportion of dense breast tissue area to total breast area, declines with age and is a strong risk factor for breast cancer. The authors hypothesized that women who were more physically active would have a greater decline in percent mammographic density with age, compared with less physically active women. The authors tested this hypothesis using longitudinal data (1996-2004) from 722 participants in the Study of Women's Health Across the Nation (SWAN), a multiethnic cohort of women who were pre- and early perimenopausal at baseline, with multivariable, repeated-measures linear regression analyses. During an average of 5.6 years, the mean annual decline in percent mammographic density was 1.1% (standard deviation = 0.1). A 1-unit increase in total physical activity score was associated with a weaker annual decline in percent mammographic density by 0.09% (standard error = 0.03; P = 0.01). Physical activity was inversely associated with the change in nondense breast area (P < 0.01) and not associated with the change in dense breast area (P = 0.17). Study results do not support the hypothesis that physical activity reduces breast cancer through a mechanism that includes reduced mammographic density.

The relation of leptin and adiponectin with breast density among premenopausal women

The adipocytokine leptin may increase breast cancer risk, while adiponectin may be protective. We examined the association of the two circulating markers with mammographic density, a strong predictor of breast cancer risk. For 183 premenopausal participants of a nutritional trial, mammograms performed at baseline, year 1 and year 2 were assessed for density using a computer-assisted method. Serum samples obtained at the same time were analyzed for leptin and adiponectin by enzyme-linked immunosorbent assay. We applied mixed models to incorporate the repeated measurements while adjusting for confounders including body mass index (BMI). At baseline, the mean age of the participants was 42.6+/-2.9 years; 40% were of Asian ancestry. Leptin was lower and adiponectin higher in normal weight than overweight women. Neither marker was related to absolute breast density. The significant inverse association of leptin with percent density disappeared when BMI was added to the model. After stratification by weight, percent density decreased with higher leptin levels in normal weight women, whereas it increased among overweight participants. After adjustment for BMI, the positive association between percent density and adiponectin was greatly reduced and no longer significant. These results do not support a strong association of leptin or adiponectin with breast cancer risk as assessed by mammographic density. In contrast, the findings suggest the possibility that the inverse association of BMI with breast cancer risk in premenopausal women is mediated by adipocytokines.

Serum 25-hydroxyvitamin D levels and mammographic density among premenopausal women in a multiethnic population

Although some evidence suggests a protective role of vitamin D against breast cancer, epidemiological findings are inconsistent. The current study investigated the relation of serum 25-hydroxyvitamin D (25(OH)D) levels with mammographic density. Baseline serum samples from 182 premenopausal women including 67 Caucasians and 74 Asians from a nutritional trial were analyzed for 25(OH)D. Mammographic density was assessed using a computer-assisted method. Serum 25(OH)D was not associated with mammographic density after adjustment for confounders (body mass index (BMI), age at mammogram, Asian ethnicity, age at first birth, parity and age at menarche). 25(OH)D levels were significantly lower in Asians than in Caucasians, but no significant ethnic differences in mammographic density were observed after adjusting for BMI. Although the current results indicate that serum 25(OH)D levels were not associated with mammographic density among premenopausal women, a possible protective effect of vitamin D against breast cancer may be mediated through other pathways.

Epidemiologic studies of isoflavones & mammographic density

Isoflavones, phytoestrogens in soy beans with estrogen-like properties, have been examined for their cancer protective effects. Mammographic density is a strong predictor of breast cancer. This review summarizes studies that have examined the association between isoflavones and breast density. Observational investigations in Hawaii and Singapore suggest slightly lower breast density among women of Asian descent with regular soy intake, but two larger studies from Japan and Singapore did not observe a protective effect. The findings from seven randomized trials with primarily Caucasian women indicate that soy or isoflavones do not modify mammographic density. Soy foods and isoflavone supplements within a nutritional range do not appear to modify breast cancer risk as assessed by mammographic density.

Side effects of phytoestrogens: a meta-analysis of randomized trials

BACKGROUND

Phytoestrogens are widely used by postmenopausal women for the treatment of the climacteric syndrome. The risk of adverse effects of this treatment, however, is unknown.

METHODS

Using a fixed-effects model, we performed a meta-analysis of side effects comparing phytoestrogen treatment with placebo or no treatment in randomized controlled trials.

RESULTS

We identified 174 randomized controlled trials. Side effects were reported in 92/174 randomized controlled trials with 9629 participants. The overall incidence of side effects in the phytoestrogen and control groups was 2019/5502 (36.7%) and 1824/4806 (38.0%), respectively (P=.2; incidence rate ratio [IRR] 1.01; 95% confidence interval [CI], 0.95-1.08). Comparing various side effect categories, we found significantly higher rates of gastrointestinal side effects among phytoestrogen users (P=.003; IRR 1.28; 95% CI, 1.08-1.50). Gynecological (IRR 0.94; 95% CI, 0.74-1.20), musculoskeletal (IRR 1.20; 95% CI, 0.94-1.53), neurological (IRR 0.91; 95% CI, 0.70-1.19), and unspecific side effects (IRR 0.95; 95% CI, 0.88-1.03) were not significantly different between groups. Within side effect categories, we found no significantly higher rates of side effects in women using phytoestrogens. Specifically, the rates of hormone-related side effects such as endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly different between groups.

CONCLUSIONS

Based on the available evidence, phytoestrogen supplements have a safe side-effect profile with moderately elevated rates of gastrointestinal side effects. Rates of vaginal bleeding, endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly increased among phytoestrogen users in the investigated studies.

The effect of genistein aglycone on cancer and cancer risk: a review of in vitro, preclinical, and clinical studies

In Asian epidemiological studies, health benefits, including reduced incidence of breast and prostate cancers, are attributed to soy food and isoflavone consumption. The recent increased intake of soy foods and supplements in the American diet has raised concerns about the possible estrogen-like effects of natural isoflavones and possible promotion or propagation of estrogen-sensitive cancers. These concerns are primarily based on in vitro and rodent data which suggest that genistein aglycone can stimulate tumor cell proliferation and growth in mice having deficient immune systems. In contrast, a recent nested case-control study and meta-analysis of numerous epidemiological studies show an inverse correlation between genistein intake and breast cancer risk. Furthermore, clinical studies in osteopenic and osteoporotic, postmenopausal women support the breast and uterine safety of purified naturally derived genistein administered for up to 3 years. In this review, we summarize the in vitro, preclinical and clinical evidence for the safety of natural genistein.

Estrogen/isoflavone interactions in cynomolgus macaques (Macaca fascicularis)

Soy isoflavones are phytoestrogenic components of dietary soy, which are widely consumed for their potential health benefits. Soy isoflavones appear to decrease breast and endometrial cancer risk in human observational studies, but paradoxically stimulate growth of breast cancer cells in culture and uterine enlargement in rodents. We have shown that these compounds are not estrogenic in cynomolgus monkeys even at relatively high doses, but that they reduce estrogen-induced proliferative responses of the breast and endometrium. This effect may be mediated through estrogen receptor interactions and/or modulation of endogenous estrogen metabolism. Interindividual variation in isoflavone absorption and metabolism contributes to the degree of estrogen antagonistic effect. Our recent studies have also shown that individual isoflavone metabolites such as glyceollins may have unique selective estrogen receptor modulator-like activity, acting as tissue-specific antagonists without agonist activity. Rodent studies and human epidemiologic data suggest that timing of exposure and dose relative to endogenous estrogen concentrations are important determinants of effect, and studies of dietary soy on breast development and pubertal maturation are under way. Because soy isoflavones are both abundant in standard monkey chow diets and widely available as dietary supplements for human beings, these findings have broad relevance to the health of human and nonhuman primates.

Various doses of soy isoflavones do not modify mammographic density in postmenopausal women

Soy isoflavones have functional similarity to human estrogens and may protect against breast cancer as a result of their antiestrogenic activity or increase risk as a result of their estrogen-like properties. We examined the relation between isoflavone supplementation and mammographic density, a strong marker for breast cancer risk, among postmenopausal women. The Osteoporosis Prevention Using Soy (OPUS) study, a multi-site, randomized, double-blinded, and placebo-controlled trial assigned 406 postmenopausal women to 80 or 120 mg/d of isoflavones each or a placebo for 2 y. Percent densities were assessed in digitized mammograms using a computer-assisted method. The mammogram reader did not know the treatment status and the time of mammograms. We applied mixed models to compare breast density by treatment while considering the repeated measures. The mammographic density analysis included 358 women, 88.2% of the OPUS participants; 303 had a complete set of 3 mammograms, 49 had 2, and 6 had only 1 mammogram. At baseline, the groups were similar in age, BMI, and percent density, but mean breast density differed by study site (P = 0.02). A model with all mammograms did not show a treatment effect on any mammographic measure, but the change over time was significant; breast density decreased by 1.6%/y across groups (P < 0.001). Stratification by age and BMI did not reveal any effects in subgroups. In this randomized 2-y trial, isoflavone supplements did not modify breast density in postmenopausal women. These findings offer reassurance that isoflavones do not act like hormone replacement medication on breast density.

Inflammatory markers in a 2-year soy intervention among premenopausal women

BACKGROUND

Epidemiologic evidence supports a role of soy foods in breast cancer etiology. Because chronic inflammation appears to be a critical component in carcinogenesis, we examined the potential anti-inflammatory effects of soy foods.

METHODS

The original 2-year dietary intervention randomized 220 premenopausal women of whom 183 women (90 in the intervention group and 93 in the control group) were included in the current investigation; 40% were of Asian ancestry. The intervention group consumed two daily soy servings containing 50 mg of isoflavones (aglycone equivalents), whereas the controls maintained their regular diet. Five serum samples obtained at month 0, 3, 6, 12, and 24 were analyzed for interleukin (IL)-6, C-reactive protein (CRP), leptin, and adiponectin by ELISA. For statistical analysis, mixed models were applied to incorporate the repeated measurements.

RESULTS

The levels of all analytes were lower in Asian than Caucasian women. Overweight women had significantly higher levels of CRP, IL-6, and leptin and lower levels of adiponectin than normal weight women. We did not observe a significant effect of soy foods on the four markers, but leptin increased in the control and not in the intervention group (p = 0.20 for group-time effect); this difference was significant for Asian (p = 0.01) and obese women (p = 0.005).

CONCLUSION

During this 2-year intervention, soy foods did not modify serum levels of CRP, IL-6, leptin, and adiponectin in premenopausal women although leptin levels remained stable among women in the intervention group who were obese or of Asian ancestry. Further studies with diverse markers of inflammation are necessary to clarify the specific effect of soy on immune responses.

Green tea, soy, and mammographic density in Singapore Chinese women

There is increasing evidence from observational studies that breast cancer risk is inversely associated with soy and green tea consumption. We investigated the effects of these two dietary agents on mammographic density, a well-established biomarker for breast cancer risk, in a cross-sectional analysis of mammograms and validated food frequency questionnaires from 3,315 Chinese women in Singapore. Percent mammographic density (PMD) was assessed using a reproducible computer-assisted method. We used generalized linear models to estimate PMD by intake of soy, green tea, and black tea while adjusting for potential confounders. Daily green tea drinkers showed statistically significantly lower PMD (19.5%) than non-tea drinkers (21.7%; P = 0.002) after adjusting for relevant covariates. This difference in PMD between daily green tea drinkers and non-tea drinkers remained statistically significant after adjustment for soy (P = 0.002); the effect was more apparent among lower soy consumers (Q1-Q3; 21.9% versus 19.4%; P = 0.002) than in higher (Q4) consumers (20.9% versus 19.5%; P = 0.32). Black tea intake was unrelated to PMD. Only among postmenopausal women who reported very high soy intake (Q4) compared with those with less soy intake was there any association noted between PMD and soy intake (18.9% versus 20.5%; P = 0.035). Following adjustment for green tea intake, the association between soy and PMD was no longer statistically significant (P = 0.52). Our findings suggest that both regular green tea and high soy intake may have beneficial effects on the breast; the effect of green tea on PMD may be stronger than the effect of soy.