Phytoestrogens and lung cancer risk: a nested case-control study in never-smoking Chinese women.

BACKGROUND: Since several lines of evidence suggest that estrogens may be involved in lung carcinogenesis, it has been hypothesized that intake of phytoestrogens, similar in molecular structure to mammalian estrogens, may be associated with lung cancer development. OBJECTIVE: The aim was to prospectively evaluate the association between phytoestrogen exposure and lung cancer risk in never-smoking women. METHODS: We conducted a nested case-control study within a population-based prospective cohort study of women. A total of 478 incident lung cancer cases and their individually matched controls were identified among never-smoking women after a mean follow-up of 15.6 years. Habitual intake of and internal exposure to phytoestrogens were assessed by repeated dietary surveys and urinary biomarkers, respectively. ORs and 95% CIs for lung cancer were estimated in conditional logistic regression models. RESULTS: After adjustment for potential confounders, a moderate intake of dietary isoflavones was inversely associated with lung cancer risk in never-smoking women, with the OR for the second quartile vs. the lowest quartile of intake being 0.52 (95% CI: 0.35, 0.76). Further increasing intake did not convey additional benefits, with ORs (95% CI) for the third and fourth quartiles of 0.53 (0.36, 0.78) and 0.47 (0.31, 0.72), respectively (P-overall < 0.001 and P-nonlinearity = 0.006). A similar association was seen when exposure to isoflavones was assessed by urinary biomarkers. ORs (95% CI) for the second, third, and fourth quartiles compared with the lowest quartile of urinary isoflavone excretion were 0.57 (0.39, 0.83), 0.64 (0.44, 0.92), and 0.60 (0.41, 0.86), respectively. The inverse association reached a plateau beyond the second quartile, with P-overall = 0.04 and P-nonlinearity = 0.15. Urinary excretion of gut-microbiota-derived metabolites of lignans was not related to lung cancer risk. CONCLUSIONS: This study suggests that moderately increasing intake of isoflavone-rich foods is associated with lower risk of lung cancer in never-smoking women.

Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial.

Background: Previous in vitro and in vivo studies indicate that enzymes that synthesize and metabolize vitamin D are magnesium dependent. Recent observational studies found that magnesium intake significantly interacted with vitamin D in relation to vitamin D status and risk of mortality. According to NHANES, 79% of US adults do not meet their Recommended Dietary Allowance of magnesium. Objectives: The aim of this study was to test the hypothesis that magnesium supplementation differentially affects vitamin D metabolism dependent on baseline 25-hydroxyvitamin D [25(OH)D] concentration. Methods: The study included 180 participants aged 40-85 y and is a National Cancer Institute independently funded ancillary study, nested within the Personalized Prevention of Colorectal Cancer Trial (PPCCT), which enrolled 250 participants. The PPCCT is a double-blind 2 × 2 factorial randomized controlled trial conducted in the Vanderbilt University Medical Center. Doses for both magnesium and placebo were customized based on baseline dietary intakes. Subjects were randomly assigned to treatments using a permuted-block randomization algorithm. Changes in plasma 25-hydroxyvitamin D3 [25(OH)D3], 25-hydroxyvitamin D2 [25(OH)D2], 1,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D2, and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were measured by liquid chromatography-mass spectrometry. Results: The relations between magnesium treatment and plasma concentrations of 25(OH)D3, 25(OH)D2, and 24,25(OH)2D3 were significantly different dependent on the baseline concentrations of 25(OH)D, and significant interactions persisted after Bonferroni corrections. Magnesium supplementation increased the 25(OH)D3 concentration when baseline 25(OH)D concentrations were close to 30 ng/mL, but decreased it when baseline 25(OH)D was higher (from ∼30 to 50 ng/mL). Magnesium treatment significantly affected 24,25(OH)2D3 concentration when baseline 25(OH)D concentration was 50 ng/mL but not 30 ng/mL. On the other hand, magnesium treatment increased 25(OH)D2 as baseline 25(OH)D increased. Conclusion: Our findings suggest that optimal magnesium status may be important for optimizing 25(OH)D status. This trial was registered at clinicaltrials.gov as NCT03265483.

Pharmacokinetics and safety profile of single-dose administration of an estrogen receptor ß-selective phytoestrogenic (phytoSERM) formulation in perimenopausal and postmenopausal women.

OBJECTIVE: Selected estrogen receptor ß-selective phytoestrogen (phytoSERM), a preparation of genistein, daidzein, and S-equol, has an 83-fold selective affinity for estrogen receptor (ER) ß, and may promote neuronal survival and estrogenic mechanisms in the brain without exerting feminizing activity in the periphery. The aim of this study was to assess the safety, tolerability, and single-dose pharmacokinetics of the phytoSERM formulation in perimenopausal and postmenopausal women. METHODS: Eighteen women aged 45 to 60 years from a 12-week clinical trial evaluating cognitive performance and vasomotor symptoms were randomly assigned to placebo, 50 mg, or 100 mg phytoSERM treatment groups. Plasma levels of the three parent phytoestrogens and their metabolites were measured before and at 2, 4, 6, 8, and 24 hours after ingestion by isotope dilution high-performance liquid chromatography (HPLC) electrospray ionization tandem mass spectrometry. RESULTS: Plasma concentrations of genistein, daidzein, and S-equol peaked at 9, 6, and 4 hours, respectively, for the 50-mg dose, and at 6, 6, and 5 hours, respectively, for the 100-mg dose. The maximum concentration (Cmax) and area under the curve (AUC) for the three parent compounds were greater in the 100-mg dose group, indicating a dose-dependent change in concentration with the phytoSERM treatment. No adverse events were elicited. CONCLUSIONS: A single-dose oral administration of the phytoSERM formulation was well-tolerated and did not elicit any adverse events. It was rapidly absorbed, reached high plasma concentrations, and showed a linear dose-concentration response in its pharmacokinetics. These findings are consistent with previously reported parameters for each parent compound (Clinicaltrials.gov NCT01723917).

Beneficial effects of soy supplementation on postmenopausal atherosclerosis are dependent on pretreatment stage of plaque progression.

OBJECTIVE: The objective of this study was to use a well-established monkey model of atherosclerosis to determine how life stage and preexisting atherosclerosis influence the effectiveness of high-isoflavone soy diet in inhibiting progression of atherosclerosis. METHODS: For 34 months, premenopausal monkeys were fed an atherogenic diet, with protein derived primarily from either animal sources (casein-lactalbumin [CL], n = 37) or high-isoflavone soy beans (Soy, n = 34). Animals were ovariectomized and randomized to groups fed the same diet (CL-CL, n = 20; Soy-Soy, n = 17) or an alternate diet (CL-Soy, n = 17; Soy-CL, n = 17) for an additional 34 months. At ovariectomy, the left common iliac artery was removed to determine the amount of premenopausal atherosclerosis. At necropsy, the right common iliac artery and coronary arteries were collected, and atherosclerosis extent was quantified. CL-CL condition was considered "control." RESULTS: Modeling Asian women who remain in Asia, monkeys fed soy protein both premenopausally and postmenopausally had a markedly reduced extent of coronary artery atherosclerosis relative to CL controls (P = 0.008). The subset of animals that modeled Asian women who migrate to a Western country (consuming soy premenopausally and CL postmenopausally) had increased progression of postmenopausal iliac artery atherosclerosis (P = 0.003) and was not protected against the development of coronary artery atherosclerosis relative to controls. Relevant to the administration of soy diets to postmenopausal Western women, monkeys fed CL premenopausally and switched to soy postmenopausally derived atheroprotective benefits only if they began the postmenopausal treatment period with relatively small (below the median) plaques. Relative to controls, this group (with small plaques at ovariectomy) had reduced progression of iliac atherosclerosis (P = 0.038) and smaller coronary artery plaques (P = 0.0001) that were less complicated (P = 0.05) relative to controls. CONCLUSIONS: The results suggest that significant atheroprotective benefits of dietary soy are derived from treatment that begins premenopausally and continues postmenopausally or from treatment that is started during early postmenopause (when plaques are still small).

Associations between urine excretion of isoflavonoids and cognition in postmenopausal women in the Women's Isoflavone Soy Health clinical trial.

OBJECTIVES: To determine effect of change in urine excretion of isoflavonoids on cognitive change. DESIGN: Post hoc analysis of isoflavonoid exposure (mean 2.7 years) during the randomized, placebo-controlled, double-blind Women's Isoflavone Soy Health trial. SETTING: General community. PARTICIPANTS: Healthy postmenopausal women (N = 350). INTERVENTION: Twenty-five grams of isoflavone-rich soy protein (91 mg of aglycone weight isoflavones: 52 mg genistein, 36 mg daidzein, 3 mg glycitein) or milk protein-matched placebo provided daily. MEASUREMENTS: Overnight urine excretion, fasting plasma levels of isoflavonoids, and cognitive function measured at baseline and endpoint. RESULTS: Three hundred women (age: mean 61, range 45-92) completed both cognitive assessments and did not use hormone replacement therapy during the trial. Mean on-trial change from baseline in urine excretion of isoflavonoids was not significantly associated with change in a composite score of global cognition (P = .39). Secondary analyses indicated that change in urine excretion of isoflavonoids was inversely associated with change in a factor score representing general intelligence (P = .02) but not with factor scores representing verbal or visual episodic memory. Mean differences in this general intelligence factor score between women in the lowest and highest quartiles of isoflavonoid change were equivalent to an approximate 4.4-year age-associated decline. Analyses based on plasma isoflavonoid levels yielded similar but attenuated results. CONCLUSION: In healthy postmenopausal women, long-term changes in isoflavonoids are not associated with global cognition, supporting clinical trial results, although greater isoflavonoid exposure from dietary supplements is associated with decrements in general intelligence but not memory; this finding requires confirmation in future studies.

Oestrogen levels in serum and urine of premenopausal women eating low and high amounts of meat.

OBJECTIVE: Based on the hypothesis that high-meat diets may increase breast cancer risk through hormonal pathways, the present analysis compared oestrogens in serum and urine by meat-eating status. DESIGN: Intervention with repeated measures. SETTING: Two randomized soya trials (BEAN1 and BEAN2) among premenopausal healthy women. SUBJECTS: BEAN1 participants completed seven unannounced 24 h dietary recalls and donated five blood and urine samples over 2 years. BEAN2 women provided seven recalls and three samples over 13 months. Serum samples were analysed for oestrone (E1) and oestradiol (E2) using RIA. Nine oestrogen metabolites were measured in urine by LC-MS. Semi-vegetarians included women who reported consuming <30 g of red meat, poultry and fish daily, and pescatarians those who reported consuming <20 g of meat/poultry but >10 g of fish daily. All other women were classified as non-vegetarians. We applied mixed models to compute least-square means by vegetarian status adjusted for potential confounders. RESULTS: The mean age of the 272 participants was 41·9 (SD 4·5) years. Serum E1 (85 v. 100 pg/ml, P = 0·04) and E2 (140 v. 154 pg/ml, P = 0·04) levels were lower in the thirty-seven semi-vegetarians than in the 235 non-vegetarians. The sum of the nine urinary oestrogen metabolites (183 v. 200 pmol/mg creatinine, P = 0·27) and the proportions of individual oestrogens and pathways did not differ by meat-eating status. Restricting the models to the samples collected during the luteal phase strengthened the associations. CONCLUSIONS: Given the limitations of the study, the lower levels of serum oestrogens in semi-vegetarians than non-vegetarians need confirmation in larger populations.

Vitamin D deficiency in cord plasma from multiethnic subjects living in the tropics.

BACKGROUND: Vitamin D deficiency is commonly reported in high-latitude areas and in dark-pigmented individuals. However, nothing is known about vitamin D in cord blood from multiethnic subjects living in the tropics. OBJECTIVE: Our study objective was to determine the prevalence of vitamin D deficiency in summer and winter in cord blood from multiethnic individuals in Hawai'i where sufficient sun irradiance occurs year-round for cutaneous vitamin D production. METHODS: 25-Hydroxyvitamin D (25(OH)D) levels were quantified by enzyme immunoassay in 100 cord plasma samples from apparently healthy full-term newborns and their mothers. Stratification was performed by birth season and ethnicity. RESULTS: Mean 25(OH)D levels were 24.5 ng/mL (9.1-68.3 ng/mL). Overall, 28% of samples were vitamin D deficient (<20 ng/mL) and 50% were insufficient (20-30 ng/mL). 25(OH)D levels (ng/mL) were highest in Caucasians (30.5, n = 19), followed by Asians (25.1, n = 43), Hispanics (21.5, n = 3), Pacific Islanders (20.0, n = 25), and African Americans (19.6, n = 2). Differences among groups were significant (p = 0.008). Cord plasmas from summer versus winter were higher overall (p = 0.001) and among Asians (p = 0.0003). Seasonal changes were correlated with sun irradiance overall (r = 0.43, p = 0.0001), among Caucasians (r = 0.45, p = 0.05), and among Asians (r = 0.45, p = 0.0001). CONCLUSION: Our results suggest that prenatal supplement recommendations of 400 IU vitamin D/day do not protect against vitamin D deficiency, even in subjects living in the tropics where ample sun irradiance exists for cutaneous vitamin D synthesis. The high prevalence of vitamin D deficiency we observed emphasizes the necessity for regular 25(OH)D monitoring, particularly during pregnancy and lactation, in dark-pigmented individuals, and during winter months.

Prediagnostic serum tocopherol levels and the risk of non-hodgkin lymphoma: the multiethnic cohort.

BACKGROUND: Compromised immunity and chronic inflammation are thought to contribute to the development of non-Hodgkin lymphoma (NHL). Because tocopherols protect cells through antioxidant mechanisms, they may play a role in NHL etiology. METHODS: This nested case-control study within the Multiethnic Cohort examined the association of prediagnostic serum tocopherols levels measured in 271 NHL cases and 538 matched controls by high-pressure liquid chromatography/photodiode array detection with NHL risk. Conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI). RESULTS: We observed U-shaped associations with NHL for total and α-tocopherols [Ptrend < 0.01 for polynomial terms (3 df)]. The ORs (95% CI) for total tocopherols, which consisted primarily of α-tocopherol, were 0.41 (0.25-0.68), 0.52 (0.32-0.85), 0.39 (0.23-0.65), and 0.78 (0.47-1.29) for the second to fifth quintiles as compared with the first. The risk estimates were similar for α-tocopherol but nonsignificant for ß- and γ-tocopherol combined and for γ-tocopherol. Adjustment for serum lipids strengthened the nonlinear associations for total and α-tocopherols. Serum total tocopherol levels were higher for vitamin E supplement users at cohort entry than nonusers (21.32 ± 9.04 vs. 17.72 ± 7.43 µg/mL; P < 0.0001), but supplement use was not associated with NHL risk. No heterogeneity in risk estimates was detected by sex, ethnicity, vitamin E supplement use, or NHL subtype. CONCLUSIONS: Circulating tocopherols, at levels likely reflecting adequate dietary intakes, may be protective against NHL, whereas higher intakes from supplementation may not be beneficial. IMPACT: The association between serum tocopherol levels and NHL risk provides possible new insights into the etiology of NHL.

Effects of calcium and vitamin D supplementation on blood pressure and serum lipids and carotenoids: a randomized, double-blind, placebo-controlled, clinical trial.

PURPOSE: To estimate the effects of calcium or vitamin D supplementation or a combination of both on blood pressure and serum lipid and carotenoid levels. METHODS: Ninety-two colorectal adenoma patients were randomized in a pilot, double-blind, placebo-controlled clinical trial of supplemental vitamin D3 800 IU and elemental calcium 2.0 g (as calcium carbonate) alone or in combination in divided doses twice daily with meals over 6 months. RESULTS: Relative to placebo, mean serum triglycerides decreased 30% (P = .10) and 32% (P = .10) in the calcium and calcium plus vitamin D3 treatment groups, respectively. When the two calcium intervention groups were pooled and compared with the pooled noncalcium groups, the estimated supplemental calcium treatment effects were statistically significant for triglycerides (P = .04). Similar but nonstatistically significant decreases (5%-7%) were observed for serum total cholesterol levels. Mean systolic blood pressure increased 6% (P = .08) in the calcium group; otherwise, there were no appreciable changes in systolic or diastolic blood pressures in any active treatment group. Mean serum total carotenoid levels decreased 14% (P = .07) in the calcium and 9% (P = .10) in the calcium plus vitamin D3 groups. CONCLUSIONS: Our results suggest that supplemental calcium alone or combined with vitamin D3 but not vitamin D3 alone may reduce serum lipids and lipophilic micronutrients.

C-reactive protein, lipid-soluble micronutrients, and survival in colorectal cancer patients.

BACKGROUND: Identification of biomarkers associated with survival in patients with cancer is important for elucidating the underlying mechanisms of cancer progression and identifying possible interventions to reduce cancer morbidity and mortality. METHODS: Using stored patient plasma samples from a multiethnic population-based case-control study of invasive colorectal cancer, we measured posttreatment blood levels of C-reactive protein (CRP) and lipid-soluble micronutrients. Patients (n = 368) were followed after phlebotomy (mean of 8 years), during which time 47% died (25% colorectal cancer specific). HRs were estimated by Cox proportional hazards regression with adjustment for stage, age at diagnosis, ethnicity, sex, smoking status, and month of blood draw. RESULTS: A positive association with overall risk of death was observed for CRP [HR for highest vs. lowest quintile: 1.80; 95% confidence interval (CI), 1.07-3.04; Ptrend = 0.01], whereas inverse associations were generally observed for retinol and carotenoids (HRs for overall risk of death for the highest quintile ranging from 0.5-0.8); these associations were significant for retinol (Ptrend = 0.0002), α-carotene (Ptrend = 0.02), and total carotenoids (Ptrend = 0.02) and were generally consistent across subgroups (sex, ethnicity, cancer anatomical subtype, and stage). HRs for retinol and carotenoids were attenuated somewhat after adjustment for CRP. Similar trends for CRP were observed for colorectal cancer-specific deaths (HR for highest vs. lowest tertile: 2.06; 95% CI, 1.18-3.61; Ptrend = 0.01) as for deaths from all other causes (Pheterogeneity = 0.78). CONCLUSIONS: These observations are consistent with a direct relationship between circulating CRP and overall survival among patients with colorectal cancer. IMPACT: These results, if reproduced, suggest that reduction of inflammation should be explored as a potential complementary treatment strategy.

Endogenous and exogenous equol are antiestrogenic in reproductive tissues of apolipoprotein e-null mice.

Equol is an isoflavone (IF) metabolite produced by intestinal microbiota in a subset of people consuming dietary soy. Equol producers may show different responses to soy foods and phenotypes related to cancer risk. Here, we assessed the effects of soy IF, endogenous microbial equol production, and dietary racemic equol in a 3 × 2 × 2 factorial experiment using gnotobiotic apoE-null mice (n = 9-11/group/sex). At age 3-6 wk, equol-producing microbiota were introduced to one-half of the colony (n = 122). At age 6 wk, mice were randomized to receive a diet that contained 1 of 3 protein sources: casein and lactalbumin, alcohol-washed soy protein (low IF), and intact soy protein (high IF), with total IF amounts of 0, 42, and 566 mg/kg diet, respectively. One-half of each diet group also received racemic equol (291 mg/kg diet). After 16 wk of dietary treatment, serum isoflavonoid profiles varied with sex, soy IF amount, and intestinal microbiota status. There were no treatment effects on tissues of male mice. In females, reproductive tissue phenotypes differed by equol-producing ability (i.e., microbiota status) but not dietary equol or IF content. Equol producers had lower uterine weight, vaginal epithelial thickness, total uterine area, endometrial area, and endometrial luminal epithelial height compared with nonproducers (P < 0.05 for all), with an association between microbiota status and estrous cycle (P > chi-square = 0.03). Exogenous equol reduced expression of progesterone receptor (PGR) and the proliferation marker Ki67 (P < 0.0001) in vaginal epithelium and endometrium; for endogenous equol, only PGR was reduced (P < 0.0005). Our findings indicate that equol diminishes estrogen-dependent tissue responses in apoE-null mice.

Soy isoflavone supplementation for breast cancer risk reduction: a randomized phase II trial.

Soy isoflavone consumption may protect against breast cancer development. We conducted a phase IIB trial of soy isoflavone supplementation to examine its effect on breast epithelial proliferation and other biomarkers in the healthy high-risk breast. One hundred and twenty-six consented women underwent a random fine-needle aspiration (rFNA); those with 4,000 or more epithelial cells were randomized to a double-blind 6-month intervention of mixed soy isoflavones (PTIG-2535) or placebo, followed by repeat rFNA. Cells were examined for Ki-67 labeling index and atypia. Expression of 28 genes related to proliferation, apoptosis, and estrogenic effect was measured using quantitative reverse transcriptase PCR. Hormone and protein levels were measured in nipple aspirate fluid (NAF). All statistical tests were two-sided. Ninety-eight women were evaluable for Ki-67 labeling index. In 49 treated women, the median Ki-67 labeling index was 1.18 at entry and 1.12 post intervention, whereas in 49 placebo subjects, it was 0.97 and 0.92 (P for between-group change: 0.32). Menopausal stratification yielded similar results between groups, but within premenopausal soy-treated women, Ki-67 labeling index increased from 1.71 to 2.18 (P = 0.04). We saw no treatment effect on cytologic atypia or NAF parameters. There were significant increases in the expression of 14 of 28 genes within the soy, but not the control group, without significant between-group differences. Plasma genistein values showed excellent compliance. A 6-month intervention of mixed soy isoflavones in healthy, high-risk adult Western women did not reduce breast epithelial proliferation, suggesting a lack of efficacy for breast cancer prevention and a possible adverse effect in premenopausal women.

Effects of vitamin D3 and calcium supplementation on serum levels of tocopherols, retinol, and specific vitamin D metabolites.

γ-Tocopherol (γT) protects against DNA-damaging effects of nitrogen oxides, yet its physiologic regulation in vivo is unknown. Observational studies indicate inverse associations of 25[OH]-vitamin D with γT and leptin. To determine whether vitamin D(3) supplementation alters levels of lipid-soluble micronutrients, serum samples (N = 85 subjects) from a randomized, double-blind, placebo-controlled clinical trial of vitamin D(3) (800 IU) and calcium (2 g), alone and in combination, were analyzed for lipid micronutrients and specific vitamin D metabolites at baseline and after 6 mo of supplementation. Serum 25[OH]-vitamin D(3) levels increased 55% (P < 0.0001) and 48% (P = 0.0005), whereas 25[OH]-vitamin D(2) levels were lower by 48% (P = 0.26) and 21% (P = 0.36) in the vitamin D(3) and vitamin D(3) plus calcium groups, respectively. At baseline, γT levels were inversely associated with 25[OH]D (r = -0.31, P = 0.004). With vitamin D(3) plus calcium treatment, serum α-tocopherol decreased 14% (P = 0.04), whereas similar changes in γT (19% lower, P = 0.14) were observed. No significant effects were observed for D(3) supplementation on leptin or retinol levels. These results are consistent with the hypothesis that vitamin D(3) ± calcium affects serum tocopherol and 25[OH]D(2) levels; however, studies using larger, more homogeneous populations are warranted.

Urinary polyphenols, glutathione S-transferases copy number variation, and breast cancer risk: results from the Shanghai women's health study.

In vitro studies have found that flavanol epigallocatechin (EGC) and flavonols, but not flavanol epicatechin (EC), activate glutathione S-transferases (GSTs), a family of phase II enzymes that detoxify reactive oxygen species, such as catechol estrogen metabolites. This study was designed to investigate prospectively whether urinary excretion of tea polyphenols interacts with GST polymorphisms to influence breast cancer risk. We conducted a study of 352 incident breast cancer cases and 701 individually matched controls nested within the Shanghai Women's Health Study cohort of women aged 40-70 yr at baseline. Liquid chromatography tandem mass spectrometry was used to measure urinary excretion of flavanols and flavonols. Real-time multiplex PCR was used to quantify the copy number variation in the GSTM1 and GSTT1 genes. Urinary excretion of flavonols and flavanols, particularly EGC (P = 0.02), was significantly higher among women null for GSTM1 than those positive for GSTM1. Flavonols and flavanols (EGC in particular) were associated with a reduced risk of breast cancer among those null for GSTM1 and GSTT1, with a P-value of 0.04 for the interaction between EGC and GSTM1 polymorphism. In contrast, among women possessing both GSTM1 and GSTT1, breast cancer risk increased with levels of flavonols, particularly kaempferol. The differential associations between polyphenols and breast cancer risk by GST polymorphisms, if confirmed, may provide a new avenue for the personalized prevention of breast cancer.

Isoflavone soy protein supplementation and atherosclerosis progression in healthy postmenopausal women: a randomized controlled trial.

BACKGROUND AND PURPOSE: Although epidemiological and experimental studies suggest that dietary intake of soy may be cardioprotective, use of isoflavone soy protein (ISP) supplementation as a primary preventive therapy remains unexplored. We determined whether ISP reduces subclinical atherosclerosis assessed as carotid artery intima-media thickness progression. METHODS: In a double-blind, placebo-controlled trial, 350 postmenopausal women 45 to 92 years of age without diabetes and cardiovascular disease were randomized to 2 evenly divided daily doses of 25 g soy protein containing 91 mg aglycon isoflavone equivalents or placebo for 2.7 years. RESULTS: Overall, mean (95% CI) carotid artery intima-media thickness progression rate was 4.77 (3.39-6.16) µm/year in the ISP group and 5.68 (4.30-7.06) µm/year in the placebo group. Although carotid artery intima-media thickness progression was reduced on average by 16% in the ISP group relative to the placebo group, this treatment effect was not statistically significant (P=0.36). Among the subgroup of women who were randomized within 5 years of menopause, ISP participants had on average a 68% lower carotid artery intima-media thickness progression rate than placebo participants 2.16 (-1.10 to 5.43) versus 6.79 (3.56-10.01) µm/year (P=0.05). ISP supplementation had a null effect on women who were >5 years beyond menopause when randomized. There were no major adverse events from ISP supplementation. CONCLUSIONS: ISP supplementation did not significantly reduce subclinical atherosclerosis progression in postmenopausal women. Subgroup analysis suggests that ISP supplementation may reduce subclinical atherosclerosis in healthy young (median age, 53 years) women at low-risk for cardiovascular disease who were <5 years postmenopausal. These first trial results of their kind warrant further investigation.

Urinary polyphenols and breast cancer risk: results from the Shanghai Women's Health Study.

Polyphenols, the most abundant dietary antioxidants, also possess many other anticarcinogenic activities. Urinary metabolites of polyphenols could complement dietary assessment of the bioavailability of these nutrients. We conducted a study of 353 incident breast cancer cases and 701 individually matched controls nested within the Shanghai Women's Health Study cohort of women aged 40-70 years at baseline. Liquid chromatography photo-diode array electrospray mass spectrometry was used to measure tea polyphenols (epicatechin, epigallocatechin, and their metabolites) and flavonols (e.g., quercetin and kaempferol). Multivariate conditional logistic regression analyses were used to assess associations between breast cancer risk and urinary excretion rates of polyphenols. Urinary excretion of tea polyphenols increased with increasing tea leaves consumed among controls, but not among breast cancer cases. Compared with cases, controls had higher levels of urinary total polyphenols and tea polyphenols, particularly epicatechin. In contrast, we did not find any dose-response relationship between urinary polyphenols and breast cancer risk. Urinary excretion of epicatechin was inversely associated with breast cancer risk [odds ratio (OR) and 95% confidence interval (CI) of 0.59 (0.39-0.88) for the intermediate tertile]. In spline regression, we found an overall dose-response relationship between epicatechin level and risk of breast cancer, although it was not apparent in low and middle urinary excretion range. In conclusion, high epicatechin may be related to a reduced risk of breast cancer. Further studies are warranted to confirm our findings.

Urinary phytoestrogen excretion and postmenopausal breast cancer risk: the multiethnic cohort study.

The objective of this study was to examine the association of urinary phytoestrogens with the risk of postmenopausal breast cancer. Participants in the Multiethnic Cohort Study included 36,458 postmenopausal women who provided blood or urine specimens. A nested case-control study of breast cancer with biospecimens was created in which cases diagnosed after specimen collection were matched to two controls. Two hundred fifty-one women with breast cancer and 462 controls had urine available for analysis of urinary phytoestrogens. Odds ratios (OR) and 95% confidence intervals (CI) were obtained using conditional logistic regression. A nonmonotonic inverse trend (P = 0.04) in breast cancer risk was associated with increasing urinary excretion of genistein (OR 25th-75th percentile, 0.88; 95% CI, 0.78-0.99) and total isoflavones (OR 25th-75th percentile, 0.80; 95% CI, 0.65-0.99). A significant reduction in breast cancer risk in Japanese-American women was associated with the highest compared with the lowest quartile excretion of urinary daidzein (OR, 0.41; 95% CI, 0.19-0.89; P(trend), 0.005). The risk of breast cancer was reduced among White women with the highest compared with the lowest quartile excretion of equol (OR, 0.27; 95% CI, 0.08-0.95), although the trend in risk was not significant (P = 0.07). Our results provide some support to the hypothesis that a diet rich in isoflavones from soy products reduces the risk of postmenopausal breast cancer, particularly in populations with comparatively high excretion of phytoestrogens.

Association of plasma micronutrient levels and urinary isoprostane with risk of lung cancer: the multiethnic cohort study.

Although smoking is the primary risk factor for lung cancer, there is evidence to suggest that fruit and vegetable intake are important cofactors. The present case-control study, nested within the Multiethnic Cohort Study, examined the associations of biomarkers of fruit and vegetable intake (individual plasma micronutrient levels), serum selenium, and a urinary biomarker for total lipid peroxidation with lung cancer risk. Two hundred seven incident cases were matched to 414 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection, and hours of fasting. We measured prediagnositic circulating levels of individual tocopherols and carotenoids, retinol, and serum selenium, and urinary 15-isoprostane F(2t). Conditional logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI). For men, strong reductions in risk were seen with increasing tertiles of each plasma carotenoid, with the ORs for the third tertile, compared with the first tertile, ranging from 0.24 to 0.45 (P(trends), 0.002-0.04). No associations were found among women for carotenoids or among either sex for tocopherols, selenium, and retinol. A doubling in risk was seen for men in the second and third tertiles, compared with the first tertile of urinary 15-isoprostane F(2t) (OR, 2.31; 95% CI, 1.02-5.25; and OR, 2.16; 95% CI, 0.98-4.78). This study supports the previously observed association between circulating carotenoids and lung cancer risk in men, and adds to the limited literature regarding urinary 15-isoprostane F(2t) as a marker of cancer risk. Future research examining the possible relationship between isoprostanes and lung cancer is warranted.

Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women.

Seaweed and soy foods are consumed daily in Japan, where breast cancer rates for postmenopausal women are significantly lower than in the West. Likely mechanisms include differences in diet, especially soy consumption, and estrogen metabolism. Fifteen healthy postmenopausal women participated in this double-blind trial of seaweed supplementation with soy challenge. Participants were randomized to 7 wk of either 5 g/d seaweed (Alaria) or placebo (maltodextrin). During wk 7, participants also consumed a daily soy protein isolate (2 mg isoflavones/kg body weight). After a 3-wk washout period, participants were crossed over to the alternate supplement schedule. There was an inverse correlation between seaweed dose (mg/kg body weight) and serum estradiol (E2) (seaweed-placebo = y = -2.29 x dose + 172.3; r = -0.70; P = 0.003), [corrected] which was linear across the range of weights. Soy supplementation increased urinary daidzein, glycitein, genistein, and O-desmethylangolensin (P = 0.0001) and decreased matairesinol and enterolactone (P < 0.05). Soy and seaweed plus soy (SeaSoy) increased urinary excretion of 2-hydroxyestrogen (2-OHE) (P = 0.0001) and the ratio of 2-OHE:16alpha-hydroxyestrone (16alphaOHE(1)) (P = 0.01). For the 5 equol excretors, soy increased urinary equol excretion (P = 0.0001); the combination of SeaSoy further increased equol excretion by 58% (P = 0.0001). Equol producers also had a 315% increase in 2:16 ratio (P = 0.001) with SeaSoy. Seaweed favorably alters estrogen and phytoestrogen metabolism and these changes likely include modulation of colonic bacteria.

Association of selenium, tocopherols, carotenoids, retinol, and 15-isoprostane F(2t) in serum or urine with prostate cancer risk: the multiethnic cohort.

OBJECTIVE: We examine the association of antioxidants and 15-isoprostane F(2t) with risk of prostate cancer. METHODS: We conducted a nested case-control study of serum antioxidant biomarkers (selenium, tocopherols, carotenoids, and retinol) and a urinary oxidation biomarker (15-isoprostane F(2t)) with risk of prostate cancer within the Multiethnic Cohort. Demographic, dietary, and other exposure information was collected by self-administered questionnaire in 1993-1996. We compared prediagnostic biomarker levels from 467 prostate cancer cases and 936 cancer free controls that were matched on several variables. Multivariate conditional logistic regression models were used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We observed that there was no overall association of serum concentrations of antioxidants and urinary concentrations of 15-isoprostane F(2t) with risk of prostate cancer or risk of advanced prostate cancer. However, we did observe an inverse association for serum selenium only among African-American men (p trend = 0.02); men in the third tertile of selenium concentrations had a 41% lower risk (95% CI: 0.38-0.93) of prostate cancer when compared to men in the first tertile. CONCLUSIONS: Overall, our study found no association of serum antioxidants or 15-isoprostane F(2t) with the risk of prostate cancer. The observed inverse association of selenium with prostate cancer in African-Americans needs to be validated in other studies.