Mindy Kurzer | University of Minnesota - Twin Cities (original) (raw)
Papers by Mindy Kurzer
Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test... more Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test this hypothesis, we studied the effects of three soy powders containing different levels of isoflavones in 18 postmenopausal women. Isoflavones were consumed relative to body weight (control: 0.11 6 0.01; low isoflavone (low-iso): 1.00 6 0.01; high isoflavone (high-iso): 2.00 6 0.02 mg/kg/day) for 93 days
Atherosclerosis Supplements, 2010
The American journal of clinical nutrition, 1994
Midfollicular and midluteal dietary intakes of 18 women were evaluated between four and six ovula... more Midfollicular and midluteal dietary intakes of 18 women were evaluated between four and six ovulatory menstrual cycles. Phase lengths were established by basal body temperatures and urinary luteinizing hormone excretion. Midfollicular and midluteal diet records were collected 6-8 d after menstrual onset and 6-8 d after ovulation, respectively. Significant increases in energy [0.66 MJ (159 kcal), P = 0.003], protein (6.1 g, P = 0.02), carbohydrate (15.3 g, P = 0.04), and fat (8.6 g, P = 0.002) intakes were observed in midluteal phase when compared with midfollicular phase. Intakes of vitamin D, riboflavin, potassium, phosphorus, and magnesium also were significantly higher during midluteal phase (P < 0.05). These results support the regulation of food intake by menstrual cycle hormones and suggest that it is essential to consider phase of menstrual cycle in studies of nutrient intake performed in premenopausal women.
Objective: Examine interactive effects of life events, perceived stress and depressive symptoms d... more Objective: Examine interactive effects of life events, perceived stress and depressive symptoms during a randomized controlled aerobics intervention among women (aged 18e30) in the urban U.S. Midwest, 2006e2009. Method: Participants [n ¼ 372 at baseline and n ¼ 303 at follow-up] completed perceived stress, depressive symptoms and life events scales at baseline and 5e6 month follow-up. Life events were correlated with perceived stress and depressive symptoms scales using Pearson correlation. Multivariate linear regression tested the relationship between the 20 most common life events with perceived stress and depressive symptoms. Regression models explored relationships between life events, perceived stress and depressive symptoms and the intervention effect. Results: Higher levels of perceived stress and depressive symptoms correlated with more life events. At baseline, for every additional life event, depressive symptoms were higher; follow-up showed marginal significance with depressive symptoms, but a strong positive association with perceived stress. In the stratified model, for every life event at follow up, the perceived stress scale increased by 0.68 in the exercise group, but not in the controls. For every life event at follow-up, depressive symptoms were higher in controls, but not in the exercise group. Conclusion: Perceived stress and depressive symptoms co-occurred with life events at baseline and follow-up for participants. At follow up, perceived stress increased significantly among exercisers; depressive symptoms were significantly higher among controls. Findings suggest that new participation in structured physical activity entails a change in daily life that may buffer against depressive symptoms in relation to life events but not perceived stress.
The Journal of nutrition, 2004
Numerous studies report that soy lowers cholesterol. Probiotic bacteria were also reported to low... more Numerous studies report that soy lowers cholesterol. Probiotic bacteria were also reported to lower total cholesterol (TC) and LDL cholesterol (LDL-C). We hypothesized that by altering intestinal microflora, probiotic consumption may also change phytoestrogen metabolism and enhance the effects of soy. To evaluate the independent and interactive effects of probiotic bacteria and soy on plasma TC, LDL-C, HDL cholesterol (HDL-C), and triglycerides (TG), 37 women with a baseline TC of 5.24 mmol/L were given the following 4 treatments for 6 wk each in a randomized crossover design: soy protein isolate (26 +/- 5 g soy protein containing 44 +/- 8 mg isoflavones/d); soy protein isolate + probiotic capsules (10(9) colony-forming units Lactobacillus acidophilus DDS-1 and Bifidobacterium longum); milk protein isolate (26 +/- 5 g milk protein/d); and milk protein isolate + probiotic. Soy consumption decreased plasma TC by 2.2% (P = 0.02) and LDL-C by 3.5% (P = 0.005), increased HDL-C by 4.2% (P...
The Journal of nutrition, 2005
Some epidemiologic studies reported an association between a low ratio of urinary 2-hydroxyestrog... more Some epidemiologic studies reported an association between a low ratio of urinary 2-hydroxyestrogens (2-hydroxyestradiol + 2-hydroxyestrone) to 16alpha-hydroxyestrone (2:16OHE(1)) and increased breast cancer risk. Some studies show that soy consumption increases this ratio, and it is suggested that this effect may reduce breast cancer risk. We hypothesized that consumption of probiotic bacteria would alter fecal bacteria and enzymes involved in soy isoflavone metabolism, thereby increasing isoflavone bioavailability and enhancing the beneficial effects of soy on estrogen metabolism. Breast cancer survivors (n = 20) and controls (n = 20) were given 4 treatments for 6 wk each, separated by 2-wk washout periods, in a randomized, crossover design: soy protein (26.6 +/- 4.5 g protein/d containing 44.4 +/- 7.5 mg isoflavones/d); soy protein + probiotics (10(9) colony-forming units Lactobacillus acidophilus DDS(R)+1 & Bifidobacterium longum, 15-30 mg fructooligosaccharide/d); milk protein ...
The Journal of nutrition, 2007
The purpose of this study was to determine the effects of soy protein isolate consumption on circ... more The purpose of this study was to determine the effects of soy protein isolate consumption on circulating hormone profiles and hormone receptor expression patterns in men at high risk for developing advanced prostate cancer. Fifty-eight men were randomly assigned to consume 1 of 3 protein isolates containing 40 g/d protein: 1) soy protein isolate (SPI+) (107 mg/d isoflavones); 2) alcohol-washed soy protein isolate (SPI-) (<6 mg/d isoflavones); or 3) milk protein isolate (0 mg/d isoflavones). For 6 mo, the men consumed the protein isolates in divided doses twice daily as a partial meal replacement. Serum samples collected at 0, 3, and 6 mo were analyzed for circulating estradiol, estrone, sex hormone-binding globulin, androstenedione, androstanediol glucuronide, dehydroepiandrosterone sulfate, dihydrotestosterone, testosterone, and free testosterone concentrations by RIA. Prostate biopsy samples obtained pre- and postintervention were analyzed for androgen receptor (AR) and estroge...
The Journal of nutrition, 2004
Soy phytoestrogens were suggested to reduce the risk of a number of diseases including breast can... more Soy phytoestrogens were suggested to reduce the risk of a number of diseases including breast cancer. Given that these compounds are metabolized by bacteria, alteration of intestinal bacteria and enzymes may affect phytoestrogen metabolism. We hypothesized that probiotics, when consumed with soy protein, would increase plasma isoflavones, as well as equol producer frequency, in postmenopausal women. We further hypothesized that these effects would differ between women who have had breast cancer and women who have not. To test these hypotheses, 20 breast cancer survivors and 20 controls completed four 6-wk treatments in a randomized, crossover design: supplementation with soy protein (S) (26.6 +/- 4.5 g protein, 44.4 +/- 7.5 mg isoflavones/d); soy + probiotics (S+P) (10(9) colony-forming units Lactobacillus acidophilus DDS+1 and Bifidobacterium longum, 15-30 mg fructooligosaccharide/d); milk protein (M) (26.6 +/- 4.5 g protein/d); and milk + probiotics (M+P). Plasma phytoestrogen con...
Nutrition Research, 2015
Research studies have suggested that chronic consumption of high glycemic index foods may lead to... more Research studies have suggested that chronic consumption of high glycemic index foods may lead to chronically high oxidative stress. This is important because oxidative stress is suspected to be an early event in the etiology of many disease processes. We hypothesized that dietary glycemic index and glycemic load were positively associated with oxidative stress assessed by plasma F2-isoprostanes in healthy, premenopausal women (body mass index [BMI] = 24.7 ± 4.8 kg/m(2) and age 25.3 ± 3.5 years, mean ± SD). We measured plasma F2-isoprostanes in 306 healthy premenopausal women at the baseline visit for the Women In Steady Exercise Research study, using gas chromatography-mass spectrometry. Dietary glycemic index and load were calculated from the National Cancer Institute Diet History Questionnaire, and participants were divided into quartiles of dietary glycemic index and of glycemic load. Plasma F2-isoprostanes were compared across quartile groups of dietary glycemic index and glycemic load using linear regression models. Plasma F2-isoprostanes (pg/mL) increased with quartile of glycemic load (test for linear trend, P = .033), and also increased with quartile of glycemic index in participants with BMI ≥ 25 (P = .035) but not in those with BMI &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;25 (P = .924). After adjustment for BMI, alcohol consumption and total energy intake, both these positive trends remained marginally significant (P = .123 for quartiles of glycemic index and P = .065 for quartiles of glycemic load).
Nutrition and Cancer-an International Journal, 2011
Higher levels of insulin and insulin-like growth factor 1 (IGF-1) increase cancer risk by stimula... more Higher levels of insulin and insulin-like growth factor 1 (IGF-1) increase cancer risk by stimulating cell proliferation and increasing survival of DNA-damaged cells through antiapoptotic mechanisms. Laboratory studies suggest that flaxseed added to the diet may lower circulating levels of insulin and IGF-1, but there is limited information on the effects of dietary flaxseed on these biomarkers of cancer risk
Background: Total fat and omega-3 fatty acids in the diet may affect breast cancer risk by alteri... more Background: Total fat and omega-3 fatty acids in the diet may affect breast cancer risk by altering estrogen metabolism. The purpose of this study was to elucidate the effects of differing total fat and omega-3 fatty acid content of diets on a panel of urinary estrogens and metabolites. Findings: A controlled, cross-over feeding trial was conducted in postmenopausal women using three test diets: high fat diet (HF; 40% energy from fat), low fat diet (LF; 20% of energy from fat) and low fat, high omega-3 diet (LFn3; 23% energy from fat; 3% omega-3 fatty acids) for 8 week periods. Urinary hormone concentrations for 16 women were compared among diets using a linear mixed model, and within diet comparisons were made using paired t-tests. Urinary excretion of estrone was greater after the LF and LFn3 compared to the HF (P = 0.004). Estrone excretion was increased from baseline within the LF only (P = 0.02). Total estrone + estradiol + estriol increased from baseline with LF (P = 0.02) and was greater than the other two diets at 8 weeks (P = 0.03). There were no effects on estrogen metabolites, including the 2-hydroxy estrone:16α-hydroxy estrone ratio. Conclusions: The results of this study indicate that urinary sex hormone metabolism was modestly altered in postmenopausal women by a low fat dietary intervention.
Contemporary clinical trials, Jan 3, 2015
Women at elevated risk for breast cancer are motivated to reduce their risk. Current approaches r... more Women at elevated risk for breast cancer are motivated to reduce their risk. Current approaches rely primarily on hormonal intervention. A preventive exercise intervention might address the same hormonal issues, yet have fewer serious side effects and less negative impact on quality of life as compared to prophylactic mastectomy. WISER Sister was a randomized controlled trial which examined effects of two doses of exercise training on endogenous sex hormone exposure, hormonally active breast tissue, and other breast cancer risk factors. Subjects for this single site trial were recruited from across the U.S., in collaboration with organizations that serve women at elevated risk, via emails, flyers, and letters. Eligibility criteria included age ≥18, eumenorrheic, and at elevated risk for breast cancer (e.g. BRCA1 or BRCA2 mutation and/or ≥18% lifetime risk according to prediction models). A 1:1:1 randomization scheme was used to allocate participants into: control, low dose (150min/w...
Obstetrics & Gynecology, 1998
We assessed changes in creatinine clearance during the menstrual cycle of normally cycling women.
Nutrition Research, 2013
The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of ... more The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of tissues; however, nutritional determinants of insulin-like growth factor I (IGF-I) and its binding proteins in healthy individuals are not well defined. Three test diets-high-fat diet (40% energy as fat), low-fat diet (LF; 20% energy as fat), and a diet with low fat and high omega-3 fatty acid (LFn3; 23% energy as fat)--were tested in a randomized crossover designed controlled feeding trial in healthy postmenopausal women. Plasma IGF-I, IGF binding protein-3 (IGFBP-3), insulin, glucose, and ratio of IGF-I/IGFBP-3 concentrations were measured in response to diets. Insulin sensitivity was calculated using the homeostatic model assessment of insulin resistance We hypothesized that IGF-I, insulin, and glucose concentrations would decrease and IGFBP-3 concentration would increase in response to the low-fat diets. Eight weeks of the LFn3 diet increased circulating IGF-I (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) and IGFBP-3 (P = .01) and the LF diet increased IGFBP-3 (P = .04), resulting in trends toward an increased IGF-I/IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I/IGFBP-3 ratio with the LF diet (P = .13 for both comparisons). No statistically significant differences were detected between treatments at baseline or 8 weeks for IGF-1, IGFBP-3, or the ratio of IGF-1/IGFBP-3. Insulin, glucose, and the homeostatic model assessment of insulin resistance were not altered by the interventions. Low-fat diet with high n-3 fatty acids may increase circulating IGF-I concentrations without adversely affecting insulin sensitivity in healthy individuals.
Nutrition Research, 2003
This paper presents the in vivo antioxidant activity of soy isoflavones in human subjects determi... more This paper presents the in vivo antioxidant activity of soy isoflavones in human subjects determined by the urinary excretion of secondary lipid peroxidation products. Ten healthy women 18-35 years of age consumed a self-selected diet and avoided legumes, whole grains, and isoflavone containing foods. A powdered soy protein isolate was added daily to their diet that provided 3 levels of isoflavones: control 0.15, low 1.01, and high 2.01 mg/kg body weight. Subjects were randomized to consume all three diets for 13 weeks each, with each subject serving as her own control. Urine samples were analyzed from 24-hr collections at the end of each diet period for lipophilic aldehydes and related carbonyl compounds by HPLC. Results show that six of the individual urinary nonpolar compounds (NPC) levels were significantly lower due to consumption of the high isoflavone diet and one was also significantly lower due to consumption of the low isoflavone diet. The total of the individually measured urinary NPC was significantly lower with consumption of both the low and high isoflavone diets when compared with the control diet.
Nutrition and Cancer, 2011
Substantial evidence relates increased sex hormone concentrations with increased breast cancer ri... more Substantial evidence relates increased sex hormone concentrations with increased breast cancer risk. Varying omega-3 (n-3) fatty acid (FA) intake may lead to alterations in eicosanoid balance and changes in circulating sex hormones that reduce risk. To clarify effects of dietary fat and n-3 FA intake on breast cancer risk markers, circulating sex hormones and urinary eicosanoids were measured in response to controlled feeding of diets designed to increase plasma concentrations of n-3 FA. A controlled cross-over feeding trial in postmenopausal women was conducted using 3 diets: high fat (HF; 40% energy from fat), low fat (LF; 20% energy from fat), and low fat plus n-3 FA (LFn3; 20% of energy from fat plus 3% of energy from n-3 FA) in 8-wk feeding periods. Plasma phospholipid fatty acid n-3 increased with the LFn3 relative to HF and LF (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). Plasma estradiol increased by 51% with HF (P = 0.03). Urinary prostaglandin E metabolite increased with HF relative to LF (P = 0.02) and urinary 11-dehydro-thromboxane B(2) increased with HF (P = 0.01). These results do not support a role of n-3 FA in the reduction of sex hormone levels.
Nutrition and Cancer, 2008
Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert brea... more Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert breast cancer preventive effects through hormonal mechanisms. Our aim was to study the effects of flaxseed on serum sex hormones implicated in the development of breast cancer. Forty-eight postmenopausal women participated in a 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for the first 6 wk and 15.0 grams/day for an additional 6 wk. Nonsignificant declines were noted over the 12 wk (95% confidence intervals) for estradiol (pg/ml), estrone (pg/ml), and testosterone (pg/ml): -4.4 (-12.6 to 3.9), -3.3 (-7.7 to 1.2), -4.7 (-17.8 to 8.5), respectively. Changes tended to be more pronounced in overweight/obese women, particularly for estrone (-6.5, -11.9 to -1.2; P = .02). Our results suggest that dietary flaxseed may modestly lower serum levels of sex steroid hormones, especially in overweight/obese women.
Nutrition and Cancer, 2008
Data regarding convenient, valid methods for measuring U.S. isoflavone intake are limited. We eva... more Data regarding convenient, valid methods for measuring U.S. isoflavone intake are limited. We evaluated a soy food questionnaire (SFQ), the Willett food frequency questionnaire (FFQ), and overnight urine samples relative to excretion in 24-h urine samples. We also described intake among women in a high-risk program for breast or ovarian cancer. Between April 2002 and June 2003, 451 women aged 30 to 50 yr with a family history of breast or ovarian cancer completed the SFQ and FFQ. Of them, 27 provided four 24-h and overnight urine specimens. In these women, 24-h sample measures were correlated with SFQ estimates of daidzein (Spearman r = .48) and genistein (r = .54) intake, moderately correlated with the Willett FFQ (daidzein r = .38, genistein r = .33), and strongly correlated with overnight urine excretion (daidzein r = .84, genistein r = 0.93). Among all 451 SFQ respondents, mean (median) daidzein and genistein intakes were 2.8 (0.24) and 3.9 (0.30) mg/day. Primary sources of both were soymilk, soy nuts, and tofu. We conclude that targeted soy food questionnaires, com-prehensive FFQs, and multiple overnight urines are all reasonable options for assessing isoflavone intake in epidemiologic studies.
Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test... more Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test this hypothesis, we studied the effects of three soy powders containing different levels of isoflavones in 18 postmenopausal women. Isoflavones were consumed relative to body weight (control: 0.11 6 0.01; low isoflavone (low-iso): 1.00 6 0.01; high isoflavone (high-iso): 2.00 6 0.02 mg/kg/day) for 93 days
Atherosclerosis Supplements, 2010
The American journal of clinical nutrition, 1994
Midfollicular and midluteal dietary intakes of 18 women were evaluated between four and six ovula... more Midfollicular and midluteal dietary intakes of 18 women were evaluated between four and six ovulatory menstrual cycles. Phase lengths were established by basal body temperatures and urinary luteinizing hormone excretion. Midfollicular and midluteal diet records were collected 6-8 d after menstrual onset and 6-8 d after ovulation, respectively. Significant increases in energy [0.66 MJ (159 kcal), P = 0.003], protein (6.1 g, P = 0.02), carbohydrate (15.3 g, P = 0.04), and fat (8.6 g, P = 0.002) intakes were observed in midluteal phase when compared with midfollicular phase. Intakes of vitamin D, riboflavin, potassium, phosphorus, and magnesium also were significantly higher during midluteal phase (P < 0.05). These results support the regulation of food intake by menstrual cycle hormones and suggest that it is essential to consider phase of menstrual cycle in studies of nutrient intake performed in premenopausal women.
Objective: Examine interactive effects of life events, perceived stress and depressive symptoms d... more Objective: Examine interactive effects of life events, perceived stress and depressive symptoms during a randomized controlled aerobics intervention among women (aged 18e30) in the urban U.S. Midwest, 2006e2009. Method: Participants [n ¼ 372 at baseline and n ¼ 303 at follow-up] completed perceived stress, depressive symptoms and life events scales at baseline and 5e6 month follow-up. Life events were correlated with perceived stress and depressive symptoms scales using Pearson correlation. Multivariate linear regression tested the relationship between the 20 most common life events with perceived stress and depressive symptoms. Regression models explored relationships between life events, perceived stress and depressive symptoms and the intervention effect. Results: Higher levels of perceived stress and depressive symptoms correlated with more life events. At baseline, for every additional life event, depressive symptoms were higher; follow-up showed marginal significance with depressive symptoms, but a strong positive association with perceived stress. In the stratified model, for every life event at follow up, the perceived stress scale increased by 0.68 in the exercise group, but not in the controls. For every life event at follow-up, depressive symptoms were higher in controls, but not in the exercise group. Conclusion: Perceived stress and depressive symptoms co-occurred with life events at baseline and follow-up for participants. At follow up, perceived stress increased significantly among exercisers; depressive symptoms were significantly higher among controls. Findings suggest that new participation in structured physical activity entails a change in daily life that may buffer against depressive symptoms in relation to life events but not perceived stress.
The Journal of nutrition, 2004
Numerous studies report that soy lowers cholesterol. Probiotic bacteria were also reported to low... more Numerous studies report that soy lowers cholesterol. Probiotic bacteria were also reported to lower total cholesterol (TC) and LDL cholesterol (LDL-C). We hypothesized that by altering intestinal microflora, probiotic consumption may also change phytoestrogen metabolism and enhance the effects of soy. To evaluate the independent and interactive effects of probiotic bacteria and soy on plasma TC, LDL-C, HDL cholesterol (HDL-C), and triglycerides (TG), 37 women with a baseline TC of 5.24 mmol/L were given the following 4 treatments for 6 wk each in a randomized crossover design: soy protein isolate (26 +/- 5 g soy protein containing 44 +/- 8 mg isoflavones/d); soy protein isolate + probiotic capsules (10(9) colony-forming units Lactobacillus acidophilus DDS-1 and Bifidobacterium longum); milk protein isolate (26 +/- 5 g milk protein/d); and milk protein isolate + probiotic. Soy consumption decreased plasma TC by 2.2% (P = 0.02) and LDL-C by 3.5% (P = 0.005), increased HDL-C by 4.2% (P...
The Journal of nutrition, 2005
Some epidemiologic studies reported an association between a low ratio of urinary 2-hydroxyestrog... more Some epidemiologic studies reported an association between a low ratio of urinary 2-hydroxyestrogens (2-hydroxyestradiol + 2-hydroxyestrone) to 16alpha-hydroxyestrone (2:16OHE(1)) and increased breast cancer risk. Some studies show that soy consumption increases this ratio, and it is suggested that this effect may reduce breast cancer risk. We hypothesized that consumption of probiotic bacteria would alter fecal bacteria and enzymes involved in soy isoflavone metabolism, thereby increasing isoflavone bioavailability and enhancing the beneficial effects of soy on estrogen metabolism. Breast cancer survivors (n = 20) and controls (n = 20) were given 4 treatments for 6 wk each, separated by 2-wk washout periods, in a randomized, crossover design: soy protein (26.6 +/- 4.5 g protein/d containing 44.4 +/- 7.5 mg isoflavones/d); soy protein + probiotics (10(9) colony-forming units Lactobacillus acidophilus DDS(R)+1 & Bifidobacterium longum, 15-30 mg fructooligosaccharide/d); milk protein ...
The Journal of nutrition, 2007
The purpose of this study was to determine the effects of soy protein isolate consumption on circ... more The purpose of this study was to determine the effects of soy protein isolate consumption on circulating hormone profiles and hormone receptor expression patterns in men at high risk for developing advanced prostate cancer. Fifty-eight men were randomly assigned to consume 1 of 3 protein isolates containing 40 g/d protein: 1) soy protein isolate (SPI+) (107 mg/d isoflavones); 2) alcohol-washed soy protein isolate (SPI-) (<6 mg/d isoflavones); or 3) milk protein isolate (0 mg/d isoflavones). For 6 mo, the men consumed the protein isolates in divided doses twice daily as a partial meal replacement. Serum samples collected at 0, 3, and 6 mo were analyzed for circulating estradiol, estrone, sex hormone-binding globulin, androstenedione, androstanediol glucuronide, dehydroepiandrosterone sulfate, dihydrotestosterone, testosterone, and free testosterone concentrations by RIA. Prostate biopsy samples obtained pre- and postintervention were analyzed for androgen receptor (AR) and estroge...
The Journal of nutrition, 2004
Soy phytoestrogens were suggested to reduce the risk of a number of diseases including breast can... more Soy phytoestrogens were suggested to reduce the risk of a number of diseases including breast cancer. Given that these compounds are metabolized by bacteria, alteration of intestinal bacteria and enzymes may affect phytoestrogen metabolism. We hypothesized that probiotics, when consumed with soy protein, would increase plasma isoflavones, as well as equol producer frequency, in postmenopausal women. We further hypothesized that these effects would differ between women who have had breast cancer and women who have not. To test these hypotheses, 20 breast cancer survivors and 20 controls completed four 6-wk treatments in a randomized, crossover design: supplementation with soy protein (S) (26.6 +/- 4.5 g protein, 44.4 +/- 7.5 mg isoflavones/d); soy + probiotics (S+P) (10(9) colony-forming units Lactobacillus acidophilus DDS+1 and Bifidobacterium longum, 15-30 mg fructooligosaccharide/d); milk protein (M) (26.6 +/- 4.5 g protein/d); and milk + probiotics (M+P). Plasma phytoestrogen con...
Nutrition Research, 2015
Research studies have suggested that chronic consumption of high glycemic index foods may lead to... more Research studies have suggested that chronic consumption of high glycemic index foods may lead to chronically high oxidative stress. This is important because oxidative stress is suspected to be an early event in the etiology of many disease processes. We hypothesized that dietary glycemic index and glycemic load were positively associated with oxidative stress assessed by plasma F2-isoprostanes in healthy, premenopausal women (body mass index [BMI] = 24.7 ± 4.8 kg/m(2) and age 25.3 ± 3.5 years, mean ± SD). We measured plasma F2-isoprostanes in 306 healthy premenopausal women at the baseline visit for the Women In Steady Exercise Research study, using gas chromatography-mass spectrometry. Dietary glycemic index and load were calculated from the National Cancer Institute Diet History Questionnaire, and participants were divided into quartiles of dietary glycemic index and of glycemic load. Plasma F2-isoprostanes were compared across quartile groups of dietary glycemic index and glycemic load using linear regression models. Plasma F2-isoprostanes (pg/mL) increased with quartile of glycemic load (test for linear trend, P = .033), and also increased with quartile of glycemic index in participants with BMI ≥ 25 (P = .035) but not in those with BMI &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;25 (P = .924). After adjustment for BMI, alcohol consumption and total energy intake, both these positive trends remained marginally significant (P = .123 for quartiles of glycemic index and P = .065 for quartiles of glycemic load).
Nutrition and Cancer-an International Journal, 2011
Higher levels of insulin and insulin-like growth factor 1 (IGF-1) increase cancer risk by stimula... more Higher levels of insulin and insulin-like growth factor 1 (IGF-1) increase cancer risk by stimulating cell proliferation and increasing survival of DNA-damaged cells through antiapoptotic mechanisms. Laboratory studies suggest that flaxseed added to the diet may lower circulating levels of insulin and IGF-1, but there is limited information on the effects of dietary flaxseed on these biomarkers of cancer risk
Background: Total fat and omega-3 fatty acids in the diet may affect breast cancer risk by alteri... more Background: Total fat and omega-3 fatty acids in the diet may affect breast cancer risk by altering estrogen metabolism. The purpose of this study was to elucidate the effects of differing total fat and omega-3 fatty acid content of diets on a panel of urinary estrogens and metabolites. Findings: A controlled, cross-over feeding trial was conducted in postmenopausal women using three test diets: high fat diet (HF; 40% energy from fat), low fat diet (LF; 20% of energy from fat) and low fat, high omega-3 diet (LFn3; 23% energy from fat; 3% omega-3 fatty acids) for 8 week periods. Urinary hormone concentrations for 16 women were compared among diets using a linear mixed model, and within diet comparisons were made using paired t-tests. Urinary excretion of estrone was greater after the LF and LFn3 compared to the HF (P = 0.004). Estrone excretion was increased from baseline within the LF only (P = 0.02). Total estrone + estradiol + estriol increased from baseline with LF (P = 0.02) and was greater than the other two diets at 8 weeks (P = 0.03). There were no effects on estrogen metabolites, including the 2-hydroxy estrone:16α-hydroxy estrone ratio. Conclusions: The results of this study indicate that urinary sex hormone metabolism was modestly altered in postmenopausal women by a low fat dietary intervention.
Contemporary clinical trials, Jan 3, 2015
Women at elevated risk for breast cancer are motivated to reduce their risk. Current approaches r... more Women at elevated risk for breast cancer are motivated to reduce their risk. Current approaches rely primarily on hormonal intervention. A preventive exercise intervention might address the same hormonal issues, yet have fewer serious side effects and less negative impact on quality of life as compared to prophylactic mastectomy. WISER Sister was a randomized controlled trial which examined effects of two doses of exercise training on endogenous sex hormone exposure, hormonally active breast tissue, and other breast cancer risk factors. Subjects for this single site trial were recruited from across the U.S., in collaboration with organizations that serve women at elevated risk, via emails, flyers, and letters. Eligibility criteria included age ≥18, eumenorrheic, and at elevated risk for breast cancer (e.g. BRCA1 or BRCA2 mutation and/or ≥18% lifetime risk according to prediction models). A 1:1:1 randomization scheme was used to allocate participants into: control, low dose (150min/w...
Obstetrics & Gynecology, 1998
We assessed changes in creatinine clearance during the menstrual cycle of normally cycling women.
Nutrition Research, 2013
The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of ... more The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of tissues; however, nutritional determinants of insulin-like growth factor I (IGF-I) and its binding proteins in healthy individuals are not well defined. Three test diets-high-fat diet (40% energy as fat), low-fat diet (LF; 20% energy as fat), and a diet with low fat and high omega-3 fatty acid (LFn3; 23% energy as fat)--were tested in a randomized crossover designed controlled feeding trial in healthy postmenopausal women. Plasma IGF-I, IGF binding protein-3 (IGFBP-3), insulin, glucose, and ratio of IGF-I/IGFBP-3 concentrations were measured in response to diets. Insulin sensitivity was calculated using the homeostatic model assessment of insulin resistance We hypothesized that IGF-I, insulin, and glucose concentrations would decrease and IGFBP-3 concentration would increase in response to the low-fat diets. Eight weeks of the LFn3 diet increased circulating IGF-I (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) and IGFBP-3 (P = .01) and the LF diet increased IGFBP-3 (P = .04), resulting in trends toward an increased IGF-I/IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I/IGFBP-3 ratio with the LF diet (P = .13 for both comparisons). No statistically significant differences were detected between treatments at baseline or 8 weeks for IGF-1, IGFBP-3, or the ratio of IGF-1/IGFBP-3. Insulin, glucose, and the homeostatic model assessment of insulin resistance were not altered by the interventions. Low-fat diet with high n-3 fatty acids may increase circulating IGF-I concentrations without adversely affecting insulin sensitivity in healthy individuals.
Nutrition Research, 2003
This paper presents the in vivo antioxidant activity of soy isoflavones in human subjects determi... more This paper presents the in vivo antioxidant activity of soy isoflavones in human subjects determined by the urinary excretion of secondary lipid peroxidation products. Ten healthy women 18-35 years of age consumed a self-selected diet and avoided legumes, whole grains, and isoflavone containing foods. A powdered soy protein isolate was added daily to their diet that provided 3 levels of isoflavones: control 0.15, low 1.01, and high 2.01 mg/kg body weight. Subjects were randomized to consume all three diets for 13 weeks each, with each subject serving as her own control. Urine samples were analyzed from 24-hr collections at the end of each diet period for lipophilic aldehydes and related carbonyl compounds by HPLC. Results show that six of the individual urinary nonpolar compounds (NPC) levels were significantly lower due to consumption of the high isoflavone diet and one was also significantly lower due to consumption of the low isoflavone diet. The total of the individually measured urinary NPC was significantly lower with consumption of both the low and high isoflavone diets when compared with the control diet.
Nutrition and Cancer, 2011
Substantial evidence relates increased sex hormone concentrations with increased breast cancer ri... more Substantial evidence relates increased sex hormone concentrations with increased breast cancer risk. Varying omega-3 (n-3) fatty acid (FA) intake may lead to alterations in eicosanoid balance and changes in circulating sex hormones that reduce risk. To clarify effects of dietary fat and n-3 FA intake on breast cancer risk markers, circulating sex hormones and urinary eicosanoids were measured in response to controlled feeding of diets designed to increase plasma concentrations of n-3 FA. A controlled cross-over feeding trial in postmenopausal women was conducted using 3 diets: high fat (HF; 40% energy from fat), low fat (LF; 20% energy from fat), and low fat plus n-3 FA (LFn3; 20% of energy from fat plus 3% of energy from n-3 FA) in 8-wk feeding periods. Plasma phospholipid fatty acid n-3 increased with the LFn3 relative to HF and LF (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). Plasma estradiol increased by 51% with HF (P = 0.03). Urinary prostaglandin E metabolite increased with HF relative to LF (P = 0.02) and urinary 11-dehydro-thromboxane B(2) increased with HF (P = 0.01). These results do not support a role of n-3 FA in the reduction of sex hormone levels.
Nutrition and Cancer, 2008
Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert brea... more Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert breast cancer preventive effects through hormonal mechanisms. Our aim was to study the effects of flaxseed on serum sex hormones implicated in the development of breast cancer. Forty-eight postmenopausal women participated in a 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for the first 6 wk and 15.0 grams/day for an additional 6 wk. Nonsignificant declines were noted over the 12 wk (95% confidence intervals) for estradiol (pg/ml), estrone (pg/ml), and testosterone (pg/ml): -4.4 (-12.6 to 3.9), -3.3 (-7.7 to 1.2), -4.7 (-17.8 to 8.5), respectively. Changes tended to be more pronounced in overweight/obese women, particularly for estrone (-6.5, -11.9 to -1.2; P = .02). Our results suggest that dietary flaxseed may modestly lower serum levels of sex steroid hormones, especially in overweight/obese women.
Nutrition and Cancer, 2008
Data regarding convenient, valid methods for measuring U.S. isoflavone intake are limited. We eva... more Data regarding convenient, valid methods for measuring U.S. isoflavone intake are limited. We evaluated a soy food questionnaire (SFQ), the Willett food frequency questionnaire (FFQ), and overnight urine samples relative to excretion in 24-h urine samples. We also described intake among women in a high-risk program for breast or ovarian cancer. Between April 2002 and June 2003, 451 women aged 30 to 50 yr with a family history of breast or ovarian cancer completed the SFQ and FFQ. Of them, 27 provided four 24-h and overnight urine specimens. In these women, 24-h sample measures were correlated with SFQ estimates of daidzein (Spearman r = .48) and genistein (r = .54) intake, moderately correlated with the Willett FFQ (daidzein r = .38, genistein r = .33), and strongly correlated with overnight urine excretion (daidzein r = .84, genistein r = 0.93). Among all 451 SFQ respondents, mean (median) daidzein and genistein intakes were 2.8 (0.24) and 3.9 (0.30) mg/day. Primary sources of both were soymilk, soy nuts, and tofu. We conclude that targeted soy food questionnaires, com-prehensive FFQs, and multiple overnight urines are all reasonable options for assessing isoflavone intake in epidemiologic studies.