Biomedical subjects

Mindy S Kurzer

Publications and source records attributed to Mindy S Kurzer.

10 recordsLinked to original sources

PubMed2006

Consumption of Lactobacillus acidophilus and Bifidobacterium longum does not alter phytoestrogen metabolism and plasma hormones in men: a pilot study.

OBJECTIVE: The aim of this study was to determine whether equol excretion status and plasma hormone and leptin concentrations can be influenced by consumption of a probiotic supplement. A secondary focus was to investigate whether male equol excretors have a hormone profile consistent with reduced prostate cancer risk. DESIGN: The design was a randomized, single-blinded, placebo-controlled, parallel-arm trial. SUBJECTS: Thirty-one (31) of the initially enrolled 39 subjects, 18 to 37 years old, completed all study requirements. INTERVENTION: Subjects consumed either probiotic capsules (containing Lactobacillus acidophilus and Bifidobacterium longum) or placebo capsules for 2 months. Fasting plasma concentrations of testosterone (T), dihydrotestosterone (DHT), androstanediol glucuronide (AAG), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), and leptin were measured on days 1 and 57. Urinary excretion of genistein, glycitein, daidzein, O-desmethylangolensin (O-Dma), and equol was measured on days 4 and 61 following a 4-day soy challenge. RESULTS: Probiotic consumption did not significantly alter equol excretor status, plasma hormone, or leptin concentrations in these subjects. At baseline, there were no differences in plasma hormone concentrations between equol excretors and nonexcretors; however, the low number of equol excretors included in this study limits the strength of this finding. CONCLUSIONS: The 2-month intervention with probiotic capsules did not significantly alter equol excretion, plasma hormone, or leptin concentrations in these subjects. A secondary finding was that male equol excretors in this study did not exhibit a hormone profile consistent with reduced prostate cancer risk, although this result should be interpreted with caution.

Adrenal Cortex Hormones↗

PubMed2005

Short-term soy and probiotic supplementation does not markedly affect concentrations of reproductive hormones in postmenopausal women with and without histories of breast cancer.

BACKGROUND: Observational studies suggest that dietary isoflavones reduce breast cancer risk, and this may be caused in part by effects on endogenous hormone concentrations. Because intestinal bacteria metabolize isoflavones, it was hypothesized that consumption of probiotic bacteria would enhance the biologic effects of isoflavones, including effects on endogenous hormones. DESIGN: Twenty (20) postmenopausal breast cancer survivors and 20 healthy postmenopausal women completed four 42-day diet periods in a randomized, crossover design. They received one of the following: isolated soy protein; isolated milk protein; soy + probiotic capsules; or milk + probiotic capsules. Each protein supplement provided 0.38 g protein/(kg body weight/day) (26.6 +/- 4.5 g protein/day) and soy protein provided 0.64 mg isoflavones/(kg body weight/day) (44.4 +/- 7.5 mg isoflavones/day). Probiotic capsules provided 10(9) colony-forming units Lactobacillus acidophilus (strain DDS-1), Bifidobacterium longum, and 15-20 mg fructo-oligosaccharide. MEASURES: Plasma samples were collected at baseline and after each diet for analysis of estrogens, follicle-stimulating hormone (FSH), androgens, and sex hormone?binding globulin (SHBG). RESULTS: Hormone levels were not affected by soy, probiotic supplements, or equol producer status, and neither cancer status nor equol producer status altered the effects of soy or probiotics. Furthermore probiotics did not alter the effects of soy consumption. Soy protein tended to decrease SHBG compared to milk protein diets (p = 0.05), although both proteins significantly decreased SHBG relative to baseline (p = 0.0001 and p = 0.03). CONCLUSIONS: These data suggest that short-term, moderate consumption of isoflavone-containing soy protein and consumption of these particular probiotic capsules do not significantly alter reproductive hormone concentrations in breast cancer survivors or controls, regardless of equol producer status.

Administration, Oral↗

PubMed2005

The effect of soy consumption on the urinary 2:16-hydroxyestrone ratio in postmenopausal women depends on equol production status but is not influenced by probiotic consumption.

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 (26.6 +/- 4.5 g protein/d); and milk protein + probiotics. Survivors tended to have a lower baseline urine 2:16OHE(1) ratio than controls (P = 0.10). In the group as a whole, soy consumption tended to increase urinary 2-hydroxyestrogens (P = 0.07) and 16alpha-hydroxyestrone (P = 0.11) but had no effect on the urinary 2:16OHE(1) ratio. When subjects were divided into groups by plasma concentrations and urinary levels of the daidzein metabolite equol, soy increased urinary 2-hydroxyestrogens (P = 0.01) and the 2:16OHE(1) ratio (P = 0.04) only in subjects with high plasma equol concentrations. None of these results were influenced by probiotic consumption. These results are consistent with studies that found lower urine 2:16OHE(1) ratios in women with breast cancer and suggest that soy consumption increases this ratio only in women who are equol producers.

Bifidobacterium↗

PubMed2004

Probiotic consumption does not enhance the cholesterol-lowering effect of soy in postmenopausal women.

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 = 0.006) and tended to decrease TG (P = 0.07) compared with milk protein intake. When divided according to initial TC concentration, soy effects were observed only in hypercholesterolemic women (TC > 5.17 mmol/L). In this subgroup, soy treatments decreased plasma TC by 3.3% (P = 0.01), LDL-C by 4.5% (P = 0.004), and TG by 10.6% (P = 0.02), and increased HDL-C by 4.2% (P = 0.02). When subjects were divided on the basis of plasma and urine concentrations of the isoflavone metabolite, equol, equol producers and nonproducers did not differ in baseline lipids or in the effects of soy. Probiotics did not lower cholesterol or enhance the effects of soy. These results confirm a beneficial effect of soy on plasma cholesterol in mildly hypercholesterolemic postmenopausal women independent of equol production status, but do not support an independent or additive effect of these particular probiotic bacteria.

Cross-Over Studies↗

PubMed2004

Plasma phytoestrogens are not altered by probiotic consumption in postmenopausal women with and without a history of breast cancer.

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 concentrations did not differ between controls and survivors, although genistein tended to be lower in survivors at baseline (P = 0.15), and during soy (P = 0.16) and milk protein (P = 0.16) consumption. As expected, soy consumption increased plasma phytoestrogen concentrations (P < 0.0001). Plasma phytoestrogen concentrations and the number of equol producers did not differ between the S and S+P diets. At the same time, plasma equol concentrations as well as urinary equol excretion in 2 subjects were more than 7-fold different between the 2 diets. These results indicate that this particular probiotic supplement does not generally affect plasma isoflavones, although the large differences between plasma and urinary equol in some subjects suggest that equol producer status may be modifiable in some individuals.

Biological Availability↗

PubMed2003

Phyto-oestrogens.

Phyto-oestrogens are oestrogenic compounds found in plants and consist of isoflavones, lignans and coumestans. Epidemiological studies provide evidence for a protective role of isoflavones, and to a lesser extent lignans, against the development of numerous chronic diseases, including several cancers, cardiovascular disease and osteoporosis. The structural similarity of phyto-oestrogens to endogenous oestrogens has prompted the hypothesis that phyto-oestrogens exert hormonal or anti-hormonal effects relevant to the risk of hormone-dependent disease and/or their suitability as a dietary alternative to hormone replacement therapy. The many human studies that have evaluated the effects of isoflavones and lignans on various endpoints relating to risk of various diseases have greatly increased knowledge of how these compounds behave. At the same time, additional questions have been generated. For example, the increasing interest in extracting isoflavones from the soybean for incorporation into dietary supplements has raised important concerns regarding safety and efficacy. Overall, it is clear that phyto-oestrogens are an area of active and advancing research with great potential to continue to affect human health.

Animals↗

PubMed2003

Phytoestrogen supplement use by women.

Phytoestrogens are weak estrogens found concentrated in soybeans. Americans consume phytoestrogens primarily in traditional soy foods, soymilk and isolated soy protein added during food processing or consumed as a beverage. Extracted phytoestrogens are also marketed in numerous forms as dietary supplements regulated under the Dietary Supplement Health and Education Act. Consumers of phytoestrogen supplements tend to be peri- and postmenopausal women looking for an alternative to hormone therapy. Although there are no approved health claims for phytoestrogens at this time, numerous claims are being made regarding benefits to heart, bone, breast and general menopausal health. The data supporting these claims are generally not strong. The strongest data show that phytoestrogens reduce the number and intensity of hot flashes, although the reduction is a modest 10-20%. The studies showing cholesterol lowering have used soy protein rather than phytoestrogen extracts. The soy protein appears to be required for this effect, although phytoestrogen extracts may have other beneficial effects on the cardiovascular system. The data on bone metabolism are suggestive of possible benefits whereas the effects on the breast are the most poorly understood. Although most animal studies have shown cancer-preventive effects, a few recent studies suggest that soy phytoestrogens may stimulate breast cancer cell growth under certain circumstances. Before recommendations regarding phytoestrogen supplements can be safely made, we must have more information on the effects of the extracts on bone, heart and breast health. Until safety with respect to breast cancer is established, phytoestrogen supplements should not be recommended, particularly for women at high risk of breast cancer.

Animals↗

PubMed2002

Hormonal effects of soy in premenopausal women and men.

Over the past few years, there has been increasing interest in the possible hormonal effects of soy and soy isoflavone consumption in both women and men. Soy consumption has been suggested to exert potentially cancer-preventive effects in premenopausal women, such as increased menstrual cycle length and sex hormone-binding globulin levels and decreased estrogen levels. There has been some concern that consumption of phytoestrogens might exert adverse effects on men's fertility, such as lowered testosterone levels and semen quality. The studies in women have provided modest support for beneficial effects. One cross-sectional study showed serum estrogens to be inversely associated with soy intake. Seven soy intervention studies controlled for phase of menstrual cycle. These studies provided 32-200 mg/d of isoflavones and generally showed decreased midcycle plasma gonadotropins and trends toward increased menstrual cycle length and decreased blood concentrations of estradiol, progesterone and sex hormone-binding globulin. A few studies also showed decreased urinary estrogens and increased ratios of urinary 2-(OH) to 16alpha-(OH) and 2-(OH) to 4-(OH) estrogens. Soy and isoflavone consumption does not seem to affect the endometrium in premenopausal women, although there have been weak estrogenic effects reported in the breast. Thus, studies in women have mostly been consistent with beneficial effects, although the magnitude of the effects is quite small and of uncertain significance. Only three intervention studies reported hormonal effects of soy isoflavones in men. These recent studies in men consuming soyfoods or supplements containing 40--70 mg/d of soy isoflavones showed few effects on plasma hormones or semen quality. These data do not support concerns about effects on reproductive hormones and semen quality.

Animals↗

PubMed2002

Isoflavones and postmenopausal women: a critical review.

Isoflavonic phytoestrogens, or isoflavones, constitute a class of phytoestrogens that have properties similar to selective estrogen receptor modulators, and have attracted a substantial degree of attention in recent years, particularly as a possible alternative to the conventional hormone replacement therapy regimens used by postmenopausal women. Despite great promise, it is difficult to make many specific recommendations about their use at the current time, in light of the many outstanding questions that hopefully will be answered in the future by focused interventional studies involving humans. Studies to date indicate that the use of isoflavones to address vasomotor symptoms provides at most small benefits beyond a placebo effect, and no benefit for genital atrophy. As for postmenopausal women whose primary concern is cardiovascular disease, the recommendation of the American Heart Association to include soy protein foods as part of an otherwise healthy diet is well justified, and similarly the substitution of supplements containing soy protein for animal protein can also be recommended. The use of purified isoflavone supplements not containing soy protein may have some cardiovascular benefits, but these appear to be less substantial in degree than those provided by soy protein with isoflavones. In particular, more research is needed to assess the effects of isoflavones on osteoporosis, for which no recommendation regarding isoflavones can be made based on the current data. Also, isoflavones should not be taken by postmenopausal women for the specific purpose of decreasing their risk of breast or endometrial cancer, although, at least for those without pre-existing disease or at high risk, it seems quite unlikely that isoflavone use is harmful in this regard.

Cardiovascular Diseases↗

PubMed2002

Obesity, endogenous hormones, and endometrial cancer risk: a synthetic review.

Endometrial cancer is a disease of the affluent, developed world, where epidemiological studies have shown that > or =40% of its incidence can be attributed to excess body weight. An additional proportion may be because of lack of physical activity. Alterations in endogenous hormone metabolism may provide the main links between endometrial cancer risk, and excess body weight and physical inactivity. Epidemiological studies have shown increased endometrial cancer risks among pre- and postmenopausal women who have elevated plasma androstenedione and testosterone, and among postmenopausal women who have increased levels of estrone and estradiol. Furthermore, there is evidence that chronic hyperinsulinemia is a risk factor. These relationships can all be interpreted in the light of the "unopposed estrogen" hypothesis, which proposes that endometrial cancer may develop as a result of the mitogenic effects of estrogens, when these are insufficiently counterbalanced by progesterone. In our overall synthesis, we conclude that development of ovarian hyperandrogenism may be a central mechanism relating nutritional lifestyle factors to endometrial cancer risk. In premenopausal women, ovarian hyperandrogenism likely increases risk by inducing chronic anovulation and progesterone deficiency. After the menopause, when progesterone synthesis has ceased altogether, excess weight may continue increasing risk through elevated plasma levels of androgen precursors, increasing estrogen levels through the aromatization of the androgens in adipose tissue. The ovarian androgen excess may be because of an interaction between obesity-related, chronic hyperinsulinemia with genetic factors predisposing to the development of ovarian hyperandrogenism.

Age Distribution↗