Studies Soya

[MeDieViL]

Dietary supplements of soya flour lower serum testosterone concentrations and improve markers of oxidative stress in men.

Gardner-Thorpe D, O'Hagen C, Young I, Lewis SJ.

Department of Medicine, University Hospital of Wales, Cardiff, Wales, UK.

OBJECTIVE: We examined the effects on serum sex steroids, lipids and markers of oxidative stress of supplementing the diets of healthy male volunteers with scones made with soya flour. DESIGN: A randomized placebo controlled cross-over trial. SETTING: University Hospital of Wales. SUBJECTS: Twenty volunteers recruited by advertisement. INTERVENTIONS: Male volunteers ate three scones a day in addition to their normal diet for a period of 6 weeks. The scones were made with either wheat or soya flour (containing 120 mg/day of isoflavones). Blood was analysed for sex steroids (testosterone, dihydro-testosterone, oestradiol, oestrone, sex hormone binding globulin, albumin and the concentration of non-protein bound sex steroids were calculated), lipid profile (total cholesterol, high density lipoprotein cholesterol and triglycerides) and measures of oxidative stress (hydroperoxides, susceptibility of LDL to oxidation with copper and myeloperoxidase). RESULTS: The volunteers' mean age was 35.6 (s.d. 11.2) y. Total serum testosterone fell in volunteers taking the soya scones (19.3-18.2 nmol/l; 95% CI 1.01, 1.12; P=0.03). No significant changes were seen in the concentrations of the other serum sex steroids, albumin or sex hormone binding globulin throughout the study. Significant improvements in two of the three markers of oxidative stress were seen in volunteers taking soya scones. Lag time for myeloperoxidase rose from 55.0 to 68.0 min (95% CI -16.0, -3.5; P=0.009) and the presence of hydroperoxides decreased from 2.69 to 2.34 micro mol/l (95% CI 0.12, 0.71; P=0.009). There were no changes seen in serum triglycerides or cholesterol. CONCLUSIONS: We have shown that soya supplements reduce serum testosterone and improve markers of oxidative stress. These findings provide a putative mechanism by which soya supplements could protect against prostatic disease and atherosclerosis. Further dietary studies with clinical end points are warranted.

Soya phytoestrogens change cortical and hippocampal expression of BDNF mRNA in male rats.

File SE, Hartley DE, Alom N, Rattray M.

Psychopharmacology Research Unit and Biochemical Neuropharmacology Group, Centre for Neuroscience Research, King's College London, Hodgkin Building, Guy's Campus, SE1 1UL, London, UK.

Adult male hooded Lister rats were either fed a diet containing 150 microg/g soya phytoestrogens or a soya-free diet for 18 days. This concentration of phytoestrogens should have been sufficient to occupy the oestrogen-beta, but not the oestrogen-alpha, receptors. Using in situ hybridisation, significant reductions were found in brain-derived neurotrophic factor (BDNF) mRNA expression in the CA3 and CA4 region of the hippocampus and in the cerebral cortex in the rats fed the diet containing phytoestrogens, compared with those on the soya-free diet. No changes in glutamic acid decarboxylase-67 or glial fibrillary acidic protein mRNA were found. This suggests a role for oestrogen-beta receptors in regulating BDNF mRNA expression.

Brain aging and midlife tofu consumption.

White LR, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W.

National Institute on Aging, NIH, USA.

OBJECTIVE: To examine associations of midlife tofu consumption with brain function and structural changes in late life. METHODS: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews. RESULTS: Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0. CONCLUSIONS: In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.

Increased aggressive behavior and decreased affiliative behavior in adult male monkeys after long-term consumption of diets rich in soy protein and isoflavones.

Horm Behav. 2004 Apr;45(4):278-84.

Simon NG, Kaplan JR, Hu S, Register TC, Adams MR.

Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA.

Estrogen produced by aromatization of gonadal androgen has an important facilitative role in male-typical aggressive behavior that is mediated through its interaction with estrogen receptors (ER) in the brain. Isoflavones found in soybeans and soy-based dietary supplements bind ER and have dose- and tissue-dependent effects on estrogen-mediated responses. Yet, effects of isoflavone-rich diets on social and aggressive behavior have not been studied. We studied the effects of long-term (15 months) consumption of diets rich in soy isoflavones on spontaneous social behavior among adult male cynomolgus macaques (Macaca fascicularis) (n = 44) living in nine stable social groups. There were three experimental conditions which differed only by the source of dietary protein: casein and lactalbumin (no isoflavones), soy protein isolate containing 0.94 mg isoflavones/g protein, and soy protein isolate containing 1.88 mg isoflavones/g protein. In the monkeys fed the higher amount of isoflavones, frequencies of intense aggressive (67% higher) and submissive (203% higher) behavior were elevated relative to monkeys fed the control diet (P's < 0.05). In addition, the proportion of time spent by these monkeys in physical contact with other monkeys was reduced by 68%, time spent in proximity to other monkeys was reduced 50%, and time spent alone was increased 30% (P's < 0.02). There were no effects of treatment on serum testosterone or estradiol concentrations or the response of plasma testosterone to exogenous gonadotropin-releasing hormone (GnRH). The results indicate that long-term consumption of a diet rich in soy isoflavones can have marked influences on patterns of aggressive and social behavior.

Dietary soy and increased risk of bladder cancer: A prospective cohort study of men in Shanghai, China.

Int J Cancer. 2004 Nov 1;112(2):319-23.

Sun CL, Yuan JM, Wang XL, Gao YT, Ross RK, Yu MC.

USC/Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.

To verify our previous finding of a positive association between dietary soy and bladder cancer risk, we examined the association in a second, geographically distinct prospective cohort of Chinese subjects, the Shanghai Cohort Study. Briefly, 18,244 men aged 45-64 years were recruited between January 1986 and September 1989. As of December 31, 2002, 61 incident bladder cancer cases were identified. Information on soy consumption was obtained through in-person interviews at baseline using a food frequency questionnaire. Cox proportional hazard regression methods were used to estimate relative risks (RR) and their corresponding 95% confidence intervals (CI), with adjustment for age (years) at baseline interview, level of education and other potential confounders. Compared to men consuming soy less than once a week, the RR (95% CI) for those who consumed soy 1-<3 times per week, 3-<7 times a week and daily were 2.05 (0.80-5.29), 2.45 (0.89-6.76) and 4.61 (1.57-13.51), respectively (p for trend = 0.004), after adjustment for age, cigarette smoking and level of education. The soy-bladder cancer risk associations in smokers and non-smokers were comparable. The soy-bladder cancer relationship became stronger when the analysis was restricted to subjects with 2 or more years of follow-up.

hmm, soya lijkt me toch ni zo goed

[BBD]

Origineel gepost door MeDieViL

hmm, soya lijkt me toch ni zo goed

En dat was een verrasing voor jou?

[MeDieViL]

ik ben op de hoogte van die anti-soya sites, een verassing is het eigenlijk niet, maar het echte bewijs ontbrak nog
zo zijn er ook die anti-aspartaam, anti-melk sites, waar al lang uit studies is gebleken dat ze geen grond hebben om op te staan, dus moet je niet direct alles geloven.

[MeDieViL]

nog een paar studies

ndometrial effects of long-term treatment with phytoestrogens: a randomized, double-blind, placebo-controlled study.

Fertil Steril. 2004 Jul;82(1):145-8.

Unfer V, Casini ML, Costabile L, Mignosa M, Gerli S, Di Renzo GC.

A.G.UN.CO., Obstetrics and Gynecology Centre, Rome, Italy.

OBJECTIVE: To determine the effects of 5 years of treatment with soy phytoestrogens on histological characteristics of endometrium in postmenopausal women. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Centre of Perinatal and Reproductive Medicine, Department of Gynecological, Obstetrical, and Pediatric Sciences, University of Perugia, Italy. PATIENT(S): Three hundred seventy-six postmenopausal healthy women, all with intact uterus. INTERVENTION(S): Women were distributed in two different groups using randomized criteria: group A (n = 179) patients received soy tablets (150 mg of isoflavones per day) for 5 years; group B (n = 197) patients received identical appearing placebo tablets for 5 years. MAIN OUTCOME MEASURE(S): Results of endometrial histology from biopsies obtained at baseline, 30 months, and 5 years after the beginning of the treatment. RESULT(S): Two hundred ninety-eight women completed the 5-year treatment. No cases of malignancy were detected during biopsy. Seventy percent of women undergoing treatment with soy phytoestrogens had an endometrium classified as atrophic or nonassessable versus 81% receiving placebo. The occurrence of endometrial hyperplasia was significantly higher in group A (3.37% vs. 0%). CONCLUSION(S): Long-term treatment (up to 5 years) with soy phytoestrogens was associated with an increased occurrence of endometrial hyperplasia. These findings call into question the long-term safety of phytoestrogens with regard to the endometrium.

Reproductive effects in male and female rats of neonatal exposure to genistein.

Reprod Toxicol 2001 Jul-Aug;15(4):399-411

Nagao T, Yoshimura S, Saito Y, Nakagomi M, Usumi K, Ono H.

Department of Reproductive and Developmental Biology, Hatano Research Institute, Food and Drug Safety Center, Hadano, Kanagawa, Japan. nagaot@kb3.so-net.ne.jp

Sprague-Dawley rats were administered genistein orally at doses of 12.5, 25, 50, or 100 mg/kg on postnatal days 1 through 5 to examine its effects on reproductive function after puberty. In addition, preputial separation and vaginal opening as endpoints of sexual maturation, estrous cycling, sperm count, serum testosteron concentration, and histopathologic changes of reproductive organs of male and female rats were examined. Body weights of male and female rats exposed to genistein at any dose level examined were lower than those of controls. Timing of preputial separation in males and timing of vaginal opening were not affected by genistein treatment. The number of females showing estrous cycle irregularities was increased by genistein treatment. The fertility of female rats exposed neonatally to genistein at 100 mg/kg was disrupted, while neonatal exposure to genistein did not affect male fertility. Neither sperm counts nor serum testosteron concentration were changed by neonatal exposure to genistein. Female rats exposed neonatally to genistein at 100 mg/kg showed histopathologic changes in the ovaries and uterus, while male rats showed no histopathologic alterations in the gonads. The results of this study indicate that early neonatal exposure to genistein caused dysfunction of postpubertal reproductive performance as well as abnormal development of gonads in female but not in male rats.

[quote]

Infant feeding with soy formula milk: effects on the testis and on blood testosteron levels in marmoset monkeys during the period of neonatal testicular activity.

Hum Reprod 2002 Jul;17(7):1692-703

Sharpe RM, Martin B, Morris K, Greig I, McKinnell C, McNeilly AS, Walker M.

MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, 37 Chalmers Street, Edinburgh EH3 9ET, UK.

BACKGROUND: This study has addressed concerns about possible effects of feeding human infants soy formula milk (SFM). METHODS: This is a feeding study in marmosets, using a mainly co-twin design. From 4-5 until 35-45 days of age, co-twin males were fed by hand with either standard (cow) formula milk (SMA = controls) or with SFM for approximately 8 h each day (2 h at weekends) and intake related to bodyweight. Blood samples were collected at 18-20 and at 35-45 days of age in 13 sets of co-twins plus two non-twin males per group and, at the later age, seven sets of co-twins were killed and the testes and pituitary gland fixed for cell counts. RESULTS: Weight gain and formula intake were similar in both feeding groups. SMA-fed males had mean testosteron levels of 2.8-3.1 ng/ml, typical of the 'neonatal testosteron rise', whereas SFM-fed males exhibited consistently lower mean levels (1.2-2.6 ng/ml); paired comparison in SMA-and SFM-fed co-twins at day 35-45 revealed 53-70% lower levels in 11 of 13 co-twins fed with SFM (P = 0.004). Further evidence for suppression of testosteron levels in SFM-fed males came from comparison of the frequency of low testosteron levels (<0.5 ng/ml). In historical controls aged 35-45 days, two out of 22 values were <0.5 ng/ml, a similar frequency as found in control SMA-fed males (one out of 15 values <0.5 ng/ml). In contrast, 12 out of 15 values for SFM-fed males were <0.5 ng/ml (P < 0.001). There was no consistent relationship between SFM intake/g and testosteron levels. Paradoxically, the mean number of Leydig cells per testis was increased by 74% (P < 0.001) in co-twins fed SFM, when compared with their SMA-fed brothers, whereas no significant changes were found in numbers of Sertoli and germ cells. Because of the lack of gonadotrophin assays, the number of immunopositive LHbeta and FSHbeta cells in the pituitary gland, and their ratio, were determined but no consistent difference was found between SMA- and SFM-fed twins. CONCLUSIONS: Based on the average isoflavone content of the SFM brand used, intake of isoflavones was estimated at 1.6-3.5 mg/kg/day in the SFM-fed marmosets which is 40-87% of that reported in 4 month human infants fed on a 100% SFM diet. It is therefore considered likely that similar, or larger, effects to those shown here in marmosets may occur in human male infants fed with SFM. Whether the changes described result in longer-term effects is under investigation.

Soy isoflavone supplements antagonize reproductive behavior and estrogen receptor alpha- and beta-dependent gene expression in the brain.

Endocrinology 2001 Jul;142(7):2946-52

Patisaul HB, Dindo M, Whitten PL, Young LJ.

Center for Behavioral Neuroscience, Emory University, Atlanta, Georgia 30329, USA. hbeaupr@emory.edu

Epidemiological evidence suggests that isoflavone phytoestrogens may reduce the risk of cancer, osteoporosis, and heart disease, effects at least partially mediated by estrogen receptors alpha and beta (ERalpha and ERbeta). Because isoflavone dietary supplements are becoming increasingly popular and are frequently advertised as natural alternatives to estrogen replacement therapy, we have examined the effects of one of these supplements on estrogen-dependent behavior and ERalpha- and ERbeta-dependent gene expression in the brain. In the adult female rat brain, 17beta-estradiol treatment decreased ERbeta messenger RNA signal in the paraventricular nucleus by 41%, but supplement treatment resulted in a 27% increase. The regulation of ERbeta in the paraventricular nucleus is probably via an ERbeta-dependent mechanism. Similarly, in the ventromedial nucleus of the hypothalamus, supplement treatment diminished the estrogen-dependent up-regulation of oxytocin receptor by 10.5%. The regulation of oxytocin receptor expression in the ventromedial nucleus of the hypothalamus is via an ERalpha-dependent mechanism. Supplement treatment also resulted in a significant decrease in receptive behavior in estrogen- and progesterone-primed females. The observed disruption of sexual receptivity by the isoflavone supplement is probably due to antiestrogenic effects observed in the brain. These results suggest that isoflavone phytoestrogens are antiestrogenic on both ERalpha- and ERbeta-dependent gene expression in the brain and estrogen-dependent behavior.

Combined effects of dietary phytoestrogen and synthetic endocrine-active compound on reproductive development in Sprague-Dawley rats: genistein and methoxychlor.

Toxicol Sci 2002 Mar;66(1):91-104

You L, Casanova M, Bartolucci EJ, Fryczynski MW, Dorman DC, Everitt JI, Gaido KW, Ross SM, Heck Hd H.

CIIT Centers for Health Research, 6 Davis Drive, Research Triangle Park, North Carolina 27709-2137, USA. you@ciit.org

Humans and wildlife are frequently exposed to mixtures of endocrine active-compounds (EAC). The objective of the present study was to investigate the potential of the phytoestrogen genistein to influence the reproductive developmental toxicity of the endocrine-active pesticide methoxychlor. Three levels of genistein (0, 300, or 800 ppm) and two levels of methoxychlor (0 or 800 ppm) were used in this study. Sprague-Dawley rats were exposed to the two compounds, either alone or in combinations, through dietary administration to dams during pregnancy and lactation and to the offspring directly after weaning. Both compounds, methoxychlor in particular, were associated with reduced body growth at 800 ppm, but pregnancy outcome was not affected by either treatment. An acceleration of vaginal opening (VO) in the exposed female offspring was the only observed effect of genistein at 300 ppm. Exposure to 800 ppm genistein or 800 ppm methoxychlor caused accelerated VO and also altered estrous cyclicity toward persistent estrus in the female offspring. The estrogenic responses to genistein and methoxychlor administered together were apparently accumulative of the effects associated with each compound alone. Methoxychlor, but not genistein, delayed preputial separation (PPS) in the male rats. When administered with methoxychlor, genistein at 800 ppm enhanced the effect of methoxychlor on delaying PPS. Genistein and methoxychlor treatment did not change gender-specific motor activity patterns in either sex. To explore possible mechanisms for interaction between the two compounds on development, we performed estrogen receptor (ER)- and androgen receptor (AR)-based in vitro transcriptional activation assays using genistein and the primary methoxychlor metabolite 2,2-bis-(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE). While the in vitro assays supported the estrogenic effects of genistein and methoxychlor and the antiandrogenic effects of methoxychlor, the reactivity of these compounds with ERs alpha and beta could not predict the greater in vivo estrogenic potency of methoxychlor over genistein; nor could the potentiation of the methoxychlor effect on PPS by genistein be predicted based on in vitro HPTE and genistein reactions with the AR. Data from this study indicate that phytoestrogens are capable of altering the toxicological behaviors of other EACs, and the interactions of these compounds may involve complexities that are difficult to predict based on their in vitro steroid receptor reactivities.

[Big'r]

Origineel gepost door MeDieViL

ik ben op de hoogte van die anti-soya sites, een verassing is het eigenlijk niet, maar het echte bewijs ontbrak nog
zo zijn er ook die anti-aspartaam, anti-melk sites, waar al lang uit studies is gebleken dat ze geen grond hebben om op te staan, dus moet je niet direct alles geloven.

Precies!

Weet niet waar je dit vandaan hebt, en ook niet wat de intentie hiervan is, maar laten we om te beginnen ingaan op het effect van soja op testosteron.
Rattenstudies betekenen niks in vergelijking met 1 redelijk opgezette mensstudie.
Blijft over 1 mensstudie waarin ze het woord "testosteron" niet goed wisten te spellen in het engels. En dat van "The University Hospital of Wales" :

Dietary supplements of soya flour lower serum testosteron concentrations and improve markers of oxidative stress in men.
Total serum testosteron fell in volunteers taking the soya scones (19.3-18.2 nmol/l; 95% CI 1.01, 1.12; P=0.03).

Een goed opgezette studie (randomized placebo controlled cross-over trial).
Serum testosteron daalt, maar genoeg onderzoekers zien een daling van 19.3 naar 18.2 nmol/l als niet significant. Zeker niet dramatisch. Ook wordt niet gekeken naar insuline, IGF-1, GH en cortisol. Wanneer gesuggereerd zou worden dat iemand door soja minder hard zou groeien geeft deze studie daar 0,0 bewijslast voor:

Bijkomend voordeeltje van soja:
Significant improvements in two of the three markers of oxidative stress were seen in volunteers taking soya scones

Andere randomized onderzoeken laten zonder uitzondering geen effect zien van soja op testosteron:

Soy isoflavones affect platelet thromboxane A2 receptor density but not plasma lipids in menopausal women.
Twenty-nine healthy postmenopausal women were invited to take part in a randomised study to receive either 100 mg/day isoflavone supplement (n=15) or identical placebo capsules (n=14).
RESULTS: Blood pressure, body mass index, subcutaneous fat, insulin, serum lipoprotein, sex hormones and SHBG did not differ among groups.

Serum prostate-specific antigen but not testosteron levels decrease in a randomized soy intervention among men.
We randomized 24 men to a high or a low soy diet for 3 months. After a 1-month washout period, the men crossed over to the other treatment.
Twenty-three men aged 58.7+/-7.2 years completed the study. The compliance with the study regimen was high according to self-reported soy food intake and urinary isoflavone excretion.
A 14% decline in serum PSA levels (P=0.10), but no change in testosteron (P=0.70), was observed during the high soy diet in contrast to the low soy diet.

Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men.
Thirty-five men consumed milk protein isolate (MPI), low-isoflavone soy protein isolate (SPI) (low-iso SPI; 1.64 +/- 0.19 mg isoflavones/d), and high-iso SPI (61.7 +/- 7.35 mg isoflavones/d) for 57 d each in a randomized crossover design.
Other significant effects included a decrease in testosteron by the low-iso SPI relative to the MPI (P = 0.023) and high-iso SPI (P = 0.020) at d 29

Hormonal response to diets high in soy or animal protein without and with isoflavones in moderately hypercholesterolemic subjects.
Forty-two subjects (> 50 yr) with low-density lipoprotein cholesterol levels of > or = 3.36 mmol/l were fed each of 4 diets in randomized order for 6 wk/phase. All food and drink were provided. Diets contained 25 g soy or common sources of animal protein/4.2 MJ containing trace or 50 mg isoflavones/4.2 MJ. At the end of each diet phase, concentrations of estrone sulfate, estrone, estradiol, testosteron, androstendione, dihydrotestosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate were measured.
In postmenopausal women there was no significant effect of isoflavones on any of the hormones measured. In older men, dehydroepiandrosterone sulfate concentrations were lower after consuming the isoflavone (P = 0.0106) and higher after soy, compared with the animal protein diets (P = 0.0118)

Effect of soymilk consumption on serum estrogen and androgen concentrations in Japanese men.
Thirty-five men were randomly assigned to either a soymilk-supplemented group or a control group. The men in the soy-supplemented group were asked to consume 400 ml of soymilk daily for 8 weeks.
There was a significant difference between the two groups in terms of changes in serum estrone concentrations, which tended to decrease in the soy-supplemented group and increase in the control group over time. None of the other hormones measured (estradiol, total and free-testosteron, or sex hormone-binding globulin) showed any statistical difference between the two groups in terms of patterns of change.

3 Niet randomized onderzoeken (minder wetenschappelijke bewijslast). De eerste 2 laten een stijging van testosteron/vrije androgenen laat zien door soja. De 3e laat geen verschil zien:

Endocrine and cognitive effects of short-time soybean consumption in women.

Urinary sex steroid excretion levels during a soy intervention among young girls: a pilot study.

Effect of soy supplementation on endogenous hormones in postmenopausal women.

Aaaah lekkerz. Een review. Scheelt mij weer een hoop bullshit:

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 testosteron 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.

Deze ook maar even meenemen. Ben toch bezig:

Dietary soy has both beneficial and potentially adverse cardiovascular effects: a placebo-controlled study in men and postmenopausal women.
To address the cardiovascular effects of dietary soy containing phytoestrogens, we measured blood pressure (BP), lipids, vascular function (systemic arterial compliance and pulse wave velocity), and endothelial function (flow-mediated vasodilation) in a randomized, double-blind trial. Two hundred thirteen healthy subjects (108 men and 105 postmenopausal women), 50-75 yr old, received either soy protein isolate (40 g soy protein, 118 mg isoflavones) or casein placebo for 3 months. There were 34 withdrawals (16%), with 179 subjects (96 men and 83 women) completing the protocol. After intervention in the soy group, compared with casein placebo, urinary phytoestrogens increased, accompanied by a significant fall in BP reflected by the BP model (P < 0.01) encompassing mean change (+/-SEM) in systolic (-7.5 +/- 1.2 vs. -3.6 +/- 1.1 mm Hg, P < 0.05), diastolic (-4.3 +/- 0.8 vs. -1.9 +/- 0.7 mm Hg, P < 0.05), and mean BP (-5.5 +/- 1 vs. -0.9 +/- 1 mm Hg, P < 0.008). In the lipid model, soy induced greater changes, compared with placebo (P < 0.001). On individual analysis, significant contributors included a reduction in the low- to high-density lipoprotein ratio (-0.33 +/- 0.1 vs. 0.04 +/- 0.1 mmol/L, P < 0.05) and triglycerides (-0.2 +/- 0.05 vs. -0.01 +/- 0.05 mol/L, P < 0.05) and an increase in Lp(a) lipoprotein (+/- 95% confidence interval) [42 (range, 17-67) vs. 4 (range, -22-31) mg/L, P < 0.05], whereas total, low-density lipoprotein, and high-density lipoprotein cholesterol improved in both groups; but no treatment effect was demonstrated. The arterial functional model demonstrated no difference between groups; although again, overall function improved in both groups. On individual analysis, peripheral PWV (reflecting peripheral vascular resistance) improved with soy (P < 0.01), whereas flow-mediated vasodilation (reflecting endothelial function) declined (in males only), compared with casein placebo (P < 0.02). No effect of treatment on the hypothalamic-pituitary-gonadal axis was noted in males or females. In normotensive men and postmenopausal women, soy improved BP and lipids but, overall, did not improve vascular function. Potential adverse effects were noted, with a decline in endothelial function (in males only) and an increase in Lp(a). Further research in hypertensive and hyperlipidemic populations is needed.

1 Onderzoekje over soja bij training. Er staat niet bij wat het placebo inhield, maar dit haalt het idee dat soja opzich slecht zou zijn voor spiermassa behoorlijk onderuit:

Hormonal and metabolic response in elite female gymnasts undergoing strenuous training and supplementation with SUPRO Brand Isolated Soy Protein.
BACKGROUND: This study evaluates the metabolic and hormonal response in elite female gymnasts undergoing strenuous training and supplementation with SUPRO Brand Isolated Soy Protein. METHODS. EXPERIMENTAL DESIGN: 14 top female gymnasts (Romanian Olympic Team), took part in a study to examine their hormonal metabolic profile and to investigate any possible changes resulting from a 4-month program of strenuous training and daily supplementation with soy protein at a level of 1 g/kg body weight. Gymnasts wtare randomly assigned to one of two groups seven to the Supplemented Group (A) and seven to the Non-Supplemented Group (B). Both groups took part in the same program, which consisted of strenuous training for 4-6 hours/day (except on Sunday, controlled food intake and supplements including vitamins and minerals. Group A received a supplement of Sports Beverage Protein Mix with SUPRO Isolated Soy Protein (ISP) twice daily. Group B received a placebo identical in appearance and flavour. Selected parameters were measured before and after the 4-month training program (lean body mass, fat mass, serum hemoglobin, protein, fats, urea and creatinine, liver enzymes, serum total calcium and magnesium, immunoglobulins, urinary mucoproteins, serum T3 and T4, estradiol, progesterone, prolactin, testosteron and urinary 17-ketosteroids). RESULTS: Results demonstrated that the Supplemented Group (A) had an increase in lean body mass and serum levels of prolactin (p < 0.01) and T4 and a decrease in serum alkaline phosphetases (p < 0.01). The Non-Supplemented Group (B) had a decreased level of serum T4 and an increased level of urinary mucoproteins (p < 0.05). CONCLUSIONS: Our preliminary conclusions might suggest lower metabolic-hormonal stress in elite female gymnasts undergoing strenuous training and who received daily supplementation with isolated soy protein.

Moet ik nog doorgaan? Oke, het zijn "maar" epidimiologische onderzoeken, maar toch:

Soy milk intake in relation to serum sex hormone levels in British men.
Soy beans contain high levels of the isoflavones genistein and daidzein and their glycosides and have been implicated in the prevention of prostate cancer, possibly via their effects on sex hormone metabolism. The aim of this study was to assess the relation between dietary soy intake and sex hormone levels in a cross-sectional analysis of 696 men with a wide range of soy intakes. Soy milk intake was measured using a validated semiquantitative food frequency questionnaire, and serum hormone concentrations were measured by immunoassay. Multiple regression was used to investigate the association between soy milk intake, an index of isoflavone intake, and hormone levels after adjustment for pertinent confounders. Soy milk intake was not associated with serum concentrations of testosteron, free testosteron, androstanediol glucuronide, sex hormone-binding globulin, or luteinizing hormone. These results suggest that soy milk intake, as a marker of isoflavone intake, is not associated with serum sex hormone concentrations among free-living Western men.

Inverse association of soy product intake with serum androgen and estrogen concentrations in Japanese men.
The cross-sectional relationships of soy product intake and serum testosteron, estrone, estradiol, sex hormone-binding globulin, and dihydrotestosterone were examined in 69 Japanese men. Soy product intake was estimated from a semiquantitative food frequency questionnaire. Serum estradiol concentration was significantly inversely correlated with soy product intake (r = -0.32, p = 0.009), and serum estrone concentration was nonsignificantly inversely correlated with soy product intake (r = -0.24, p = 0.05) after controlling for age, body mass index, smoking status, and ethanol intake. Total and free testosteron concentrations were inversely correlated with soy product intake after controlling for the covariates, but these correlations were of border line significance (r = -0.25, p = 0.05 and r = -0.25, p = 0.06, respectively). Similar correlations were observed for these hormones with isoflavone intake from soy products. The data suggest that soy product intake may be associated with the endogenous hormone levels in Japanese men.

Mocht je toch in rattensstudies geloven, dan is deze wel interessant:

Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones.

[Big'r]

Onderwerp 2. Soja en het brein:

Brain aging and midlife tofu consumption.
OBJECTIVE: To examine associations of midlife tofu consumption with brain function and structural changes in late life. METHODS: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews. RESULTS: Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0. CONCLUSIONS: In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.

1 Enkele epidemiologische studie. Zoals je weet ligt de bewijslast van randomized controlled trials hoger, omdat op die manier niet de mensen zelf bepalen wat ze innemen, maar soja willekeurig wordt toegewezen, waardoor je andere factoren die het onderzoek kunnen beinvloeden meer uitsluit.

Psychological assessment of the effects of treatment with phytoestrogens on postmenopausal women: a randomized, double-blind, crossover, placebo-controlled study.
OBJECTIVE: To investigate the effects of soy isoflavones on mood and cognitive function in postmenopausal women. DESIGN: Randomized, double-blind, cross-over, placebo-controlled trial. SETTING: University Hospital, Milan, Italy; A.G.UN.CO. Obstetrics and Gynaecology Centre, Rome, Italy. PATIENT(S): Seventy-eight postmenopausal women. INTERVENTION(S): We administered 60 mg/day isoflavones or placebo for 6 months. After a washout period of 1 month, the patients who had been treated with phytoestrogens received placebo, and those who previously received placebo were administered phytoestrogens (for 6 months). MAIN OUTCOME MEASURE(S): Cognitive performance and mood were assessed by a battery of tests at the end of each treatment period. At the end of the study, the patients were also asked whether they preferred the first or second treatment. RESULT(S): The 17 scores on cognitive performance test and the 6 for mood assessments 6 showed an advantage for the treatment with phytoestrogens. Similarly, of the 8 visual analogue scales used to indicate mood, 7 improved significantly after the treatment with phytoestrogens. Moreover, 49 patients preferred phytoestrogens, 9 placebo, and 18 had no preference. The preference was not related to the order of treatment. CONCLUSION(S): These results suggest that isoflavones may have positive effects on postmenopausal women improving cognitive performance and mood.

Cognitive improvement after 6 weeks of soy supplements in postmenopausal women is limited to frontal lobe function.
OBJECTIVE: To assess the effects of 6 weeks of treatment with soy supplements on mood, menopausal symptoms, and cognition in postmenopausal women not taking other forms of hormone therapy. DESIGN: In a double-blind, placebo-matched parallel groups study, 50 postmenopausal women (aged 51-66 y) were randomly allocated to receive daily treatment with a soy supplement (Novasoy, 60 mg total isoflavone equivalents/day) or matching placebo capsules. They were tested at baseline before treatment began and after 6 weeks of treatment in tests of attention, memory, and frontal lobe function, and completed questionnaires to assess sleepiness, mood, and menopausal symptoms. RESULTS: After 6 weeks of treatment, there was a significant (P < 0.02) reduction in somatic menopausal symptoms in the group taking soy supplements, but there were no other significant effects of soy on menopausal symptoms or mood. On the test of nonverbal short-term memory, the soy group showed greater improvement than the placebo group (P < 0.03), but there were no effects of soy on long-term memory, category generation, or sustained attention. However, the soy treatment produced significantly better performance on the two tests of frontal lobe function, those of mental flexibility (simple rule reversal, P < 0.05; complex rule reversal, P < 0.03) and of planning ability (P < 0.05). CONCLUSIONS: The results suggest that the main improvement after 6 weeks of soy supplementation was in frontal lobe function. Significant improvements in the same three measures of frontal lobe function were previously found after 12 weeks of soy supplements in postmenopausal women. The effects of soy on memory seem less robust.

Effect of soy protein containing isoflavones on cognitive function, bone mineral density, and plasma lipids in postmenopausal women: a randomized controlled trial.
CONTEXT: Postmenopausal estrogen therapy has been posited to have some beneficial effects on aging processes, but its use has risks. Isoflavones, estrogenlike compounds naturally occurring in plant foods, might confer positive effects with fewer adverse effects. OBJECTIVE: To investigate whether soy protein with isoflavones improves cognitive function, bone mineral density, and plasma lipids in postmenopausal women. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, placebo-controlled trial of 202 healthy postmenopausal women aged 60 to 75 years, recruited from a population-based sample in the Netherlands, conducted between April 2000 and September 2001. INTERVENTION: Participants were randomly assigned to receive 25.6 g of soy protein containing 99 mg of isoflavones (52 mg genistein, 41 mg daidzein, and 6 mg glycetein or total milk protein as a powder on a daily basis for 12 months. MAIN OUTCOME MEASURES: Cognitive function was assessed using the following instruments: dementia, Mini-Mental State Examination; memory, Rey Auditory Verbal Learning Test, immediate recall, delayed recall, and recognition, the Digit Span forward and reversed, and the Doors test; complex attention tasks, Digit Symbol Substitution and Trailmaking, A1, A2, and B; and verbal skills, Verbal Fluency A and N, animals and occupations, and the Boston Naming Task. Bone mineral density of the hip and lumbar spine was assessed using dual-energy x-ray absorptiometry scanning. Lipid assessment included lipoprotein(a), total cholesterol, low-density lipoprotein, high-density lipoprotein, and triglycerides. RESULTS: A total of 175 women completed the baseline and at least 1 postintervention analysis and were included in the modified intent-to-treat analysis. Adherence was good (median plasma genistein levels, 17.2 and 615.1 nmol/L for placebo and soy group, respectively). Cognitive function, bone mineral density, or plasma lipids did not differ significantly between the groups after a year. CONCLUSION: This double-blind randomized trial does not support the hypothesis that the use of soy protein supplement containing isoflavones improves cognitive function, bone mineral density, or plasma lipids in healthy postmenopausal women when started at the age of 60 years or later.

Isoflavones and cognitive function in older women: the SOy and Postmenopausal Health In Aging (SOPHIA) Study.
OBJECTIVE: This study examines the effects of a dietary supplement of isoflavones on cognitive function in postmenopausal women. DESIGN: Participants for this 6-month, double-blind, randomized, placebo-controlled clinical trial were women who were in good health, were postmenopausal at least 2 years, and were not using estrogen replacement therapy. Between July 24, 2000, and October 31, 2000, 56 women aged 55 to 74 years were randomized; 2 in the placebo group and 1 in the active treatment group did not complete the 6-month evaluation, and none withdrew because of adverse effects. Women randomized to active treatment (n = 27) took two pills per day, each containing 55 mg of soy-extracted isoflavones (110 mg total isoflavones per day; Healthy Woman: Soy Menopause Supplement, Personal Products Company, McNeil-PPC Inc., Skillman, NJ, USA). Women assigned to placebo (n = 26) took two identical-appearing pills per day containing inert ingredients. Cognitive function tests administered at baseline and follow-up included the following: Trails A and B, category fluency, and logical memory and recall (a paragraph recall test assessing immediate and delayed verbal memory). RESULTS: At baseline, all women were cognitively intact; there were no significant differences by treatment assignment in age, education, depressed mood, or cognitive function (all P values > 0.10). Compliance was 98% and 97%, respectively, in the placebo and treatment groups; all women took at least 85% of their pills. The women in the treatment group did consistently better, both as compared with their own baseline scores and as compared with the placebo group responses at 6 months. Comparisons of percentage change in cognitive function between baseline and follow-up showed greater improvement in category fluency for women on active treatment as compared with the case of those on placebo (P = 0.02) and showed (nonsignificantly) greater improvement on the two other tests of verbal memory and Trails B. CONCLUSION: These results suggest that isoflavone supplementation has a favorable effect on cognitive function, particularly verbal memory, in postmenopausal women.

Heb er 2 reviews over kunnen vinden:

Soy and red clover for mid-life and aging.
Introduction Menopause is associated with mid-life, a time when many women begin to experience the signs and symptoms of aging, such as increases in blood pressure, changes in lipid profiles, loss of bone mass density, and diminished memory and cognition. Given the result of the Women's Health Initiative, many women no longer consider hormone therapy the first option for promoting healthy aging. Instead, they are turning to botanical and dietary supplement (BDS) products in place of hormone therapy. This paper reviews the evidence available for use of isoflavones from soy and red clover for the treatment or prevention of these health issues.Methods The MEDLINE and EMBASE databases were searched for articles relating to soy or red clover supplement use for prevention and/or treatment of heart disease, hyperlipidemia, osteoporosis, mood disorders and cognitive abilities. Studies were included if they were randomized, controlled trials and included peri- or postmenopausal women.Results Isoflavone products appear to be the most useful for improving lipid profiles; however, the evidence suggests that isoflavone extracts from soy are less effective than products containing soy protein or red clover isoflavones. Soy protein appears to reduce levels of total cholesterol and low density lipoprotein cholesterol, while red clover reduces levels of triglycerides and increases high density lipoprotein cholesterol. The data were somewhat less convincing, although promising, for increasing bone mass density and improving cognitive abilities.Conclusions Research suggests that isoflavones found in soy foods and red clover appear to have a small but positive health effect on plasma lipid concentrations, bone mass density, and cognitive abilities. Given the lack of serious safety concerns in the short term, it would appear that including soy and red clover in the diet of postmenopausal women, not withstanding a soy allergy, might be beneficial.

Soy isoflavones and cognitive function.
There is growing interest in the physiological functions of soy isoflavones, especially in whether they affect cognitive function and have beneficial effects on neurodegenerative diseases. Here we review the recent evidence from clinical and experimental studies supporting a role for soy isoflavones in cognitive function. Soy isoflavones may mimic the actions and functions of estrogens on brain, and they have been shown to have positive effects on the cognitive function in females; however, studies on their effects on spatial memory have not provided consistent results in males. Although data from humans, cultures, and animal models are currently insufficient for elucidating the metabolism of soy isoflavone actions on cognitive function and the nervous system, we suggest two putative pathways; (1) an estrogen receptor-mediated pathway and (2) via the inhibition of tyrosine kinase, in particular by genistein, which is one of the soy isoflavones. Although soy isoflavones appear to have a positive effect on brain function, further research is needed to determine not only the efficacy but also the safety of soy isoflavones on the nervous system and cognitive function.

MAAR... Zouden de hersenen van mannen anders op soja reageren dan die van vrouwen?

Soy-induced brain atrophy?
Epidemiological research has demonstrated a positive correlation between tofu consumption and brain atrophy in men. Because correlation does not prove causation, correlation-based hypotheses should be tested against the availability of possible causal mechanisms. While it has been shown that the soy phytoestrogen genistein inhibits neuroprotective functions in cell cultures, recent in-vivo findings strengthen the case for a possible causal mechanism of soy-induced neurodegeneration. The author suggests possible responses to this data regarding soy consumption.

[kiki84]

Zijn soja-eiwitten nu goed of niet? Kan niet zo goed Engels

[EricR]

Origineel gepost door Big'r

Precies!

Weet niet waar je dit vandaan hebt, en ook niet wat de intentie hiervan is,

Waar een groot gedeelte vandaan komt is wel duidelijk :

http://www.soyonlineservice.co.nz/04...vefunction.htm

Een site die fel gekeerd is tegen soja-gebruik. Samen met crap-sites zoals Mercola en Weston A Price. De motieven zijn niet echt duidelijk, maar op die sites wordt over het algemeen de waarheid nog wel eens geweld aangedaan.

Voordat er weer een opmerking wordt gemaakt over een soja-lobby, als die al bestaat dan is het voor dierlijk gebruik. Tussen de 95% en 99% van alle ter wereld geproduceerde soja wordt gebruikt als veevoeder.

[MeDieViL]

Origineel gepost door kiki84

Zijn soja-eiwitten nu goed of niet? Kan niet zo goed Engels

goed blijkbaar

crap-sites zoals Mercola en Weston A Price. De motieven zijn niet echt duidelijk

van mercola wel, hij verkoopt een of ander soja supplement met alle "gifstoffen" uit
vroeger vond hij levertraan supperbron van vitamine D, nu raad hij het af door de vitamine A omdat hij een of andere speciale lamp verkoopt

[EricR]

Ah de aap komt bij Mercola dus vanzelf uit de mouw.

Overigens ben ik geen voorstander van overmatig soja-gebruik, maar dat geldt eigenlijk voor ieder voedingsmiddel. Probleem is dat veel voedingsmiddelen soaj bevatten, wat je zonder lezen van het etiket eigenlijk niet direct zal weten.

[the better dayz]

Dus iedereen aan de soja??

[Loe]

dat jullie zin hebben om al die wetenschappelijke onderzoeken helemaal door te lezen