A randomized controlled trial of phytoestrogen supplementation, growth and bone turnover in adolescent males.

OBJECTIVE: To assess the effect of phytoestrogens on bone turnover and growth in adolescent boys. DESIGN: Randomized double-blind placebo-controlled trial. SETTING: Single school in northwest Tasmania. PARTICIPANTS: Adolescent boys (treatment n=69, placebo n=59, mean age 16.8 y). INTERVENTIONS: Six weeks of isoflavone supplementation (Novasoy, 50 mg daily of isoflavone equivalents). Bone turnover markers (bone specific alkaline phosphatase (BAP) and pyridinoline creatinine ratio (PYR)) were measured at baseline and follow-up. RESULTS: Despite marked increases in urinary genistein and daidzein in the treatment arm (both P<0.001), there were no significant differences in BAP, PYR or short-term height or weight change. This applied to both intention-to-treat and per protocol analysis. Neither was there a significant correlation between urinary genistein and daidzein levels and BAP or PYR. CONCLUSIONS: Phytoestrogen supplementation to the level of usual Japanese dietary intake has no measurable effect on bone turnover in adolescent boys. Longer-term studies of bone density may be desirable but it is unlikely that there will be a large effect in either girls or boys given the lower endogenous oestrogen levels in boys.

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.

The effects of Chinese medicinal herbs on postmenopausal vasomotor symptoms of Australian women. A randomised controlled trial.

OBJECTIVE: To evaluate the effects of a defined formula of Chinese medicinal herbs (CMH) on menopausal symptoms. DESIGN: A double-blind randomised placebo-controlled trial. METHODS: Between August 1998 and April 1999, 55 postmenopausal Australian women recruited from an urban population completed 12 weeks of intervention with either a defined formula of CMH (n = 28) or placebo (n = 27) taken twice daily as a beverage. MAIN OUTCOME MEASURES: The primary end-point was change in frequency of vasomotor events (hot flushes and night sweats). The secondary end-points were changes in score for the domains measured in the Menopause Specific Quality of Life (MENQOL) Questionnaire. RESULTS: There was a reduction in average weekly frequency of vasomotor events with CMH (-15%; 95% CI, -31% to +1%) and with placebo (-31%; 95% CI, -42% to -21%). The difference between groups favoured the use of placebo; however, this was not significant (P=0.09). Although significant reductions in scores for the various domains of the MENQOL Questionnaire were observed for both CMH and placebo, there were no significant differences between the two treatment groups for any domain. There was evidence for effect modification by previous use of natural therapies for the vasomotor, physical and sexual domains of the MENQOL Questionnaire: women with no prior use of natural therapies for their menopausal symptoms responded to therapy, whereas prior users did not. CONCLUSIONS: The defined formula of CMH was no more effective than placebo in reducing vasomotor episodes in Australian postmenopausal women, or in improving any of the four symptom domains in the MENQOL Questionnaire. Three of the MENQOL Questionnaire domains were modified by prior use of natural therapies. This finding has implications for future studies.

Phytoestrogens and breast cancer in postmenopausal women: a case control study.

OBJECTIVE: To examine the association between isoflavones, androgens, and dietary composition and the risk of breast cancer in Australian postmenopausal women. DESIGN: Eighteen women with recently diagnosed breast cancer before surgery and 20 controls were recruited over a 12-month period. Both cases and controls were similarly assessed for urinary isoflavones, serum and urinary sex steroids, and dietary intake. RESULTS: Women with breast cancer had lower 24-h urinary daidzein compared with controls (cases: 31 [95% CI: 4, 234] nmol/day; controls: 427 [95% CI: 4, 234] nmol/day; p = 0.03), and there was a trend to lower urinary genistein excretion (cases: 25 [95% CI: 5, 132] nmol/day; controls: 155 [95% CI: 43, 550] nmol/day; p = 0.08). Total testosterone was higher in women with breast cancer compared with controls (cases: 1.3 [95% CI: 1.1, 1.5] nmol/L; controls: 1.0 [95% CI: 0.8, 1.11 nmol/L; p = 0.05). No significant differences were found for serum sex hormone binding globulin, free androgen index, dehydroepiandrosterone sulphate, estradiol and progesterone, or in urinary androgen metabolites, or in dietary intake with regard to fat, carbohydrate, protein, or fiber consumption between cases and controls. CONCLUSIONS: This preliminary study is the first report of low urinary daidzein and genistein in postmenopausal women with breast cancer. These findings are in keeping with the increasing observational data demonstrating a protective effect from phytoestrogens on breast cancer risk.

Effect of meat replacement by tofu on CHD risk factors including copper induced LDL oxidation.

OBJECTIVE: To investigate the effect of replacing lean meat with a soy product, tofu, on coronary heart disease risk factors including serum lipoproteins, lipoprotein (a), factor VII, fibrinogen and in vitro susceptibility of LDL to oxidation. DESIGN: A randomized cross over dietary intervention study. SETTING: Free-living individuals studied at Deakin University. SUBJECTS: Forty-five free-living healthy males aged 35 to 62 years completed the dietary intervention. Three subjects were non-compliant and excluded prior to analysis. INTERVENTIONS: A diet containing 150 grams of lean meat per day was compared to a diet containing 290 grams of tofu per day in an isocaloric and isoprotein substitution. Each dietary period was one month duration. RESULTS: Analysis of the seven-day diet record showed that diets were similar in energy, protein, carbohydrate, total fat, saturated and unsaturated fat, polyunsaturated to saturated fat ratio, alcohol and fiber. Total cholesterol and triglycerides were significantly lower, and in vitro LDL oxidation lag phase was significantly longer on the tofu diet compared to the meat diet. The hemostatic factors, factor VII and fibrinogen, and lipoprotein(a) were not significantly affected by the tofu diet. CONCLUSIONS: The increase in LDL oxidation lag phase would be expected to be associated with a decrease in coronary heart disease risk.

The effects of soy protein containing phytoestrogens on menopausal symptoms in postmenopausal women.

OBJECTIVE: To analyze the impact of soy protein dietary supplements containing phytoestrogens on menopausal symptoms in healthy postmenopausal women. METHODS: A double-blind, placebo-controlled trial was conducted in 94 healthy postmenopausal women aged 50-75 years, with 44 randomized to soy supplements containing 118 mg of isoflavones (daidzein, genistein, glycitein and their respective glycosides), and 50 to an identically presented casein placebo. A validated questionnaire on menopausal symptoms was administered at baseline and at 3 months of treatment. Compliance was assessed by high-performance liquid chromatography assay of urinary phytoestrogens. Statistical analysis was completed using non-parametric statistical methods and multivariate analysis. RESULTS: At baseline 80% of women recruited were experiencing menopausal symptoms, although symptom severity was mild. Those consuming phytoestrogen supplements had 13- and 17-fold increases in urinary excretion of genistein and daidzein, respectively, with no change in the placebo group. Active soy supplements did not significantly alter either individual symptoms or specific symptom category scores when compared to placebo. Within-group comparisons revealed that the active group reported a significant improvement in vaginal dryness (p = 0.01), libido (p = 0.009), facial hair (p = 0.04) and dry skin (p = 0.027). However, similarly, those on placebo reported an improvement in libido (p = 0.015), facial hair (p = 0.014) and dry skin (p = 0.011) but not vaginal dryness. CONCLUSIONS: In this group of 94 older postmenopausal women with a high frequency of mild menopausal symptoms, 3 months of soy supplements containing phytoestrogens did not provide symptomatic relief compared with placebo.

Risk science and communication issues and challenges for food: an Australian perspective.

From any perspective, whether it be Australia or other countries, the issue of risk and food is one that includes all sectors of the community. The expansion of information technology and globalisation is making society as a whole more knowledgeable and expectant of safer foods with minimal risk. There is risk in everything and the basis of risk science is one that involves a number of established steps such as risk assessment, management and communication. The evolution of food technology, production and dietary habits, together with changes in trade, will no doubt raise new safety issues and governments need to be abreast of risk science to assess such changes.

Tempe, a nutritious and healthy food from Indonesia.

Tempe is a fermented soy bean product originally made by Central Javanese people through fermentation with Rhizopus species. Although there is evidence of earlier fermentation of soy, tempe had appeared in the Central Javanese food pattern in the 1700s. Through its extensive use in main meals and snacks, it has led to people in the Jakarta prectinct having the highest known soy intake in the world and accordingly of the isoflavones contained. This provides an unique opportunity to consider the health effects of tempe (and soy), both beneficial and potentially toxic. Apparent health benefits are bowel health, protection against cardiovascular disease, certain cancers (e.g. breast and prostate) and menopausal health (including bone health). The long use of tempe at all stages of life, without recognised adverse effects, suggests it is relatively safe at the levels of intake seen in Central Java. However, further research on soy, both fermented and non-fermented, in Central Java should yield more insight into the mechanisms of action and the safe ranges of intake.

Phytoestrogens in health and disease.

Phytoestrogens are compounds found in a wide variety of plant foods that historically are said to exhibit estrogen-like activity and, more recently, have been reported to display both estrogenic and anti-estrogenic effects. Population-based studies have been interpreted to suggest that consumption of a phytoestrogen-rich diet is protective against breast, prostate, and bowel cancer and cardiovascular disease and ameliorates estrogen-deficiency symptoms in postmenopausal women. Consequently, there is a global movement towards increased consumption of phytoestrogen-rich foods and tabletized concentrated isoflavone extracts are being heavily promoted. Evaluating the effects and hence the potential benefits and risks of phytoestrogens is a complex task. The interindividual diversity and complexity in dietary phytoestrogen absorption and metabolism make the bioactivity of these compounds unpredictable. Epidemiological studies of relationships between phytoestrogens and cancer and cardiovascular disease that take into account confounding factors are scarce. Results of many of the in vitro and in vivo studies are conflicting and confusing. These compounds do not simply mimic the effects of human steroidal estrogen but rather demonstrate both similar and divergent actions. The ultimate actions of these compounds in specific cells are determined by many factors, including the relative levels of estrogen receptor (ER) alpha and ER beta and the diverse cocktail of co-activators and co-repressors present in any given cell type. Therefore, effects vary according to the phytoestrogen studied, cell line, tissue, species, and response being evaluated. Overall, it is naive to assume that exposure to these compounds is always good; inappropriate or excessive exposure may be detrimental. Extensive documentation of the specific intracellular effects of the various phytoestrogens in different tissues, the relationships between timing and duration of exposure and disease, and results from prospective randomized studies in humans of their clinical effects and potential side effects are essential. Only then can widespread recommendations regarding the dietary and pharmacological intake of these compounds be made.

Effects of dietary phytoestrogens in postmenopausal women.

The aim of this study was to test the hypothesis that increased dietary intake of phytoestrogens reduces the health impact of the menopause. To test this hypothesis, a double-blind, randomized, entry-exit, cross-over study was conducted to assess the effects of three dietary manipulations--soy and linseed diets (high in phytoestrogens) and a wheat diet (low in phytoestrogens). Postmenopausal women were recruited and randomly assigned to one of the three dietary regimens. Urinary phytoestrogen concentrations, hot flush rate, vaginal smears, bone mineral density and bone mineral content were assessed for two 12-week periods. Comparative analysis showed no significant differences, but, when analyzed separately, groups consuming high phytoestrogen diets had between 10 and 30 times higher urinary excretion of phytoestrogens compared to those consuming the low phytoestrogen diet (p < 0.01). Study participants consuming soy, linseed and wheat diets had a 22% (not significant, n.s.), 41% (p < 0.009) and 51% (p < 0.001) reduction in hot flush rate; a 103% (p < 0.04), 5.5% (n.s.) and 11% (n.s.) increase in vaginal cytology maturation index; and a 5.2% (p < 0.04), 5.2% (n.s.) and 3.8% (n.s.) increase in bone mineral content, respectively. No changes were detected in bone mineral density. The differential effects of high phytoestrogen dietary manipulations on outcomes may represent tissue-specific responses to isoflavones and lignans contained in soy and linseed, respectively. Whilst health outcome measures were not significantly different between groups, the data obtained from separate analysis suggest that phytoestrogens in soy and linseed may be of use in ameliorating some of the symptoms of menopause. Furthermore, the significant decrease in hot flush rate in the wheat group cannot be attributable to phytoestrogens measured in this study. Due to subject variability, larger studies are still needed to evaluate population benefit.

Women who spontaneously quit smoking in early pregnancy.

Spontaneous quitters are prepregnancy smokers who quit by the time of their first antenatal visit. We recruited 192 self-declared spontaneous quitters and 407 smokers at their first visit to the antenatal clinic at the Royal Women's Hospital during April, 1994-May, 1995. Spontaneous quitters made up 23% of prepregnancy smokers. Information about self-declared quitters and smokers was collected by self-completed questionnaires. Urine samples collected at the first visit and in late pregnancy were assayed for cotinine to validate smoking status. A cut-off urinary concentration of > or = 653 nmol/L cotinine was used to determine active smoking. At the first visit, 20% of the self-declared spontaneous quitters were smoking and by late pregnancy, regardless of their initial biochemically verified status, 27% were smoking. Spontaneous quitters were different from women who said they were still smoking at their first antenatal visit, in a range of demographic variables and measures of addictive behaviour.