Fabien S. Dalais

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.

The effects of soy protein containing isoflavones on lipids and indices of bone resorption in postmenopausal women.

objective To assess the effect of a dietary soy protein supplement containing isoflavones on lipids and indices of bone resorption in postmenopausal women.

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, 1.1] 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. (Menopause 2000;7;289‐296.

Randomised, Controlled, Cross-Over Trial of Soy Protein with Isoflavones on Blood Pressure and Arterial Function in Hypertensive Subjects

Objective: To examine the effects of dietary soy/isoflavones on 24 hr blood pressure profiles and arterial function [systemic arterial compliance (SAC), pulse wave velocity (PWV) and brachial arterial flow mediated vasodilation (FMD)] compared to non legume-based plant protein without isoflavones, in hypertensive subjects. Design: In a 6 month double-blind, placebo controlled, cross-over trial, 41 hypertensive subjects (26 men, 15 postmenopausal women), 30–75 years, received soy cereal (40 g soy protein, 118 mg isoflavones) and gluten placebo cereal, each for 3 months. Results: Thirty-eight subjects completed protocol with results expressed as mean or mean change (±SEM) with each intervention. Soy increased urinary isoflavones (daidzein: 8-fold; genistein: 8-fold; equol: 9-fold; ODMA: 18-fold) with no change during gluten placebo. There was no difference in the change in individual 24 hr ambulatory BP parameters (SBP: 2 ± 2 vs −1 ± 1 mmHg, p = 0.21; DBP: 1 ± 1 vs −1 ± 1 mmHg, p = 0.06) central BP (cSBP: −4 ± 2 vs 0 ± 2 mmHg, p = 0.2) or the change in arterial function (FMD: 0.3 ± 0.5 vs −0.2 ± 0.5%, p = NS; SAC: 0.02 ± 0.02 vs −0.02 ± 0.02 U/mmHg, p = NS; PWV central: −0.2 ± 0.2 vs 0.0 ± 0.2 m/sec, p = NS; PWV peripheral: 0.01 ± 0.3 vs −0.4 ± 0.4 m/sec, p = NS) noted between interventions. Analysis of the area under curve of 24 hr BP outputs demonstrated that soy protein compared to gluten protein resulted in higher 24 hr systolic BP by 2.3 mmHg (p = 0.003), a higher daytime systolic BP by 3.4 mmHg (p = 0.0002) and a higher daytime diastolic BP by 1.4 mmHg (p = 0.008). Overall 24 hr diastolic BP, night systolic BP and night diastolic BP were not significantly different between groups. Furthermore, soy protein compared to gluten protein resulted in higher 24 hr heart rates by 3.5 bpm (p < 0.0001). Conclusions: In hypertensive subjects, compared to gluten placebo, soy dietary supplementation containing isoflavones had no effect on arterial function, on average 24 hr ambulatory blood pressure parameters or central blood pressure in men and women with hypertension. Area under the curve of 24 hr profiles demonstrated that daytime BP was higher after soy compared to gluten.

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.

URINARY EXCRETION OF ISOFLAVONOID PHYTOESTROGENS IN CHINESE AND ANGLO-CELTIC POPULATIONS IN AUSTRALIA

The purpose of this cross-sectional study was to compare the urinary excretion of phytoestrogens in Australians of Chinese and Anglo-Celtic origins. Urine samples from individuals already participating in two cross-cultural studies on food habits and health status, were used in order to measure excretion of the two isoflavonoid phytoestrogens genistein and daidzein. The mean (± SEM) 24 h excretion of genistein and daidzein, was 614 ± 202 nmol and 688 ± 218 nmol in the Chinese population and 107 ± 31 nmol and 164 ± 63 nmol in the Anglo-Celtic population (p<0.001) respectively. Differences were also observed in food consumption where cereal and legume consumptions were significantly higher in the Chinese population (p<0.0001). The urinary excretion of phytoestrogen in the Melbourne Chinese and Anglo-Celtic is consistent with excretion rates of other populations.

The Tradition and Science of Estrogenic Plants

ABSTRACT Current research efforts in nutrition science are narrowing the knowledge gap between traditional use and scientific use of plants in treating various health conditions. This article outlines the ways in which phytoestrogens-natural estrogens derived from plants-effect human health. The different types and sources of phytoestrogens are reviewed, and the effects of phytoestrogens on cancer and other chronic diseases are examined. The difference in diets and incidence of chronic disease between Asian and American populations is examined in relation to the phytoestrogen consumption of each population.