Use Of Isoflavone Supplements Research Articles

Use of isoflavone supplements is associated with reduced postmenopausal breast cancer risk

Botanical supplements are widely used and contain diverse ingredients, including isoflavones. Food-based isoflavones have been associated with reduced breast cancer risk. However, no study has comprehensively evaluated supplements identified by isoflavone content and breast cancer risk. Associations between ever use of 28 isoflavone supplements and breast cancer risk in Ontario, Canada were evaluated using cases (n = 3,101) identified in 2002-2003 from the Ontario Cancer Registry and controls (n = 3,471) identified through random digit dialing methods. Multivariate logistic regression was used to estimate age-adjusted odds ratio (AOR) and 95% confidence intervals (CI). Several individual supplements were associated with reduced breast cancer risk (e.g., Natural HRT; AOR = 0.39; 95% CI: 0.22, 0.69; n(users) = 58). Use of any isoflavone supplements was associated with reduced risk when ≥ 3 were ever used (AOR = 0.68; 95% CI: 0.54, 0.86; n(users) = 332; p(trend) = 0.008) or any was taken >5 years (AOR = 0.75; 95% CI: 0.60, 0.94; n(users) = 325; p(trend) = 0.01); high content supplements were consistently associated with reduced risk. Risk reduction was confined to postmenopausal breast cancer for both individual and combined supplements, and was strongest in the latter among high content users who ever took ≥ 3 supplements (AOR = 0.55; 95% CI: 0.38, 0.81; n(users) = 118; p(trend) = 0.04) or any >5 years (AOR = 0.47; 95% CI: 0.27, 0.81; n(users) = 60; p(trend) = 0.03). Associations did not differ by estrogen-progesterone tumor receptor status. In conclusion, isoflavone supplements were associated with decreased postmenopausal breast cancer risk. Further research to examine these novel findings is warranted, given the low supplement use and potential limitations of our results.

Posicionamiento de la Asociación Española para el Estudio de la Menopausia sobre el uso clínico de las isoflavonas en el climaterio

IntroductionWestern countries have shown an increasing interest in the use of soya isoflavones to treat aging and menopause-related diseases and their associated symptoms, stimulating a proliferation of studies, many of which report contradictory results. Consequently, the role of isoflavones was assessed by the Spanish Menopause Society (SMS) using the most reliable scientific evidence. Material and methodsA panel of experts on isoflavones was gathered. The selected studies were obtained by electronic search engines, Medline (1966-March 2007) and the Cochrane Controlled Clinical Trials Registry. ResultsThe various reviews and meta-analysis on the effects of Isoflavones on women’s health are controversial. The contradictory results may be due, among other factors, to the lack of uniformity in the compounds under study. Data on doses and genisteine content have indicated beneficial effects on lipid profile, like antioxidants, as well as a mild decrease in hot flushes. Some studies suggest a positive effect on bone mass. However few data are available on other aspects such as breast, estrogendependent cancer, cognitive function, or skin ConclusionsIn certain situations, isoflavones can be a therapeutic alternative during the climacteric period. However, before general recommendations on the use of isoflavone supplements can be made, more specific clinical trials should be performed. These studies should be adequately designed, with supplements that are standarized according to isoflavone content and types, a sufficient number of patients and study duration

Effect of Isoflavones on Cardiovascular Health: Low But Not Out Either

Isoflavones, an important class of flavonoids that are found at extremely high levels in soy have gained considerable attention for their potential in improving risk factors for cardiovascular disease. The three major extensively studied soy isoflavones are genistein, daidzein and glycetein [1]. The US Food and Drug Administration (FDA) in 1999 and the American Heart Association in (AHA) in 2000 recommended that soy protein containing foods may be protective against cardiovascular disease (CVD) [2, 3]. But in 2006, the AHA analysis suggests that the use of isoflavone supplements in food or pills is not recommended [4]. However, strong scientific evidence has been emerging recently related to the nutritional benefits of flavonoids including isoflavones [5]. A recent study of flavonoid intake and the risk of ischemic stroke and CVD mortality suggest that high intake of flavonoids may be associated with decreased risk of ischemic stroke and possibly reduced CVD mortality [6]. In another study in U.S adults the intake of dietary flavonoids including daidzein and genistein was inversely associated with serum levels of C-reactive protein (CRP) a biomarker for chronic inflammation and a sensitive risk factor for CVD [7]. It is reported that genistein upregulates the gene expression of antioxidant enzyme manganese-superoxide dismutase (Mn SOD) and antioxidant metallothionein expression [8, 9]. Increased expression of catalase in human hepatoma cells by daidzein has also been recently reported [10]. In vitro and in vivo studies have demonstrated that soy isoflavones genistein and daidzein may be useful antigenotoxic antioxidants by scavenging free radicals, inhibiting lipid peroxidation and protecting against oxidative DNA damage [11]. Recent reports reveal that genistein exhibit vascular protective effects by targeting on important signaling molecules in vascular endothelial cells including upregulation of human endothelial nitric oxide synthase [12]. Why is the inconsistency in clinical study reports of flavonoids? Key questions that need to be addressed include the gut bacterial metabolism of daidzein and its metabolites especially equol since it has longer half-life and greater biological activity, including superior antioxidant activity [13]. Recently the vasorelaxant and antioxidant activity of equal have been reported in carotid and cerebral arteries [14]. Using microarray analysis it has been found that isoflavone treatment in subjects who have the capacity to produce equal differentially affects gene expression as compared to non-producers, supporting the significance of equal production [15]. Thus the link between daidzein metabolizing phenotypes and the interaction of its metabolites at the gene level need to be further probed. And finally nutrigenomic and nutrigenetic aspects of isoflavones on CVD have to be studied in detail before any final verdict on the cardioprotective effects of these bioactive nutrients.

Soy Protein, Isoflavones, and Cardiovascular Health

This editorial summarizes the recent American Heart Association (AHA) Science Advisory on soy protein and isoflavones (phytoestrogens) published in the February 21, 2006, issue of Circulation .1 Soy protein and isoflavones have gained considerable attention for their potential role in improving risk factors for cardiovascular disease. This scientific advisory report assesses the more recent work published on soy protein and its component isoflavones. In 22 randomized trials, isolated soy protein with isoflavones compared with milk or other proteins decreased LDL cholesterol concentrations in most studies; the average effect was approximately 3%. This reduction is very small compared with the large amount of soy protein tested in these studies, averaging 50 g, approximately half the usual total daily protein intake. No significant effects were evident on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure. Among 19 studies of soy isoflavones, the average effect on LDL cholesterol and other lipid risk factors was nil. Soy protein or isoflavones have not been shown to lessen vasomotor symptoms of menopause, and results are mixed regarding slowing of postmenopausal bone loss. The efficacy and safety of soy isoflavones for preventing or treating cancer of the breast, endometrium, and prostate are not established; evidence from clinical trials is meager and cautionary as regards a possible adverse effect. For this reason, use of isoflavone supplements in food or pills is not recommended. Thus, earlier research indicating that soy protein compared with other proteins has clinically important favorable effects has not enjoyed confirmation. In contrast, many soy products should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat. In October 1999, the US Food and Drug Administration (FDA) approved labeling for foods containing soy protein as protective against coronary heart disease.2 …

Soy Protein, Isoflavones, and Cardiovascular Health

Soy protein and isoflavones (phytoestrogens) have gained considerable attention for their potential role in improving risk factors for cardiovascular disease. This scientific advisory assesses the more recent work published on soy protein and its component isoflavones. In the majority of 22 randomized trials, isolated soy protein with isoflavones, as compared with milk or other proteins, decreased LDL cholesterol concentrations; the average effect was approximately 3%. This reduction is very small relative to the large amount of soy protein tested in these studies, averaging 50 g, about half the usual total daily protein intake. No significant effects on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure were evident. Among 19 studies of soy isoflavones, the average effect on LDL cholesterol and other lipid risk factors was nil. Soy protein and isoflavones have not been shown to lessen vasomotor symptoms of menopause, and results are mixed with regard to soy's ability to slow postmenopausal bone loss. The efficacy and safety of soy isoflavones for preventing or treating cancer of the breast, endometrium, and prostate are not established; evidence from clinical trials is meager and cautionary with regard to a possible adverse effect. For this reason, use of isoflavone supplements in food or pills is not recommended. Thus, earlier research indicating that soy protein has clinically important favorable effects as compared with other proteins has not been confirmed. In contrast, many soy products should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat.