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

Abstract

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.

Scientific Opinion on the substantiation of health claims related to soy isoflavones and protection of DNA, proteins and lipids from oxidative damage (ID 1286, 4245), maintenance of normal blood LDL cholesterol concentrations (ID 1135, 1704a, 3093a), reduction of vasomotor symptoms associated with menopause (ID 1654, 1704b, 2140, 3093b, 3154, 3590), maintenance of normal skin tonicity (ID 1704a), contribution to normal hair growth (ID 1704a, 4254), “cardiovascular health” (ID 3587), treatment of prostate c

“…The Panel notes that from the 12 human intervention studies provided from which conclusions can be drawn for the scientific substantiation of the claim, most of which have some methodological limitations and/or inadequate reporting, five studies (n=498 subjects analysed; range: 25-115 per group) with a duration of 12 weeks to 12 months using doses from 27 mg genistein to 100 mg of total isoflavones showed a statistically significant effect of soy isoflavones on vasomotor symptoms after one month , three months (Cheng et al, 2007;Crisafulli et al, 2004), four months (Han et al, 2002) and 10 months , whereas six studies (n=463 subjects analysed, range: 12-99 per group/period) with a duration of six weeks to six months using doses from 40 mg to 118 mg of total isoflavones did not show a statistically significant effect of soy isoflavones on vasomotor symptoms (Albertazzi et al, 2005;Faure et al, 2002;Khaodhiar et al, 2008;Knight et al, 2001;Kotsopoulos et al, 2000;St Germain et al, 2001), and that one study in 122 analysed subjects using a dose of 50 mg isoflavones for four months led to inconsistent results with regard to the effect soy isoflavones on vasomotor symptoms.…”

“…From the remaining human intervention studies provided, either separately in the consolidated list or in the systematic reviews, seven investigated the effect of soy isoflavones on both frequency and severity of hot flushes (Albertazzi et al, 2005;D'Anna et al, 2007;Khaodhiar et al, 2008;Knight et al, 2001;Nahas et al, 2007;St Germain et al, 2001;Upmalis et al, 2000), two investigated frequency only (Crisafulli et al, 2004;Faure et al, 2002) and three severity only (Cheng et al, 2007;Han et al, 2002;Kotsopoulos et al, 2000). Three of these studies also investigated the effect of soy isoflavones on night sweats (Cheng et al, 2007;St Germain et al, 2001;Upmalis et al, 2000).…”

“…In the double-blind, randomised, placebo-controlled trial by Kotsopoulos et al (2000), 94 post-menopausal women (mean age 59.5 years) of whom 80 % were experiencing menopausal symptoms (not different between groups, mean symptom score approx. 0.8 on a 3-point scale) were randomised to consume either 118 mg isoflavones in soy powder (n=44) or casein powder (n=50) twice daily in sachet form taken in the form of beverages for 12 weeks.…”

“…In the 10 studies which investigated the effect of soy isoflavones on severity of hot flushes, severity of hot flushes was assessed by self-rating scales in five studies (Cheng et al, 2007;D'Anna et al, 2007;Khaodhiar et al, 2008;Nahas et al, 2007;Upmalis et al, 2000), by the vasomotor sub-scale of the Greene Climacteric Scale in two studies (Albertazzi et al, 2005;Knight et al, 2001), by the vasomotor symptom score of the Kupperman Index in one study (Han et al, 2002), by an interviewer-administered menopausal index in one study (St Germain et al, 2001), and by a validated questionnaire in the remaining study (Kotsopoulos et al, 2000). In the three of the aforementioned studies which investigated night sweats, one study (Cheng et al, 2007) assessed the severity of night sweats only, one study (Upmalis et al, 2000) assessed the frequency of night sweats only, while St Germain et al (2001) assessed both of these measures of night sweats.…”

Pharmaceutical Prospects of Phytoestrogens

“…Clinical studies of the effects of phytoestrogens on the effect on postmenopausal syndrome are summarized in Table 1 [30, [60][61][62][63][64][65][66][67][68][69][70][71][72]. Most of the studies of isoflavones used soy products.…”