Phytoestrogen Supplementation in Postmenopausal Women


The goal of the study was to assess the impact of soy and red clover derived phytoestrogens on serum lipids in postmenopausal women. Both soya and red clover have high phytoestrogen content. Phytoestrogens, a class of estrogenic molecules produced by plants bind to the estrogen receptor and are capable of producing estrogenic effects. Therefore, our hypothesis was that they can reduce the levels of serum lipids. Materials and Methods: Researchers investigated total cholesterol, cholesterol fractions and triglycerides in blood, before treatment and in six months periods, throughout 18 months. The study involved 74 healthy postmenopausal women, divided into three groups. The first group of 23 patients received red clover derived isoflavones, the second one with 26 patients got soy derived phytoestrogens, while the third, control group with 25 patients, was without medications.

Full Title of Study: “Impact of Phytoestrogens on Serum Lipids in Postmenopausal Women”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Single (Participant)
  • Study Primary Completion Date: June 2010

Detailed Description

A classic clinical sample was constructed. A total of 117 consecutive postmenopausal women who came to us in four months periods due to the postmenopausal symptoms (hot flushes, sleep disturbances, mood swings and vaginal dryness) were enlisted for the research. Out of them 74 fulfilled the inclusion criteria and were randomized. Randomization process was simple manual and was done in the way that every woman with the odd randomization number received soya while those with the even randomization number received red clover derived isoflavones. However, during the study neither the doctors nor the patients knew what the randomization was and what the medication was. Women in the control group did not receive any medications and were only used for comparison. Examinees for this group were randomly selected from healthy postmenopausal women who had regular colposcopic check-ups during the same period. Out of 186 such women, 111 fulfilled the inclusion criteria, and every third was recruited for the study. In such way patients have been randomly divided in three groups (soya – S, red clover – RC, control – C) consisting of 37 women each. However, 6 women had to be excluded from soya and 5 from red clover group, as they did not take treatment on regular basis. Moreover, 7 women from soya, 6 from red clover and 9 from control group were excluded as a result of developing health problems (hypertension in 11 cases and uterine bleeding in 8 cases and H-SIL in 3 cases). One woman from soya group wanted to start taking hormone replacement therapy. Three women decided to drop out from the control group. So, finally 23 women from soya group, 26 from red clover and 25 from control group had undergone the study to the end. Women were taking one capsule per day of either soya or red clover derived phytoestrogens, early in the morning, before meal. The soya daily dose contained 2 isoflavones: genistein (39mg) and daidzein (1mg), while the red clover capsule consisted of 4 isoflavones: biokain A (23mg), daidzein (1mg), formononetin (15mg) and genistein (1mg). Each patient was keeping self-reported daily diary of the therapy administration, symptoms and adverse reactions. Researchers investigated total cholesterol, cholesterol fractions (LDL, HDL) and triglycerides, in cubital vein blood of patients, as well as body height and weight for each subject (out of which Body Mass Index – BMI was calculated by the standard formula). Data were recorded at the study beginning and 6, 12 and 18 months after the treatment commencement. Standard tests for lipid level evaluation were carried out on Olympus AU 400 automatic analyzer with referral rates for triglycerides from 0,61 to 2,10 mmol/l, total cholesterol 3,63 – 6,46 mmol/l, HDL 0,75 – 1,99 mmol/l, LDL 1,60 – 4,78 mmol/l.


  • Drug: phytoestrogens
    • The red clover capsule consisted of 4 isoflavones: biokain A (23mg), daidzein (1mg), formononetin (15mg) and genistein (1mg).
  • Drug: phytoestrogens
    • The soya daily dose contained 2 isoflavones: genistein (39mg) and daidzein (1mg).

Arms, Groups and Cohorts

  • Experimental: soya phytoestrogens
  • Experimental: red clover phytoestrogens
  • No Intervention: No drugs

Clinical Trial Outcome Measures

Primary Measures

  • Change from baseline of serum lipids
    • Time Frame: 18 months
    • study begining, 6 months, 12 months, 18 months

Participating in This Clinical Trial

Inclusion Criteria

  • healthy postmenopausal women, not taking any medications (anti-osteoporotic, lipid-lowering, anti-hypertensive and hormone based) that could influence the study results, last menstrual cycle of the investigated women was at least 12 months before entering the study. Exclusion Criteria:

  • unfulfilled inclusion criteria at any time of the study, allergies or severe adverse reactions on the administered drugs, changing of the regular dietary habits, the study protocol interruption and the wish of the patient to withdraw from the study.

Gender Eligibility: Female

Minimum Age: 40 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • American Medical Academy, Serbia
  • Provider of Information About this Clinical Study
    • Principal Investigator: Tihomir Mihailovic, Dr – American Medical Academy, Serbia
  • Overall Official(s)
    • Tihomir Mihailovic, MD.PhD, Study Director, Ultramedica Clinic, American Medical Academy
    • Milan Terzic, Prof. dr, Principal Investigator, School of Medicine, University of Belgrade

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