Effects of two different isoflavone supplement preparations on gene-expression in postmenopausal women

Alleged benefits experience by the consumption of soy in Asian countries have
been attributed to the isoflavone content of soy products. Amongst other
benefits, isoflavones are believed to relief menopausal symptoms and are
therefore often consumed in supplements form in Western countries. These
supplements contain relatively high amounts of isoflavones and are on the
market in different compositions. The question is whether supplements with
different compositions exert similar effects or if the effects differ
substantially.

Primary Objective:
• to study the effect of intake of two isoflavone preparations, as compared to
placebo, for eight weeks on gene-expression in Peripheral Blood Mononuclear
Cells (PBMCs) in post-menopausal women.

Secondary Objectives:
• to determine the association between isoflavone plasma levels and
gene-expression in PBMCs;
• to explore the difference between the two isoflavone preparations on
gene-expression;
• to explore the difference between the two isoflavone preparations on status
markers in plasma;
• to explore whether the severity of previous menopausal complaints is related
to the effect of isoflavones on PBMC gene-expression;
• To explore the influence of isoflavones on whole genome gene expression in
adipose tissue
• To compare isoflavone levels in plasma with the levels present in adipose
tissue
• To determine the association between isoflavone levels in adipose tissue to
gene expression in adipose tissue

Intervention study with two substudies; each substudy is a double blind placebo
controlled crossover intervention study. The first substudy has two groups:
*high daidzein* supplement versus placebo (n=18) and vice versa (n=18); the
second substudy also has two groups *high genistein* versus placebo (n=18) and
vice versa (n=18).

Two intervention periods of eight weeks with an one of the two isoflavone
supplements and a placebo for each subject and a washout period of 8 weeks in
between.

The subjects have to fill in a short screening questionnaire, a questionnaire
regarding their menopausal complaints. And twice a food frequency
questionnaire.
The subjects have to visit the research centre 6 times, 4 times to give a blood
samples and to be weighed. Twice of these 4 visits they can (voluntarily)
undergo a adipose tissue biopsy. The other two times the participants visit to
pick up new supplements and a diary. In total the subjects spend, actively,
around 5.5 hours in the study excluding travelling time.
There are only very limited risks for the particpants during the intervention.
The supplements that are used in the study are commercially available. The dose
that will be used is similar to doses recommended by the supplement
manufacturers on the packages, and has olso been used in other intervention
studies. Venapunctures and adipose tissue biopsies can occasionally cause a
local haematoma or bruise and some participants may report pain or discomfort.