The Effect of Isoflavone Supplement Intake on Gene-expression in Postmenopausal Women
The Effect of Isoflavone Supplement Intake on Gene-expression in Postmenopausal Women
Alleged benefits experienced 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 relieve menopausal symptoms and are therefore often consumed in supplement form in Western countries. These supplements contain relatively high amounts of isoflavones, and the question is if these concentrations still exert beneficial effects or whether negative effects become dominant. Therefore, the investigators will study the effect of intake of one dose of isoflavones, as compared to placebo, for eight weeks on gene-expression in Peripheral Blood Mononuclear Cells (PBMCs) in post-menopausal, equol-producing women.
Primary Objective: to determine the effect of intake of one dose of isoflavones, as compared to placebo, for eight weeks on gene-expression in Peripheral Blood Mononuclear Cells (PBMCs) in post-menopausal, equol-producing women.
Secondary Objectives: to determine the association between isoflavone plasma levels and gene-expression in PBMCs; to determine the variation of isoflavone plasma levels between subjects after intake of isoflavones for four and eight weeks; to explore whether PBMC gene-expression markers identified after 8 weeks isoflavone intervention are already present after 4 weeks intervention; to explore whether the severity of previous menopausal complaints is related to the effect of isoflavones on PBMC gene-expression; and to explore the association between isoflavone levels in plasma and spot urine.
Study design: Double-blind placebo controlled crossover intervention study
Study population: Thirty-six healthy females, 45-70 years, post-menopausal and equol-producing
Intervention: Two intervention periods of eight weeks with a isoflavone supplement or a placebo and a washout period of 8 weeks in between.
Main study parameters/endpoints: The main study parameter is gene-expression in PBMCs measured by micro-arrays.
Inclusion Criteria:
Exclusion Criteria: