Postmenopausal estrogen decline is implicated in several age-related physical and psychological changes in women, including decreases in perceived quality of life (QoL). A number of trials with hormone therapy showed beneficial effects of the intervention on parameters of quality of life. However, because of known or suspected serious side-effects of conventional hormone therapy there is a need for alternatives.
We conducted a double-blind randomized placebo-controlled trial with soy protein, containing 52 mg genistein, 41 mg daidzein, and 6 mg glycitein (aglycone weights), or milk protein (placebo) daily for 1 year. For this trial, we recruited 202 postmenopausal women aged 60 to 75 years.
At baseline and at final visit, participants filled in the Short Form of 36 questions (SF-36), the Questionnaire on Life Satisfaction Modules (QLSM), and the Geriatric Depression Scale (GDS). For the placebo group scores on all dimensions of the SF-36 and the QLSM decreased during the intervention year, except for the dimension "role limitations caused by physical problems." The soy group showed increases on two dimensions of the SF-36 ("social functioning" and "role limitations caused by physical problems") and on one dimension of the QLSM. There were however no statistically significant differences in changes of scores between the two intervention groups. For the GDS similarly, no significant differences were found between the groups.
In conclusion, the findings in this randomized trial do not support the presence of a marked effect of soy protein substitution on quality of life (health status, life satisfaction, and depression) in elderly postmenopausal women.
In a randomized, placebo-controlled trial among 202 older postmenopausal women, no effects were found of soy protein containing isoflavones on quality of life (health status, life satisfaction, and depression).
From the 1Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands; and 2Cancer Prevention Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA.
Received November 4, 2003; revised and accepted March 15, 2004.
The study was financially supported by The Netherlands Organization for Scientific Research (NWO) nr. 014-91-024, The Netherlands Organization for Health Research and Development (ZON) nr. 2200.0048.
Address for correspondence: Y.T. van der Schouw, PhD, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, D01-335, 3508 GA Utrecht, The Netherlands. E-mail: firstname.lastname@example.org.