The effects of soy milk and isoflavone supplements on cognitive performance in healthy, postmenopausal women.
BACKGROUND
The decline in estrogen concentrations in women after menopause can contribute to health related changes including impairments in cognition, especially memory. Because of the health concerns related to hormone replacement therapy (HRT), alternative approaches to treat menopausal symptoms, such as nutritional supplements and/or diet containing isoflavones, are of interest.


OBJECTIVE
This study investigated whether soy isoflavones (soy milk and supplement) could improve cognitive functioning in healthy, postmenopausal women. PARTICIPANTS, INTERVENTION AND DESIGN: A total of 79 postmenopausal women, 48-65 years of age, completed a double-blind, placebo-controlled trial in which they were randomly assigned to one of three experimental groups: cow's milk and a placebo supplement (control); soy milk and placebo supplement (soy milk, 72 mg isoflavones/day); or cow's milk and isoflavone supplement (isoflavone supplement, 70 mg isoflavones/day).


METHODS
Cognitive functioning was assessed using various cognitive tasks before the intervention (baseline) and after the intervention (test).


RESULTS
In contrast to predictions, soy isoflavones did not improve selective attention (Stroop task), visual long-term memory (pattern recognition), short-term visuospatial memory (Benton Visual Retention Test), or visuo-spatial working memory (color match task). Also, the soy milk group showed a decline in verbal working memory (Digit Ordering Task) compared to the soy supplement and control groups.


CONCLUSIONS
Soy isoflavones consumed as a food or supplement over a 16-week period did not improve or appreciably affect cognitive functioning in healthy, postmenopausal women.
Fournier
L R
LR
Department of Psychology, Washington State University, Pullman, WA 99164-4820, USA. Fournier@wsunix.wsu.edu
Ryan Borchers
T A
TA
Robison
L M
LM
Wiediger
M
M
Park
J S
JS
Chew
B P
BP
McGuire
M K
MK
Sclar
D A
DA
Skaer
T L
TL
Beerman
K A
KA
D000368:Aged; D000375:Aging / Q000523:psychology*; D003071:Cognition / Q000187:drug effects* / Q000502:physiology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000494:pharmacology; D008568:Memory / Q000187:drug effects / Q000502:physiology; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D017698:Postmenopause; D011569:Psychiatric Status Rating Scales; D041942:Soy Milk
D007529:Isoflavones