Effects of the phytoestrogen genistein on hot flushes, endometrium, and vaginal epithelium in postmenopausal women: a 2-year randomized, double-blind, placebo-controlled study.
OBJECTIVE
To evaluate in a 24-month, prospective, randomized, double-blind, placebo-controlled study whether pure administration of the phytoestrogen genistein (54 mg/d) might reduce the number and severity of hot flushes in postmenopausal women, with no adverse effect on the endometrium and vagina.


METHODS
A total of 389 participants met the parent study criteria and were randomly assigned to receive the phytoestrogen genistein (n = 198) or placebo (n = 191). About 40% of participants in both groups did not experience hot flushes, and the evaluation was performed in a subgroup of 236 participants (genistein, n = 119; placebo, n = 117). Reductions from the baseline in the frequency and severity of hot flushes were the principal criteria of efficacy. Endometrial thickness was evaluated by ultrasonography. The maturation value was also used to determine hormonal action on the vaginal cells.


RESULTS
There were no significant differences in vasomotor symptoms between groups at the baseline (4.4 +/- 0.33 hot flushes per day in the genistein group and 4.2 +/- 0.35 hot flushes per day in the control group). After 12 months of genistein therapy, there was a significant reduction (-56.4%) in the mean number of hot flushes, with a significant difference compared with the control group. After 24 months, there was no further decrease in the number of hot flushes in both groups. No significant difference was found in mean endometrial thickness and the maturation value score between the two groups, either at the baseline or after 24 months.


CONCLUSIONS
The phytoestrogen genistein has been shown to be effective on vasomotor symptoms without an adverse effect on the endometrium and vagina, but after the first year, there was no further improvement in the decrease in hot flushes.
D'Anna
Rosario
R
Department of Obstetrical and Gynaecological Sciences, Section of Pharmacology, AOU Policlinico G Martino, Messina, Italy.
Cannata
Maria Letizia
ML
Marini
Herbert
H
Atteritano
Marco
M
Cancellieri
Francesco
F
Corrado
Francesco
F
Triolo
Onofrio
O
Rizzo
Piero
P
Russo
Silvia
S
Gaudio
Agostino
A
Frisina
Nicola
N
Bitto
Alessandra
A
Polito
Francesca
F
Minutoli
Letteria
L
Altavilla
Domenica
D
Adamo
Elena Bianca
EB
Squadrito
Francesco
F
D004311:Double-Blind Method; D004717:Endometrium / Q000187:drug effects*; D004848:Epithelium / Q000187:drug effects; D005260:Female; D019833:Genistein / Q000008:administration & dosage; D019584:Hot Flashes / Q000188:drug therapy*; D006801:Humans; D008875:Middle Aged; D048789:Phytoestrogens / Q000008:administration & dosage*; D017698:Postmenopause; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014621:Vagina / Q000187:drug effects*
D048789:Phytoestrogens; D019833:Genistein