Mystiqueu 2009-11-21 03:40:36
Now I understand why **s** tourism** from Japan to Hawaii is so
popular among Japanese men.
Soy supplements cut sexual behavior in rats
17:45 14 November 03
NewScientist.com news service
Soy supplements can decrease normal sexual behaviour by as much as 70
per cent, a study of female rats has shown.
The rats were given a commercially available supplement in doses
similar to those taken by women. The findings suggest a possible
negative side effect for the supplements, which are becoming very
popular among US women.
Isoflavones, the key compounds in soy, are estrogen-like molecules.
Soy supplements are touted as a natural alternative to hormone
replacement therapy and recent warnings of the risks of HRT may boost
the numbers of women turning to the supplements.
The supplements do have other potential health benefits. Women in the
Far East, whose regular diet includes relatively large amounts of soy,
have much lower cancer rates than Western women.
But some studies highlighted possible downsides. Soy isoflavones have
been show to interfere with estrogen function in rats, decreasing some
of the brain molecules involved in social and sexual behaviour. And a
specific isoflavone called genistein prevents the tumour-fighting drug
tamoxifen from working in mice. The new study, showing that a soy
isoflavone has negative effects on sexual behavior in rats, joins
When female rats are on heat, they typically encourage nearby male
rats by changing their posture. Once a male rat has approached, they
change their position to be more receptive to their mate.
Heather Patisaul and colleagues at Emory University in Atlanta,
Georgia, gave female rats small doses of soy supplement. This produced
blood levels of the isoflavone similar those in women regularly taking
The “encouraging behaviours” in the rats decreased by 70 per cent,
while the “receptive behaviours” decreased by up to 40 per cent.
The breast cancer drug tamoxifen, which opposes the function of
estrogen in some tissue, had a similar but smaller effect. This, with
evidence from other studies, leads Patisaul to believe that the soy
isoflavone is also acting as an “estrogen opposer”.
She adds that there is anecdotal evidence of decreased s** drive in
women taking tamoxifen, as well as problems with vaginal dryness.
Patisaul does not know if any such side effects have been reported in
women taking soy supplements. But she notes that since most women take
them for menopause, it would be difficult for women to tell if changes
in s** drive were due to the pill or changing hormones.
“You would need to do a controlled clinical trial to sort it out,” she
says. “But no one has asked these women about sexual side effects. We
need to look at all aspects of what [these compounds] are doing.”
Andrew Kaunitz, at the University of Florida in Jacksonville and a
researcher with the women’s health initiative, agrees that this should
be looked into. “Interest in soy has increased in recent years,” he
The new study was presented on Wednesday at the Society for
Neurosciences meeting in New Orleans.
John de hoog 2009-11-21 03:41:52
(1) Soy supplements are not popular in Japan.
(2) Since both men and women eat plenty of soy daily, by your logic the men
should have no interest in s** tours.
I could also give you plenty of anecdotal evidence to counter this silly
John de Hoog