Caution
Urged on Soy
Menopause Remedies
LONDON (Reuters Health) - A researcher said on Tuesday that so
little is known about how plant oestrogens act on the human body
that sales of soy supplements as a natural alternative to hormone
replacement therapy (HRT) must be questioned.
Soy is being widely promoted as a natural alternative to HRT. This
is because it contains genistein, a plant oestrogen that has similar
but weaker effects to normal oestrogen found in women.
But Dr. Saffron Whitehead, reader in reproductive physiology
at St. George's Hospital Medical School, London, said new studies
on human cells have shown that genistein and other phyto-oestrogens
may also stop the enzymes that make these hormones.
She told the British Endocrine Society's annual meeting in Harrogate,
Yorkshire, this could explain why the incidence of breast cancer,
which in many cases is dependent on oestrogen, is about two-thirds
lower amongst Japanese and Chinese women who consume diets rich
in soy compared with women living in England.
Whitehead's team examined the effects of phyto-oestrogens on
human ovarian cells obtained during procedures for in vitro fertilization.
The results showed that several phyto-oestrogens, including
genistein, inhibited the conversion of androgens to oestrogens.
The researchers believe this could be significant in postmenopausal
women because as these women's ovaries cease to function, their
only source of oestrogens is converting androgens released by
their adrenal glands.
"This finding is potentially important to the phyto-oestrogen
story," Whitehead added in a statement. "We really don't know
how phyto-oestrogens act in the human body. They could be weak
oestrogen mimics, oestrogen blockers or enzyme inhibitors.
"If they do stop the natural production of oestrogens, we should
consider whether soy supplements be sold as a natural alternative
to HRT."
Reference Source 89
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