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From
Pink Pills to Phytoestrogens – spot the difference Womens Health Watch September/October 1998. At
the turn of the century Dr Williams Pink Pills for Pale People,
three shillings a box, were touted as relieving menstrual problems.
Analysed, they turned out to contain one tenth of a penny’s
worth of nothing very much, coated in starch and sugar. Middle-aged
women eyeing today’s over-the-counter remedies might wonder
whether they are being offered Pink Pills – or more potent
nostrums. Two Auckland scientists warn that products like
Red Clover Pills (and equivalent pills targeted at men with prostate
problems) are not only outrageously priced, but possibly harmful.
One health product manufacturer says he is ‘seriously worried’
about these profitable plant or phytoestrogen pills (his estimate
of the cost of $30 month’s supply is a couple of dollars).
Auckland environmental consultant and phytoestrogen researcher Dr
Mike Fitzpatrick is concerned too. The phytoestrogens in red
clover disrupt the endocrine system and suppress thyroid hormone
synthesis, he says, as well as causing genetic damage to cells.
They are also potential carcinogens. But
there is big money to be made in the hormone replacement therapy
market, and natural HRT is the latest craze, he says. ‘But
where is the research to back up the health claims and where are
the guarantees of consumer safety? They have done less research
than they would on cats and dogs if this were a veterinary medicine.
If the New Zealand government is willing to let manufacturers of
phytoestrogen products make medicinal claims, then those claims
should at least be backed with the kind of research I hope goes
into medicinals.’ But
they don’t have to be. Because phytoestrogen ‘dietary
supplements’ are classified as foods, not drugs, they are virtually
unregulated. They can be sold that way so long as no therapeutic
claims are made. Even when claims are made (in press and television
advertising), the Ministry of Health seems reluctant to clamp down. The
labels on phytoestrogen supplements may bear coy messages like ‘considered
valuable in balancing female hormone levels’, but other promotional
material is more explicit. Often the pitch is that phytoestrogen
pills are hormone replacement therapy substitutes – only natural
and better. In case you don’t get the message, the products
are called HRT – standing for Herbal Replacement Tablets –
described as made from extracted plant substances that ‘work
in harmony with the body’, that just nudge natural processes
along. Blackmores
have sent out a laminated ‘clinical guide’ to GPs, suggesting
that the possible clinical applications for their products include
hyperlipidaemia and heart disease, cancer prevention, menopause,
osteoporosis and renal disease and offering the reassurance that
‘there has been no evidence of human toxicity from individual
isoflavones in the doses thus far used in human trials.’ The
claim of safety is carefully phrased – and with good reason.
Red clover pills are, after all, made from a variety of clover that
continues to render grazing sheep infertile, less sexually receptive
and more aggressive. Clover estrogens (and soy estrogens when
sheep forage on that plant) can cause ovarian cysts and irreversible
endometriosis in ewes, and blocked urethra, enlarged teats and lactation
in wethers (castrated rams). First
alerted to the sheep problems in Australia in the 1940s, scientists
came to understand that phytoestrogens serve as a plant’s natural
defence against grazing animals. When plants like red clover
are stressed (by drought, or even by spraying with herbicide) higher
levels of estrogens are produced. By mimicking mammalian estrogens,
plant estrogens diminish the fertility of predators and so protect
the plants. Phytoestrogens
in clover were a curse for sheep farmers. The implications
for humans were glancingly considered by scientists- but not to
worry, since these plant estrogens were not a significant part of
our diet. Neither were they in the 1940s. But 50 years
on the phytoestrogen-laden soybean has entered the Western foodchain
in a big way. Despite
the experience with sheep (and decades of worrying animal studies)
not a single long term study has been undertaken on the effects
of dietary phytoestrogens on humans. No one has any real idea
of the chronic toxicity of these compounds. Yet over recent
decades the food industry has been discreetly adding estrogenic
soy to basic foodstuffs – including bread, pasta, sausages,
and even frozen chicken pieces (check for the ingredient labelled
‘vegetable protein’). The
adulteration is now more overt, with phytoestrogen sold as dietary
supplements, added to some breads and breakfast cereals, and soon
to be put in margarine, muesli bars, biscuits and drinks.
The time to take notice is overdue. Some of our daughters,
particularly if vegetarian, may well be consuming plant estrogens
at biologically active levels. So
just how powerful are these compounds? Is there anything to
worry about? When Dr Fitzpatrick analysed processed foodstuffs
for phytoestrogen levels several years ago, he thought so.
In 1995 he and three other researchers warned in the New
Zealand Medical Journal that soy infant formula, for instance,
contains three to five times as much phytoestrogen as has been shown
to disrupt the menstrual cycle of women. The scientists recommended
that supermarket sales of this formula be stopped – advice
not so far heeded by our health ministry, although discussion is
ongoing. Dr
Fitzpatrick says his concerns about these new supplement products
are shared by US FDA estrogen research director, Dr Dan Sheehan,
who only last April warned against adding phytoestrogens to foodstuffs. ‘Phytoestrogens
can act on different sites of the body in different ways,’
says Dr Fitzpatrick. ‘There are too many unanswered questions
about them. What if a young baby gets hold of these pills?
Or a young girl going through puberty? Where are the warnings?’ There
is no denying these products are potent. One herbal product
containing plant estrogens called Evanesce is so potent it is widely
used in the US by men wanting to change sex and grow breasts.
(‘I’m now into a full B… it is to the point where
my wife and I know that I need to start wearing a bra’ is the
testimonial of one satisfied customer.) But
quite what the effects are on middle-aged women is not so clear.
Nor is it clear what dose of these products is safe to use, or what
age group can use them. Even sticking to low doses is no protection,
says Fitzpatrick, since scientists have little knowledge about dose-related
responses in humans and there is individual variation in susceptibility. Fitzpatrick
is not reassured by reminders that the Japanese consume soy safely,
saying that recent data shows their average daily phytoestrogen
intake is lower than previously thought – less than the amount
that an infant on soy formula consumes. What
if you are getting a lot of phytoestrogens in your diet already?
By taking these pills you may be doubling the dose. Where
is the warning that a vegetarian diet or even a litre of soymilk
already provides enough
phytoestrogen to elicit a biological response. You can be
sure that there will be a level at which phytoestrogens become acutely
toxic, never mind the chronic effects associated with continued
daily exposure.’ Asked
about the long-term effects, Fitzpatrick shrugs. ‘We
just don’t know. But it was established in the 1940s
and 50s that estrogens are bad news long-term. There is more
awareness now that these exogenous estrogens can promote cancer
and cause endocrine disruption.’ Overseas,
concerned researchers and regulators warn that manufacturers are
jumping the gun, seizing an apparent marketing opportunity before
safety has been established. US
phytoestrogen researcher Dr Claude Hughes has warned women to consider
‘whether they or their offspring will experience any reproductive
or developmental effects due to exposure to these dietary hormone-like
phytochemicals.’ One
US study has shown a link between tofu consumption in mid-life and
dementia – possibly attributable to phytoestrogens affecting
estrogen sensitive brain cells. In
1996 a British government committee concluded that ‘the potential
for phytoestrogens to adversely affect infants is of particular
concern since it is possible that a hormonal imbalance in early
life can permanently affect sexual development and fertility’.
Both that body and the US Environmental Protection Agency have called
for further research on these ‘endocrine disruptors’. Recently
the British Medical Research Council’s Institute of Environment
and Health researchers reviewed the scientific literature, looking
only at possible phytoestrogen benefits (reasoning that adverse
effects were already well established). Their 170 page report
released last November concluded that although some studies suggest
some phytoestrogen containing foods
may have health benefits, ‘almost no evidence exists to link
these effects directly to phytoestrogens’. As
for taking phytoestrogens in pill form, even an optimistic phytoestrogen
researcher like Dr Kenneth Setchell warns against them, saying ‘the
potential dangerous effects from self-induced megadosing are a concern’.
REFERENCES: Fundamental
and Applied Toxicology 1996; 29: 1-17, Clinical chemistry 1997; 43: 850,
Reproductive Toxicology
1989; 3: 81-90, Environmental
Health Perspectives 1988; 78: 171-175,
PSEBM 1995; 208: 92-97,
Institute for Environment and Health Nov 1997 Report
to MAFF on Phytoestrogens in the Human Diet, Lancet 1997; 350: 23-27, NZMJ 24 May 1995; 208-209 Statement by committee on toxicity of chemicals in food,
consumer products and environment (UK) 1996 |
