By Sue Claridge
Organic New Zealand, 2006, Volume 65 (July/August, Issue 4, pg 28-30 and September/October Issue 5 pg 27-32).
Environmental oestrogens are changing what it means to be a man or a woman, and are contributing to our chronic ill-health.
Oestrogen. None of us would exist without it. It is the primary female sex hormone. It is responsible for the normal, healthy growth and function of the female reproductive organs. Without it there would be no conception and there would be no pregnancy. But too much oestrogen, specially if it comes in unnatural forms, can cause serious health problems, not only for women, but also for men, children and our environment. And damaging exposure can occur as early as in the womb, impacting on the lives and health of our children before they are born.
Xenohormones and Endocrine Disruptors
The human endocrine system is made up of a variety of glands that secrete hormones (the pituitary, thyroid, ovaries, testes, adrenals, etc.) and receptor cells which detect and react to those hormones. Many hormones undergo transformations within the body and become different hormones. For example, both testosterone and oestrogen are produced from androgens which are originally synthesised from cholesterol, and the thyroid hormone T4 is converted to T3 in the liver.
Hormones are vitally important and precise chemical messengers; they control or regulate many bodily functions and processes. Specific hormones interface with cells that have matching receptors – fitting like a key into a lock - and they signal these cells to alter their growth, function, or metabolism.
Endocrine disruptors or xenohormones are exogenous substances – substances from outside the body that can bind with or block hormone receptors, disrupting or mimicking the production or action of our own hormones.
The most obvious example is the contraceptive pill. Synthetic versions of oestrogen (sometimes with synthetic progesterone) trick the body into stopping the release of eggs each month, thereby preventing pregnancy. Unfortunately, oestrogen used in this way has other effects, such as weight gain and mood changes, because oestrogen has a number of functions and roles within the body and takes part in regulating a number of systems.
However, there are a plethora of other compounds and chemicals that can either mimic or block the action of endogenous hormones. And unlike the contraceptive pill, we don’t ingest them deliberately or with the intention of altering our internal chemistry.
While there are many endocrine disrupting chemicals, xenoestrogens are one of the most important. They are insidious, entering our bodies without our knowledge and, at least at first, subtly having an impact on the ways that our bodies function. These xenoestrogens are all around us, in our food, our personal products and cosmetics, in the plastics that wrap our food, the bottles we drink from. They make their way into our waterways to impact on aquatic fauna. And they contribute to or cause infertility and other reproductive problems, thyroid dysfunction, weight gain, breast and prostate cancer and a host of other symptoms and illnesses.
Insidious Sources – where are the dangers?
There are many, many chemicals and chemical compounds that mimic or affect oestrogen in our bodies. The list below contains some of the known oestrogenic substances to which we are exposed on a regular, if not daily, basis. It is by no means comprehensive, and the oestrogenic effects of more chemicals are being discovered all the time.
Three of the most common xenoestrogens are the bisphenol A, phthalates and parabens. Unlike some of the substances and products that we readily associate with adverse effects on our health and well being – pesticides, dioxins, heavy metals, etc. – parabens, bisphenol A and phthalates are found in everyday items: our food and food containers, plastics, cosmetics and personal care products, toys. Even in drugs and medical equipment!
Xenoestrogens in Your Kitchen
Bisphenol A (BPA) is the base for an entire sector of the plastics industry; it forms the polycarbonate plastic used in some baby bottles and toddlers’ sippy cups, food can linings, dental sealants,
and sports water bottles as well as many food containers and plastic packaging, and clear polycarbonate “glasses”. Recent studies show that bisphenol A leaches from intact polycarbonate products as well as from worn or damaged plastic.
The impact on our health starts as early as in the womb. Concerns about BPA were initially raised in 1997, when Dr Fred vom Saall, a developmental biologist at the University of Missouri-Columbia, discovered that mice fed low doses of the chemical while pregnant gave birth to male pups that developed enlarged prostates.(1)
In their 2005 review of the literature(2), Drs vom Saall and Claude Hughes wrote that, as of December 2004, there were “115 published in vivo studies concerning low-dose effects of BPA, and 94 of these report significant effects.”
Those 115 papers detailed an horrific array of effects that have enormous impacts on our sexual and physical development, fertility, behaviour and brain function as a result of both foetal, childhood and adult exposure to BPA:
increased postnatal growth in both males and females;
early onset of sexual maturation in females, altered plasma luteinising hormone levels*, and disruption of adult oestrous cycles;
increase in prostate size in male offspring and decrease in daily sperm production and fertility in males;
stimulation of mammary gland development in female offspring;
significant disruption of the alignment of chromosomes during meiosis in developing eggs during puberty due to leaching of BPA from polycarbonate drinking bottles;
an increase in mortality of embryos as a result of maternal exposure;
altered immune function;
changes in the brain progesterone and somatostatin receptors;
behavioural effects including hyperactivity, an increase in aggressiveness, altered reactivity to painful or fear-provoking stimuli, and impaired learning;
decreased maternal behaviour, altered play and other socio-sexual behaviours, and enhanced behavioural response to drugs such as amphetamine.
In research published in January 2006, Spanish scientists found that BPA caused the pancreas to secrete insulin, with repeated exposure to BPA causing insulin resistance(3). The researchers said that oestrogen receptors in the pancreatic-cell nucleus appear to contribute to this effect.
Although this article focuses on the oestrogenic effects of BPA it is important to understand that the impact doesn’t end there. Vom Saal and Hughes also found research indicating that BPA has the potential to disrupt thyroid hormone action, cause proliferation of human prostate cancer cells by binding to a mutant form of the androgen receptor, and can also block testosterone synthesis(2).
The concern is not only over our exposure to BPA through consumer products. Studies in Japan and the US “have shown that BPA accounts for most oestrogenic activity that leaches from landfills into the surrounding ecosystem.”(2) BPA is damaging our wildlife and is in our drinking water!
Phthalates (said thā-lates) are as ubiquitous as bisphenol A. Made from petroleum by-products, phthalates are used plasticisers to make rigid plastics pliable, as solvents and in adhesives, waxes, inks, cosmetics, insecticides and drugs. They are found in vinyl flooring, detergents, automotive plastics, soap, shampoo, deodorants, fragrances, hair spray, nail polish, plastic bags, food packaging, garden hoses, inflatable toys, blood-storage bags, and intravenous medical tubing. Phthalates are even used to coat pills to make them easier to swallow or to control how they dissolve, and it is almost beyond belief that these compounds are used in baby “chew” toys to keep them soft.
Like bisphenol A, the impact of phthalates on our development and our health starts before our children are born. In July 2005, Dr Shanna Swan and colleagues published the results of a study into cosmetic use and the feminising of baby boys. The Environmental Health Perspectives (EHP) paper(4) announced that baby boys born to women who had a high phthalate metabolite concentrations in their urine were more likely to have undescended testicles, smaller penises and a shorter ano-genital measurement. This measurement – the distance from the base of the penis to the anus – is one of the most sensitive indicators of the demasculinisation of baby boys.
Frighteningly, this level of phthalates in the body is not unusual. The concentration of phthalate metabolites found in the mothers of the affected babies was comparable to those found in one-quarter of the US female population. Several other studies, cited in the EHP paper, have said that phthalate concentration in humans is fairly stable, reflecting habitual use of phthalate-containing household and consumer products.
Another 2005 study investigated the impact of phthalates in human breast milk. Among baby boys in Denmark and Finland those whose mother’s milk had higher levels phthalates had less testosterone during their crucial hormonal surge at three months of age than baby boys exposed to lower levels of phthalates(5).
These studies cap a plethora of research demonstrating the effects of phthalate exposure on the reproductive health of both animals and humans. Several studies that have shown that in utero exposure to phthalates compromises the sexual development of male rats and causes malformations of the reproductive tract that persist into adulthood, and others have shown that:
phthalates disrupt male rat sexual differentiation by reducing testosterone to female levels in the foetal male rat during a critical stage of reproductive tract differentiation(6);
premature breast development in girls is associated with high serum concentrations of phthalate metabolites(7);
low sperm count or low sperm activity, and abnormally shaped sperm were found in men with the highest concentration of phthalate metabolites in their urine(8);
urinary monoethyl phthalate at environmental levels, is associated with increased DNA damage in sperm(9);
phthalate ingested by mother rats caused gene alteration in the pups exposed in utero(10);
three types of phthalates – BBP, DBP and DEHP – significantly increase cell proliferation in MCF-7 breast cancer cells(11).
Parabens in various forms (methyl-, ethyl-, propyl-, butyl-, etc.), are used as preservatives in a wide range of cosmetics and pharmaceuticals including shampoos, moisturisers, shaving and cleansing gels, creams, lotions and antiperspirants and deodorants. They are also used as preservatives in some foods.
Despite the fact that parabens are used in an estimated 13,200 cosmetic formulations(12) and are, in many cases, liberally applied to our skin, there is a lack of safety data on this group of chemicals and cosmetics are not regulated in the way that food and pharmaceuticals are. The Environmental Defense website, Scorecard (www.scorecard. org), reveals that there is a lack of data that would enable a proper safety assessment of parabens, and the final report on the safety of parabens in cosmetics was published in 1995, before evidence of the endocrine, reproductive and developmental effects of parabens had been reported.
A substantial amount of research on the oestrogenicity of parabens has been conducted over the last eight years. A 1998 paper by Dr Edwin Routledge, and his colleagues in the UK, found that subcutaneous administration of butylparaben produced a positive uterotrophic response in immature rats(13). They wrote that “given their use in a wide range of commercially available topical preparations, it is suggested that the safety in use of these chemicals should be reassessed, with particular attention being paid to estimation of the actual levels of systemic exposure of humans exposed to these chemicals.” Subsequent
research found that oestrogenic activity of parabens increases with increasing length of the linear alkyl chain from methylparaben to n-butylparaben.
Dr Philippa Darbre et al., reviewed the research in their 2003 paper in the Journal of Applied Toxicology(14); in summary that research found that specific parabens have been shown to:
bind to rodent uterine oestrogen receptors;
bind to oestrogen receptors from MCF7 human breast cancer cells;
regulate the expression of the endogenous oestrogen-regulated genes pS2 and progesterone receptorin breast cancer cells;
increase the growth of MCF7 human breast cancer cells;
increase uterine weight in immature rats and mice.
In line with research on the effect of other xenoestrogens on male rats, Korean research published in 2002, found that the weight of testes, seminal vesicles and prostate glands were significantly decreased in rats exposed to butylparaben and that the sperm count and the sperm motile activity were also significantly decreased(15).
In 2003, Darbre proved that parabens could be absorbed through the skin and mimic oestrogen having done so(16), and in 2004 her research found accumulations of parabens in human breast tumour tissue(17), although her study did not address whether or not the parabens had contributed to the development of the tumours. She reported that methylparaben was detected in the greatest amounts possibly reflecting the widespread use of methylparaben in consumer products; methylparaben had earlier been shown to be oestrogenic in human breast cancer cells(18).
In the first part of this article we looked at the role of oestrogen and our exposure to exogenous forms of this hormone. While we can’t function or procreate without the natural human form of oestrogen, compounds that mimic oestrogen in the body are causing a catastrophic catalogue of health problems. These xenoestrogens are found in many day to day items that have become a ubiquitous part of our modern lives. In this follow-up we will consider just what implications this constant and escalating exposure has for us as a population.
Extreme Oestrogens – in our Sunscreens!
The bad news doesn’t end with our daily exposure to bisphenol A, phthalates and parabens. One of the most sexed-up and hormonally toxic brews that we are exposed to is one that we are encouraged to slip, slop and slap all over ourselves and our children almost from the moment of birth.
Vigourously promoted and used by even our youngest, most vulnerable children, that sunscreen that you rub onto every bare bit of skin may contain a nasty surprise. Many sunscreens contain one or more oestrogenic compunds (some chemical UV screens and parabens are estrogenic). It is plastered regularly (often several times daily) over large areas of skin and is absorbed in order to prevent UV rays from damaging the skin. But is there a potentially greater damage in exposing our children and unborn babies (not to mention oursleves) to regular doses of these xenoestrogens?
A team of Swiss researchers from the Institute of Pharmacology and Toxicology at the University of Zurich, led by Dr Margret Schlumpf, found that five out six commonly used UVB and UVA radiation screens showed oestrogenic activity (see table below). These are found in concentrations of up to 10% in sunscreen products and are also added to other cosmetics for product stability and durability.
Xenoestrogens and the Environment
Estrogens are finding their way into our environment in ever increasing quantities. And they are not inert, sitting their having a negligible or non-existant effect. In fact, as usual, our environment, particularly aquatic fauna are acting as our canaries in the coal mine and are showing just how catstrophic the impact of these chemical endocrine disruptors can be.
The journal Environmental Health Perspectives reports that “reproductive and developmental abnormalities linked to [endocrine disrupting chemical] exposures have now been documented in birds, frogs, seals, polar bears, marine mollusks [sic], and dozens of other wildlife species.”(19) The adverse effects of these chemicals include the feminising of male animals, (shortened penises and low levels of testosterone), excessive oestrogen in female animals, sex reversal in which an animal of one sex matures with the reproductive organs and capabilities of the other sex, and skewed sex ratios in which there is an unusually greater proportion of one sex than the other.
Professor of cell biology and neuroscience at Rutgers University, Dr Joanna Burger, said that “the weight of evidence for endocrine disruption in wildlife is really overwhelming,”(19) and according a report she co-edited on endocrine active substances (EAS) “over 200 species are either known or are suspected to have been affected by EASs.”(20)
Epidemics of Chronic Ill-health – the implications for our species
Individually the potential impact of xenoestrogens on the health is bad enough, but the implications for the health of our species enormous. The incidence of breast cancer is constantly on the rise in the developed world, prostate cancer is the most common cancer in New Zealand men and the third biggest cancer killer in men, there is a burgeoning epidemic of obesity, girls are experiencing the onset of puberty at ever younger and fewer baby boys are being born. What role do xenoestrogens play in these issues?
We are constantly bombarded with reports on the burgeoning obesity epidemic and the impact that being overweight or obese has on our health and our on mortality and morbidity statistics. Obesity is largely blamed on increasing consumption of calory-dense processed food and sedentary lifestyles. However, this may only be part of the picture. High insulin levels cause excess glucose to be stored as fat, and the removal of glucose from the bloodstream causes a sudden drop in blood sugar, leading to hunger and a desire for food that provides a rapid energy boost, which in turn triggers the release of more insulin.
Two studies linking exposure to oestrogens to insulin secretion and insulin resistence were published in May 2005: researchers from King's College in London found that the 17-beta-estradiol, the synthetic estrogen used in the contraceptive pill, initiated insulin secretion(21), and Japanese scientists found that long-term exposure to endocrine disrupters, such as BPA and nonylphenol, promotes in vitro insulin secretion from the rat pancreatic islet cells(22).
In January 2006 researchers published the results of another study in which they found that repeat exposure to BPA caused insulin resistance in mice. The mice went onto develop chronic hyperinsulinemia**, and their glucose and insulin tolerance tests were altered(23). Dr Angel Nadal of Miguel Hernández University in Spain, who led the study, said that this research might partially explain the global epidemic of diabetes. Dr Frederick vom Saal of the University of Missouri–Columbia called the research a "wake-up call" for public health researchers who are concerned by the prevalence of diabetes.
That estrogen has a role in the development of breast cancer is well known. Some breast cancers are estrogen receptor positive, but even women whose tumours that are estrogen receptor negative, esrtrogen plays a part. Estrogen stimulates breast development and breast cell division. Girls and women are particularly vulnerable to estrogen at three critical times in their life – in the womb, at puberty and during pregnancy – and excess exposure to xenoestrogens at these times may trigger subsequent breast cancer.
We saw in part one that BPA, phthalates and parabens have all been associated with either premature breast development or the proliferation of breast tumour cells.
In some of the latest research, low, environmentally relevant doses of BPA caused large increases in the number and density of terminal end buds in baby mice exposed to BPA in the womb. These parts of the mammary gland structure are where breast tumours originate in both animals and humans. In addition, the baby mice showed a decreased ability to get rid of damaged cells that could be cancerous.
The researchers, whose study was published in the journal Endocrinology(24), concluded that their studies “suggest that perinatal exposure to BPA in particular, and to estrogens in general, may increase susceptibility to breast cancer.”
Dr Theo Colburn, from the Endocrine Disruptor Exchange in the US, says that “because total estrogen exposure is the single most important risk factor for breast cancer, estrogenic chemicals, which would add to this lifelong exposure, are an obvious suspect when searching for the cause of rising rates (of breast cancer) over the past half century.”(25)
Oestrogen is generally seen as being a “women’s issue” but research has shown that, particularly for male foetuses, exposure to environmental oestrogen can have long term and significant adverse impacts for men. Numerous studies have shown that oestrogenic chemicals can impact on the the male reproductive tract as a result of perinatal exposure to these substances; the impacts on baby boys includes increases in the size of the prostate. The implications for the increasing incidence of prostate cancer are clear, and have been substantiated by research carried out in the last five years.
Wetherill and colleagues reported in 2002 that very low part-per-trillion doses of BPA cause proliferation of human prostate cancer.(26) These cancer cells were also less responsive to the standard hormone treatment used to put prostate cancer into remission.
Scientists from the University of Cincinnati and University of Illinois exposed newborn rats to low doses of BPA and found that the structure of genes in their prostate cells was permanently altered, a process of reprogramming in early life that promotes cancer in adulthood(27). As the rats aged they were more likely to develop precancerous lesions in the prostate, that in humans has been known for years to lead to prostate cancer.
The research hers told The Los Angeles Times that the study’s "findings provide the first evidence of a direct link between developmental low-dose bisphenol A ... and carcinogenesis of the prostate gland.”(28)
A US researcher not involved with the study, Dr. Rebecca Sokol who specialises in male hormone research, said that the was "cutting-edge" and that it “added to a growing body of research, called epigenetics, that suggested environmental chemicals could alter how DNA sequences turned on and off in a fetus, permanently imprinting the genes of a child and sensitising him or her to disease in adulthood.”(28) She said that BPA seems to inflict subtle changes in the DNA that are passed from one generation to the next.
Clearly this research raise questions about the ongoing impact of xenoestrogens – we should not just be worried about the adverse effect on the individual but potentially negative impact on generations to come.
Puberty Comes Early
The average age at which girls experience puberty has got steadily younger in the last couple of decades. In the late 19th and early 20th centuries the average age for the menarche was 17; by the 1960s and 70s it was 12 or 13. Now girls as young as nine starting their periods is common and the associated breast development is occurring even younger: research published in the journal Pediatrics in 1997 found that at the age of three years, 1% of Caucasian American girls had started breast and/or pubic hair development. At the age of eight this had increased to almost 15%. The rate was higher among African-American girls, and xenoestrogens could be at least partly to blame.
The authors of the 1997 study that "the possibility that the increasing use of certain plastics and insecticides that degrade into substances that have estrogen-related physiological effects on living things should be investigated in relation to the earlier onset of puberty.”(29) Specifically, they talked about DDE (from the pesticide DDT), bisphenol A, and phthalates.
Numerous other studies have linked early sexual maturity in animals and humans to exposure to oestrogenic chemicals. In one, scientists found that girls with the highest pre-natal exposures to PCBs and DDE hit puberty eleven months earlier than girls with lower exposures(30).
In another study, African-American girls aged 14 months to seven and a half years developed breast or pubic hair two to 24 months after starting the use of estrogen or placenta-containing hair products. When use of the hair products was discontinued there was regression of the breast or pubic hair(31).
There are a number of implications for health across the population as a result of girls entering puberty earlier. Girls who reach puberty early have an increased risk of breast cancer later in life because of their exposure to their own oestrogen through a greater number of menstrual cycles.
In addition, Dr. Gilbert August, a paediatric endocrinologist in Washington D.C., is concerned about the psychosocial implications of early puberty: "From a psychosocial standpoint, you have a child who looks sexually mature at an age where they can't make judgments associated with their physical appearance,” he says.
And finally, when children hit puberty their intellectual development slows as sexual development take precedence. If this is occurring at increasingly younger ages it is easy to see that intellectual development could be curtailed which, across an entire generation, has implications for us as a species. Are xenoestrogens damning human beings to a downward spiral in our intellectual capacity?
The ratio of baby girls to baby boys born each year around the world is fairly constant typically ranging from 102 to 108 male births for every 100 female births(32). However there have been a number of reports that indicate that exposure to endocrine disrupting chemicals may be altering the natural ratio of baby boys and girls. Given the studies that have shown that xenoestrogen exposure is linked with malformations of the male reproductive tract and changes in sperm quality and quantity this should probably not come a surprise.
Researchers investigating a decline in the birth of male babies in the Chippewa people of the Aamjiwnaang reserve near the Great Lakes in Canada found that between 1993 and 2003 male babies made up only 41.2% of live births, while in the five year period from 1999 to 2003 male babies made up only 34.8% of live births compared with the national Canadian average of 51.2%.(32)
The Aamjiwnaang reserve is next several large petrochemical, polymer, and chemical industrial plants, and soil and sediment testing revealed high concentrations of PCBs, HCB, mirex, polycyclic aromatic hydrocarbons, heavy metals, and phthalates, dioxins and furans, and vinyl chloride, many of which are known endocrine disruptors.
In addition, previous research has shown that wildlife populations in the Great Lakes close to the Aamjiwnaang reserve have been adversely affected: fish with both male and female sexual organs, reduced hatching success and altered sexual development in turtles and changes in the sex ratios of birds.
So, what is anyone doing about it?
Those speaking in defence of these chemicals, usually people with a vested financial interest in their continued manufacture and use, say that studies have shown that high dose exposure to oestrogenic chemicals cause no harm to humans.
Typically, both the plastics and cosmetics industry associations in New Zealand deny any harm from these substances.
Plastics New Zealand, the plastics industry association, say on their website (www.plastics.org.nz) that “consumers have been unnecessarily concerned by recent reports” and that “contrary to some recent reported comments polycarbonate is totally safe in its common applications as a versatile engineering and packaging material, even when these uses involve long-term food contact.” They go on to attack the research that has been done on the oestrogenic effects of BPA in a way that is typical of such industry websites in other countries, saying that the scientists who carry out the research are not polymer chemistry experts, as if that is prerequisite for analysing epidemiological and in vitro laboratory data.
The Cosmetic Toiletry Fragrance Association website (www.ctfa.org.nz) also denies that phthalates used in cosmetics and personal care products are of any concern. They say that : “there have [sic] been some minor research which indicated that further research was necessary to establish where there was any issues however there is no scientific data to establish any danger.” Their claim that “recent official scientific findings in the EU and the US have shown that even in higher consentrations [sic] such as those used in vinal [sic] toys, they are safe for infants through to adults,” directly contradicts recent research and concerns expressed by the World Health Organisation (see below).
In findings that mirror the pharmaceutical industry, Dr Frederick vom Saal in a review of 115 studies on bisphenol A, found that, although more than 90 percent of the studies conducted by independent scientists found significant adverse consequences, none of the 11 industry funded studies reported any significant effects(33).
And some countries are banning the use of these chemicals in some products despite industry efforts to allay fears.
The Wall Street Journal reported that “in 2003, Japan banned certain types of phthalates in food-handling equipment after traces turned up in school lunches and other foods.”(34)
The October 2005 article went on to say that “the European Union has recently banned some phthalates in cosmetics and toys. In January, the European Parliament's public health committee called for banning nearly all phthalates in household goods and medical devices. In July, the full parliament asked the EU's regulatory body, European Commission, to review a full range of products 'made from plasticised material which may expose people to risks, especially those used in medical devices.' ”
In 2005, a bill was put before the Californian Legislature that would have banned toys, pacifiers, baby bottles and teethers that contained BPA or phthalates. The bill sparked considerable debate and was defeated in an appropriations committee on January 19, 2006, after sparking a scientific debate and intense lobbying by the plastics industry.(28) The failure of the bill came only three days before the Israeli Ministry of Health warned that parents should throw away old or cracked baby bottles, and worn pacifiers and teething rings because of the dangers of BPA leaching into baby formula or being ingested directly from worn plastic(35).
And In New Zealand?
Neither of New Zealand’s two main political parties made any mention of endocrine disruptors, xenoestrogens or environmental oestrogens, their effects or potential impacts on the environment or human health in their policies. The closest we get to any expression of concern was a vague mention in Dr Jackie Blue’s maiden speech to parliament in November 2005 in which she referred to the “growing body of evidence supporting the influence of foreign oestrogens which are found in some herbicides, chemicals and pharmaceuticals” and the development of breast cancer(36).
Not surprisingly, the Green Party are the only party that mention endocrine disrupting chemicals on their website, and they specifically address this issue, including specific policy on the prevention of breast cancer which includes mention of endocrine disrupting chemicals.
So what are our government agencies doing about this issue?
John Reeve, Principal Advisor, Toxicology, with the New Zealand Food Safety Authority (FSA), says that the FSA is aware of the research on xenoestrogens, but the FSA has no plans to suggest limiting the use of BPA in plastics used for food packaging and storage. He says that the FAS maintain a watching brief and are in contact with other countries with regard to any potential risk from xenoestrogens. He doesn’t believe that any of BPA, phthalates and parabens are of any concern and questioned the validity of the science that says they are. Like others defending the use of these chemical, Reeve, claims that doses to which we are exposed are too low to have any effect.
However, it seems that it is the low dose exposure that is causing the damage. According to Wade Welshons of University of Missouri–Columbia’s College of Veterinary Medicine, the endocrine system is designed to respond to small, subtle changes in hormone concentrations – far below doses used in traditional toxicity testing, and typical of the sorts of low doses we are exposed to every day of our modern lives.
Reeve also said that the World Health organisation, in their own research, has found there is no evidence that xenoestrogens have any adverse impact on human health. However, that is not what the WHO’s report, Global Assessment of the State-of-the-Science of Endocrine Disruptors, said. They found that while “there is weak evidence that human health has been adversely affected by exposure to endocrine-active chemicals” the classification of the evidence as weak “is not to downplay the potential effects of EDCs; rather, it highlights the need for more rigorous studies.” Which is somewhat different from Reeve’s assertion.
Given the extensive research on envirmental oestrogens and other endocrine disrupting chemicals one has to ask “why are our Government and regulatory agencies not taking this threat seriously?”
Ernie Hood, in his paper “EDCs Blurring Issues of Gender?” writes that “if low-dose exposures were confirmed to be the threat that proponents of the concept insist they are, public health would clearly be at risk, regulatory agencies’ risk assessment approach would need to be revised, and certain common chemicals – including some that are massively produced and economically important – would likely disappear from the marketplace.”(37)
Herein lies the answer. Money! The industries that make and use these compounds are some of the biggest global companies on the planet and earn huge amounts of money for their shareholders and governments. Those in regulatory positions capable of doing something, by and large accept industry funded studies that show there is no harm, and ignore the considerably greater volume of independent research that says there is.
At least New Zealand’s Ministry for the Environment (MfE) are doing something about finding out more about EDCs. When approached for comment they advised that they are “gathering the most comprehensive information possible to assess the threat of endocrine disruptors in New Zealand.”(38)
They also say that they are monitoring developments in Europe where the issue of endocrine disruptors in the environment is a growing problem. And although one has to be concerned that it is a growing problem here, given that we use the same plastics, cosmetics, pesticides and plethora of other products that contain EDCs, the MfE believe that the “conditions which appear to be causing concern overseas” are not matched in New Zealand.
However, Dr Paul Hofman, a paediatric endocrinologist at Starship Children’s Hospital believes that xenoiestrogens and EDCs are a huge issue. “I am quite strongly of the opinion – and it’s opinion only, the science is just starting to come through – that this is going to be a very important problem.”
He isn’t concerned about theses substances having an impact on early puberty and thinks much of the early puberty statistics could be explained by methodology and cultural factors. However, Dr Hofman has considerable concerns about the other impacts of xenoestrogens, particularly exposure in the womb and the impacts that this has on metabolic pathways after birth. “In utero exposure may well be more important than exposure after birth,” he says.
“Bisphenol A, in particular, I think is a very scary compound. All our plastic cups, and the inside of aluminium cans is covered in the stuff…”
He sees a strong association between the tobacco iundustry and the plastics industry: “It’s a thousand billion dollar industry, they are going to fight this research tooth and nail.”
“The data is not yet as strong as with the tobacco industry,” he goes on, “but, it’s becoming quite persuasive.”
“The research is showing that there are adverse effects of these compounds at very low doses, probably doses that a lot of us can’t escape if we have any sort of plastic in the house.”
As usual it seems that New Zealanders will have to rely on the Green Party to get some politcal movement on this issue. They want a nationwide a breast cancer prevention strategy that specifically addresses the issue of xenoestrogens and would include “an independent study into whether exposure to oestrogenic chemicals is contributing to our breast cancer epidemic,” and “an evaluation by ERMA of all pesticides, building materials, cosmetics, household and consumer products for their ability to cause breast cancer or mimic oestrogen and a phase out of identified endocrine disruptors.”
But don’t expect that to happen anytime soon. The National Cancer Control Strategy makes no mention of EDCs or xenoestrogens and when, in 2003, Sue Kedgley asked then Health Minister, Annette King, to amend the Cancer Control Strategy to include mention of these chemicals, and “for the law be amended to require these chemicals, which are contained in everyday products, to be disclosed on a government website,” Ms King “did not seem to be acquainted with the risks of hormonally active or endocrine disrupting chemicals which are found in our food, water, air and household chemicals.”(39)
It seems nothing has changed since then. In researching these articles I made numerous requests to speak to someone in the Ministry of Health about xenoestrogens and endocrine disrupting chemicals; all these requests were fruitless, and no-one that I managed to speak to seemed to know what xenoestrogens and EDCs were. Sue Kedgley advised in May this year, that the National Cancer Control Strategy still makes not mention of xenoestrogens or EDCs.
Where To From Here?
Our ability to move forward technologically exceeds our ability to perceive the potential dangers. Bisphenol A was originally synthesised in 1891 and investigated as a synthetic oestrogen in the 1930s. Scientists have always known that it had that action. It is now used mostly in polycarbonate plastic and as a community we have forgotten its origins. We have failed to consider the potential risks as it became more widely used.
In splitting the atom, Rutherford didn't intend that we be able to wipe out the whole world with the push of a button; he didn't intend that his discovery would ultimately change the way that nations engaged with each other, and that for years we would live under the threat of the cold war.
The chemicals that surround us every second of our modern lives are, for the most part, no different. But they have the very real potential to change who we are, how we define ourselve as men and women, and to impact, in drastic and potentially irreversible ways, on our health and our survival and ability to procreate.
Dr Theo Colborn, from the Endocrine Disruptor Exchange and a professor of zoology at the University of Florida, says that we must take action now. In the EHP article ‘Are EDCs Blurring Issues of Gender?’ she said:
“In the animals, it was at the population level that we really began to realize what was going on… If we’re going to wait to see population effects for all of these concerns that we have in the human population, it’s going to be too late.”(37)
She pointed out that “we’re already into the fourth generation of individuals who have been exposed in utero to chemicals that had never been used before the mid-1930s or early 1940s.”
Our bodies have an inherent ability to break down and excrete excess oestrogen that we manufacture in our bodies. However, Dr Colburn says that “many of the man-made compounds resist normal breakdown and accumulate in the body, exposing humans and animals to low-level but long-term exposure. This pattern of chronic hormone exposure is unprecedented in our evolutionary experience.”
In addition, estrogenic chemicals accumulate in our fatty tissue, making it harder for us to rid ourselves of this scourge.
The evidence for the damaging impact of xenoestrogens on the environment and human health is compelling. Although researchers in this field admit that more research is desperately needed, the evidence thus far has been sufficient for some countries to ban the use of some of these substances, particularly in items where their presence may put our children at risk.
We need to lobby our government to take action now. At the very least consumers need to know where these chemicals hide so that they can make informed decisions to avoid them if they so choose – labelling is a must! This is something that the Green Party is pushing for and they have a list of paraben containing cosmetics on their website (www.greens.org.nz/searchdocs/other7561.html.)
And, if ongoing research serves to cement the views of people such as Frederick vom Saal and Theo Colburn, we need to move towards regulation of these substances, and ultimately their replacement with substances that don’t threaten our health and our humanity.
Get Those Xenoestrogens Outta Your Life!
In the meantime, don’t wait around for the government and health agencies to do something – it could be a long wait. If you are concerned by what you’ve discovered about environmental oestrogens, it seems sensible to adopt a precautionary approach, and as far as is practical and as much as you can, remove them from your life.
Because estrogenic chemicals leach out of plastic and into our food, especially when heated, the way in which we store and cook our food is of particular importance. Dr Hofman says that glass is probably the best thing for storing food, and he is moving away from plastic in his own home.
Cosmetics and personal care products that we put onto our skin are also another important source of xenoestrogens. Making some simple changes to the products you use and the way you store your food could make a big difference to the estrogen load in your body.
While the plastics and cosmetics industries appear to be ignoring the evidence, and in fact are publicly denying that there is a problem, the only way most of us can exert any influence is to vote with our wallets. Make changes where you can and buy safer products.
Reduce Your Oestrogen Load By Making Simple Changes
Replace plastic food and beverage containers and kitchen utensils with glass, ceramic or metal where possible.
Don't reheat your food in plastic containers or covered in plastic wrap.
Use greaseproof or waxed paper instead of plastic wrap to cover and wrap your food.
Don’t buy food in plastic or resin lined tins.
Look for phthalate-free plastic toys and containers.
Choose natural, chemical-free personal care items.
Use glass baby bottles. If this is not possible use bottles and baby cups made from polyethylene plastic (1, 2 and 4 recycling symbols) or polypropylene (5) (Non-polycarbonate plastic bottles and cups are usually coloured, not clear.)
Don’t use non-stick and coated cooking utensils, bakeware and pans. Switch to stainless steel and ceramic for the stove and oven.
If you use polycarbonate plastics for food or drink, don’t expose them to heat or harsh detergents. Don’t put them in the microwave or dishwasher.
Avoid polystyrene where possible. Its non-inflated form is used in some disposable plastic cups and bowls and in most opaque plastic cutlery.
Buy food fresh and loose (meat, fruit, vegetables) as much as possible and even if it is placed in plastic for the trip home, transfer it to safe containers as quickly as possible.
Buy natural or organic cosmetics and personal care products, including sunscreen. If this is not affordable or practical, use problem products sparingly.
Switch to organic and natural deodorants such as rock crystal.
* lutenising hormone controls release of eggs from the ovaries.
** abnormally high levels of insulin.
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Copyright © 2006, Sue Claridge