Chemicals and the Hormone-Sensitive Cancers

Kathryn Alexander
www.getalife.net.au

Many observers are concerned that if the current trends in infertility and hormone-sensitive cancers continue to rise due to the increasing levels of toxic chemicals in our environment, then the majority of our children will be affected in some way -- whether from abnormalities, infertility or cancer.  These chemicals disrupt the delicate hormone balance in the developing foetus, but their effects may not become manifest until after a child reaches puberty.

Focusing on the hormone-sensitive cancers (breast, prostate, testicular, ovarian, uterine, cervical), epidemiological and animal studies as well as in vitro studies on cancer tissue cultures have identified that synthetic chemicals, particularly the xeno-oestrogens (environmental oestrogens), stimulate the growth of cancer either directly or indirectly. 

Controlled vs epidemiological studies
Scientifically, this only proves a strong association -- not a cause and effect.  Only a controlled study is able to establish cause, but exposing a group in this way is a huge risk and obviously unethical.  In the meantime, the fallback position remains for manufacturers to set safety margins for these chemicals based on risk assessment extrapolated from animal studies and the highest exposure groups.  These analyses factor in the differences in susceptibility between individuals and species but do not factor in bio-accumulation, i.e., the longer the exposure to a toxin, the greater the risk of it accumulating in your body.  In layperson’s terms, this means there is no risk management.

The other fallback is to continue to collate the results of epidemiological studies or real-life exposure and risks.  The best epidemiological example which links organochlorine insecticides -- DDE (a metabolite of DDT), lindane and alpha benzene hexachloride (aBHC) -- to breast cancer is the Israeli breast cancer anomaly noted during the 1970s to 1980s ¹

In the early 1970s, the incidence of breast cancer was twice the prediction.  The Israeli government looked at levels of three organochlorine insecticides in milk and found between 5 and 100 times the amount found in US milk, and also higher levels in breast milk.  By 1978, the government banned aBHC and, later, lindane from the milking shed.  Breast cancer rates started to decline, but were steadily increasing in other countries. 

During the 1990s, scientists tried to forge a link between organochlorine insecticides and breast cancer.  Studies from the USA, Canada and Finland compared malignant and non-malignant breast tissue samples and found a positive correlation between higher levels of organochlorine compounds in breast fat tissue and cancer.  Levels of DDT and DDE were 50-300% higher in women with hormone-sensitive breast cancer than in those with benign breast disease.  The estimated risk from higher exposure is 2-4 times greater than in those with lower exposure.  Interestingly, other studies found no links at all. 

However, two isomers of DDE (ppDDE and o,pDDE) have recently been identified which appear to have opposing actions, and depending upon which is more prevalent at the scene determines overall activity. ²

The story is similar when we review prostate cancer.  The development of androgen receptors in the prostate gland is governed by oestrogen.  Overexposure to xeno-oestrogens results in an increase in the number of receptors, leading to a permanent sensitisation to testosterone.  This may result in either benign prostatic hypertrophy (enlargement of the prostate), which now affects 80% of males by the age of 70 years, or prostate cancer.

Animal studies have revealed that exposing adult animals to increased oestrogen leads to a 50% increase in androgen receptors and an increased incidence of prostate cancer.  We see similar patterns in human populations.  An increased incidence of prostate cancer was reported in workers at a US manufacturing plant producing the (strongly oestrogenic) herbicide atrazine.  Although this product is already banned in many European countries and will be banned totally by the EU in 2005, the US Environmental Protection Agency decided not to restrict its use.  Currently, 60 million pounds of atrazine is applied annually to US soils. ³

However, the consequences are far more insidious.  Animal studies and correlative evidence in human studies indicate that exposure to xeno-oestrogens in the “correct age window” (i.e., during foetal and neo-natal stages of sex gland development) determines the degree of cell sensitivity to oestrogen in later life.  Xeno-oestrogens are 10 times stronger than human oestrogens, and it is believed that they program hormone-sensitive cells to become more sensitised to both natural hormones and xeno-oestrogens (Colborn, Dumanoski and Myers, Our Stolen Future, ISBN 0-349-10878-1).  It may not be until after puberty that these effects become evident with increasing vulnerability to hormone-sensitive cancers. 

How can we help ourselves?

Although these chemicals are ubiquitous in the food chain, our water supply and household products, we can take steps to limit our exposure.  This is important, as it is the consumer who sets the trends – not governments or multinationals.
• Buy organic produce whenever you can and check the country of origin.  Although DDT use was banned in the USA in 1972, it continues to be produced and exported to the Third World; the export figure in 1991 was 18 million kilograms (Our Stolen Future). 
• Choose ‘safe’ personal care products.  Most creams, cosmetics, perfumes, deodorants and shampoos contain hormone-disrupting chemicals which are absorbed directly through the skin.
• Avoid using chemicals in the home, garden or workplace.
• Avoid plastics and vinyls (including plastic toys for children).
• Adopt a low-fat diet and limit your alcohol intake, as both these factors promote the formation of ‘bad’ oestrogens associated with increased risk.
• Increase your intake of specific phytonutrients – the indoles and the D-glucarates – found in cruciferous vegetables (e.g., cabbage, cauliflower, Brussels sprouts, kale and turnips).  These nutrients not only assist in carcinogen and oestrogen elimination but may slow down or arrest tumour growth. 

Impressive research with animal models has proved that the indole family (indole 3 carbinol or I3C) is anti-androgenic and decreases the proliferation of human prostate cancer cells in vitro.  These results are comparable to the standard prostate cancer therapy, Cosadex. 
Similarly, both the incidence and number of tumours fell in breast cancer–prone rats supplemented with I3C.  I3C is not only anti-androgenic but also alters the ratio between ‘good’ and ‘bad’ oestrogens and their metabolites.  Elevated levels of ‘bad’ oestrogens correlate with increased incidence of cancer.  Indoles push oestrogen down a ‘good’ pathway where the rise in ‘good’ oestrogens blocks the strong growth signals of the ‘bad’ oestrogens.  DDE and other related chemicals push oestrogens down the ‘bad’ pathway. ⁴

Similarly, research with calcium D-glucarate (CDG) (found in grapefruit, apples, oranges and the cruciferous vegetables) shows that this supplement lowers serum oestrogen levels, increases the elimination of carcinogens and oestrogens in the stool, and decreases the growth of tumours already present.  It has been tested in animal models and human tumour cell cultures.  In one controlled animal experiment, the group supplemented with CDG became resistant to the induction of breast cancer with carcinogens, while the control group developed tumours. ⁵

Facts on phytonutrients
This article wouldn’t be complete without a final word about another group of phytonutrients which includes the isoflavones found in the pea family, such as soybeans and red clover, and the lignans found in linseed. 

Lignans can inhibit oestrogen-stimulated breast cancer cell growth in vitro, while the isoflavones are weak oestrogens which can occupy oestrogen receptor sites and inhibit the strong effects of other oestrogens including the xeno-oestrogens.  However, although these isoflavones can inhibit the proliferative effects of xeno-oestrogens on breast cancer cells, they can also induce proliferation in the absence of natural oestrogen (Mills and Bone, Principles and Practice of Phytotherapy, ISBN 0-443-06016-9). 
So while these products may be protective against cancer before the event, you would need to seek the advice of a qualified professional if you already have cancer.

1.      http://www.pesticide.org/BCancerReport.pdf

2.      http://www.cbcrp.org/research/PageGrant.asp?grant_id=1811

3.      http://www.nrdc.org/health/pesticides/natrazine.asp

4.      http://psa-rising.com/eatingwell/broccoli_DIM_05_2003.htm  http://www.digitalnaturopath.com/treat/T271617.html

5.      http://www.md-phc.com/nutrition/calcium_d.htm