WHAT ARE HORMONE DISRUPTORS?
Alien
hormone messengers
– in the form of
man-made chemicals
– have entered
our environment in overwhelming amounts over the last fifty years. These
synthetic chemicals enter our bodies through the food we eat, the water
we drink and bathe in, and the air we breathe. Some
of these chemicals have the ability to masquerade as hormones.
They ride freely through the blood stream, not subject to the rules and
regulations that guide natural hormones, and bind with hormone receptors.
They deliver a message to central headquarters. Responses take place,
even if the orders are inappropriate. Hormone disruptors may:
-
Mimic the natural hormones in our bodies, such as estrogens.
-
Antagonize (block) our natural hormones, such as androgens (male hormones), thyroid, and progesterone.
-
Alter the way in which natural hormones are produced or eliminated.
-
Modify the number of hormone receptors we have and thus the amount of hormonal signaling in our bodies.
-
Stimulate the release of other hormones or other natural substances that affect the balance of our hormones in our bodies.
Are they different from natural hormones?
If
hormone disruptors mimic our own hormones, aren't these chemicals basically
the same as our natural hormones?
No, they're not.
Natural hormones are short-lived, staying in our bodies only for the amount of time necessary to do their jobs. They don't accumulate in the tissues and are easily broken down and eliminated by our bodies.
The
same seems to be true for phytoestrogens. These plant compounds
are either flushed out or changed and absorbed into the body in a (usually)
beneficial way. Synthetic estrogens, like those in birth control
pills, fertility drugs, or hormone replacement therapy, are pharmaceutical
drugs that remain in the body longer than natural estrogens. However,
they are not nearly as long-lived as pesticides and other environmental
compounds that can act like hormones.
On
the other hand, many hormone-disrupting chemicals are not easily
broken down by the body. They remain intact inside living organisms and
can accumulate within our tissues. Most are lipophilic, meaning
they are attracted to fat and don't dissolve easily in water. This means
that hormone disruptors aren't easy to flush out of the body; instead,
they take up residence in our fat cells and may stay there for many years,
even decades. In a woman's body, fatty tissue is concentrated in the breast
and ovaries, and in the placenta during fetal development, but is also
found in other organs, including the brain, as well as throughout the
body for padding, insulation, and as caloric reserves.
Estrogen
is so potent in small amounts that, according to Natalie Angiers, Pulitzer
prize-winning author of Woman
– An
Intimate Geography, if we drained the blood of 250,000 premenopausal
women, all in their high estrogen years, we'd get ONE teaspoon of the
active estrogen, estradiol.
Hormone disruptors may similarly have very powerful effects, even in very low doses.
No, they're not.
Natural hormones are short-lived, staying in our bodies only for the amount of time necessary to do their jobs. They don't accumulate in the tissues and are easily broken down and eliminated by our bodies.
The
same seems to be true for phytoestrogens. These plant compounds
are either flushed out or changed and absorbed into the body in a (usually)
beneficial way. Synthetic estrogens, like those in birth control
pills, fertility drugs, or hormone replacement therapy, are pharmaceutical
drugs that remain in the body longer than natural estrogens. However,
they are not nearly as long-lived as pesticides and other environmental
compounds that can act like hormones. On
the other hand, many hormone-disrupting chemicals are not easily
broken down by the body. They remain intact inside living organisms and
can accumulate within our tissues. Most are lipophilic, meaning
they are attracted to fat and don't dissolve easily in water. This means
that hormone disruptors aren't easy to flush out of the body; instead,
they take up residence in our fat cells and may stay there for many years,
even decades. In a woman's body, fatty tissue is concentrated in the breast
and ovaries, and in the placenta during fetal development, but is also
found in other organs, including the brain, as well as throughout the
body for padding, insulation, and as caloric reserves. Estrogen
is so potent in small amounts that, according to Natalie Angiers, Pulitzer
prize-winning author of Woman
– An
Intimate Geography, if we drained the blood of 250,000 premenopausal
women, all in their high estrogen years, we'd get ONE teaspoon of the
active estrogen, estradiol.Hormone disruptors may similarly have very powerful effects, even in very low doses.
The
hypothesis is that multiple chemicals in the environment trick the
body, trick this developing embryo into thinking that it's getting
a signal, a normal signal.
|
Where are these hormone disruptors coming from?
The
man-made chemicals that can disturb the endocrine system within our bodies
are the by-products or building blocks of fuels, pesticides, detergents,
and plastics –
the regular stuff of life as we enter the new millennium.
Normally we don't think at all about the synthetic chemicals that have given
us our modern lifestyle. Today's technology makes our lives easier, fuller,
and more fascinating. How different would our lives be without a computer,
TV, telephone, microwave, automobile, or disposable diapers and fast food?
Since World War II, approximately 87,000 new chemicals have been synthesized in America alone.
New
ones are always being invented, at the rate of at least 2,000 a year. Chemicals
have been responsible for some great strides forward, such as giving us
the ability to prevent or fight the diseases that used to wipe out large
segments of the population, allowing us to live longer. There is no way
we will turn back the clock, nor would we want to turn away from the progress
that has given us so much. However, we cannot be blind to the consequences
of this progress.
| Chemicals, by themselves, are not good or bad. Generally, they are cheap to produce and highly effective. It wasn't until they had been used for decades that some of their health and environmental effects surfaced. Endocrine disruptors are part of a complex set of interlocking problems in our modern life. |
It's a spaceship Earth problem.
We
all share a common ecosystem and must all accept the responsibility for
our effect upon it. Our planet is a relatively closed system
– energy is coming
in from the sun and we're losing heat, but everything we make and do stays
with us. We can never go back to living in isolation, apart from those who
live in other areas of the world. In an intimate dance, we affect the environment
with our technological culture, and, in turn, endocrine-disrupting chemicals
have the potential to affect us all. We could call it the shadow side
of technology.Dr. Theo Colborn is the Director and Senior Scientist of the Wildlife and Contaminants Program at the World WildLife Fund, and a co-author of Our Stolen Future. She was the first person, with visionary prowess, to synthesize the vast literature on the problems wildlife were experiencing and to recognize that many of the effects that were being observed were related to disruption of the endocrine system. Colborn has said the topic of global exposure to hormone mimics is so huge that it is a moral issue even more than a scientific one.