Reaching puberty is a rite of passage that we've all been
through, but children nowadays are reaching it earlier than
ever before -- a trend that has both health experts and
parents alarmed.
Precocious puberty, which is the appearance of secondary
sex characteristics like pubic hair or breast growth before
age 8, or the onset of menarche before age 9, impacts at
least 1 in 5,000 U.S. children, and the rate is on the rise.i
Even in the last three decades, children (particularly
girls) are maturing at younger and younger ages (precocious
puberty is 10 times more common in girls than in boys).
Puberty, Once the Norm at Age 15, Now Occurring in 7-, 8-
and 9-Year-Olds
In the 19th century the onset of menstruation occurred
around the age of 15.
Now the average age of the first period, or menarche, is
around 12.
The time during and before puberty is one of rapid
development and change, which is why even months matter when
it comes to first menstruation.
Before menstruation, girls will show beginning signs of
development, such as breast "budding" and growth of pubic
hair.
These signs are now becoming unsettlingly common among
7-, 8- and 9-year-old girls, to the extent that many health
care providers, rather than labeling these children with a
diagnosis that something is wrong, have simply changed the
definition of what's normal … but is it really "normal" for
girls to mature at such a young age?
There are more questions than answers in the case of
precocious puberty, but what is certain is that girls are
developing earlier than they have even 10, 20 or 30 years
ago.
One study in the journal Pediatrics revealed
that by age 7, 10 percent of white girls, 23 percent of
black girls, 15 percent of Hispanic girls and 2 percent of
Asian girls had started developing breasts, with researchers
noting:ii
"The proportion of girls who had breast
development at ages 7 and 8 years, particularly among
white girls, is greater than that reported from studies
of girls who were born 10 to 30 years earlier."
Early puberty can set the stage for emotional and
behavioral problems, and is linked to lower self-esteem,
depression, eating disorders, alcohol use, earlier loss of
virginity, more sexual partners and increased risk of
sexually transmitted diseases. There is also evidence that
suggests these girls are at increased risk of diabetes,
heart disease and other cardiovascular diseases, as well as
cancer, later in life.
Environmental Chemicals a Likely Factor
Scientists have brought forth a number of potential
explanations for the rising rates of early puberty, but one
that deserves special attention is environmental chemicals,
and particularly estrogen-mimicking, "gender-bending"
chemicals that easily leach out of the products that contain
them, contaminating everything they touch, including food
and beverages.
As the featured New York Times article reported:
" … animal studies show that the exposure to some
environmental chemicals can cause bodies to mature
early. Of particular concern are endocrine-disrupters,
like "xeno-estrogens" or estrogen mimics. These
compounds behave like steroid hormones and can alter
puberty timing. For obvious ethical reasons, scientists
cannot perform controlled studies proving the direct
impact of these chemicals on children, so researchers
instead look for so-called "natural experiments," one of
which occurred in 1973 in Michigan, when cattle were
accidentally fed grain contaminated with an
estrogen-mimicking chemical, the flame retardant PBB.
The daughters born to the pregnant women who ate
the PBB-laced meat and drank the PBB-laced milk started
menstruating significantly earlier than their peers."
This is an extreme case, but the truth is we are all part
of a "secret experiment" of sorts, because
hormone-disrupting chemicals are all around us. Bisphenol A
(BPA), an industrial petrochemical that acts as a synthetic
estrogen, is found in our plastics and our tin can linings,
in dental sealants and on cash-register receipts. Laboratory
tests commissioned by the Environmental Working Group (EWG)
detected BPA in the umbilical cord blood of
90 percent of newborn infants tested -- along with more
than 230 other chemicals. As written in the New York
Times:
"One concern, among parents and researchers, is
the effect of simultaneous exposures to many
estrogen-mimics, including the compound BPA, which is
ubiquitous."
No one knows what happens when a developing fetus or
young child is exposed to hundreds of chemicals, many of
which mimic your body's natural hormones and can trigger
major changes in your body even as an adult, let along
during the most rapid and vulnerable periods of development
(in utero and as a young child).
BPA is, unfortunately, but one example. Others include
phthalates, a group of industrial chemicals used to make
plastics like polyvinyl chloride (PVC) more flexible and
resilient. They're also one of the most pervasive of the
endocrine disrupters, found in everything from processed
food packaging and shower curtains to detergents, toys and
beauty products like nail polish, hair spray, shampoo,
deodorants, and fragrances.
Other environmental chemicals like PCBs and DDE (a
breakdown product of the pesticide DDT) may also be
associated with early sexual development in girls. Both DDE
and PCBs are known to mimic, or interfere with, sex
hormones.
Perfluorooctanoic acid (PFOA), found in non-stick
cookware, also falls into this dangerous category, as does
fluoride, which is added to the majority of public water
supplies in the United States. Research showed that
animals treated with fluoride had lower levels of
circulating melatonin, as reflected by reduced levels of
melatonin metabolites in the animals' urine. This reduced
level of circulating melatonin was accompanied -- as might
be expected -- by an earlier onset of puberty in the
fluoride-treated female animals.
These Chemicals Also Increase Your Risk of Cancer and Heart
Disease
If a chemical is capable of influencing the rate of your
reproductive development, it stands to reason that it would
be capable of influencing other hormone-sensitive growth
processes as well, and this is indeed the case.
For instance, new research has detected the presence of
paraben esters in 99 percent of breast cancer tissues
sampled.iii
Parabens are chemicals with estrogen-like
properties, and estrogen is one of the hormones involved in
not only puberty but also the development of breast cancer.
They are widely used in household products such as:
Deodorants and antiperspirants
Shampoos and conditioners
Shaving gel
Toothpaste
Lotions and sunscreens
Make-up / cosmetics
Pharmaceutical drugs
Food additives
Recent research has also confirmed the existence of a
previously unknown class of cancer-causing
estrogen-mimicking compounds: metals. Yes, a broad range of
metals have been shown to act as "metalloestrogens" with the
potential to add to the estrogenic burden of the human body,
thereby increasing the risk of breast cancer and also
possibly early puberty. The following metals, which are
added to thousands of consumer products, including vaccines,
have been identified as being capable of binding to cellular
estrogen receptors and then mimicking the actions of
physiological estrogens:iv
Aluminum
Antimony
Arsenite
Barium
Cadmium
Chromium
Cobalt
Copper
Lead
Mercury
Nickel
Selenite
Tin
Vanadate
Data from a long-running British health survey,
meanwhile, has shown that if you have high levels of the
chemical BPA in your urine, you may be at an
increased risk of heart disease. Some of the greatest
concern surrounds early-life, in utero exposure to BPA,
which can lead to chromosomal errors in your developing
fetus, causing spontaneous miscarriages and genetic damage.
But evidence is also very strong showing these chemicals are
influencing adults and children, too, and leading to
decreased sperm quality, early puberty, stimulation of
mammary gland development, disrupted reproductive cycles and
ovarian dysfunction, obesity, cancer and heart disease,
among numerous other health problems.
Avoiding Hormone-Disrupting Substances is Crucial for
Children and Adults Alike
While young girls may show obvious signs of exposure to
hormone-disrupting substances via early puberty, other
signals are more insidious and may not show up until a
disease is already present. Here are 11 measures you can
implement right away to help protect yourself and your
children from common toxic substances that could cause
precocious puberty and other long-term health problems:
As much as possible, buy and eat organic produce and
free-range, organic meats to reduce your exposure to
added hormones, pesticides and fertilizers. Also avoid
milk and other dairy products that contain the
genetically engineered recombinant bovine growth hormone
(rBGH or rBST)
Eat mostly raw, fresh foods. Processed, prepackaged
foods (of all kinds) are a major source of soy and
chemicals such as BPA and phthalates.
Store your food and beverages in glass rather than
plastic, and avoid using plastic wrap and canned foods
(which are often lined with BPA-containing liners).
Use glass baby bottles and BPA-free sippy cups for
your little ones.
Make sure your baby's toys are BPA-free, such as
pacifiers, teething rings and anything your child may be
prone to suck on.
Only use natural cleaning products in your home to
avoid phthalates.
Switch over to natural brands of toiletries such as
shampoo, toothpaste, antiperspirants and cosmetics. The
Environmental Working Group has a great safety guide to
help you find personal care products that are free of
phthalates, parabens and other potentially dangerous
chemicals.
Avoid using artificial air fresheners, dryer sheets,
fabric softeners or other synthetic fragrances, many of
which can also disrupt your hormone balance.
Replace your non-stick pots and pans with ceramic or
glass cookware.
When redoing your home, look for "green," toxin-free
alternatives in lieu of regular paint and vinyl floor
coverings.
Replace your vinyl shower curtain with one made of
fabric.
Avoid non-fermented soy, especially if you're
pregnant and in infant formula.
Theo Colburn's book Our Stolen Future is a great
source for further investigation as it identifies the
numerous ways in which environmental pollutants are
disrupting human reproductive patterns. I believe it is one
of the best resources on this topic and highly recommend it.
Vitamin D Also Linked to Early Puberty
It has been suggested that girls who live closer to the
equator start puberty at a later age than girls who live in
Northern regions. Since this indicates a potential
connection with sun exposure, researchers decided to
investigate whether vitamin D was, in fact, related.
Upon measuring vitamin D levels in 242 girls aged 5-12,
researchers from the University of Michigan School of Public
Health found that those who were deficient were twice as
likely to start menstruation during the study period as
those with higher levels.v
Specifically, among the vitamin-D-deficient girls, 57
percent started their period during the study, compared to
23 percent with adequate vitamin D. However, researchers
defined adequate vitamin D as ≥ 30 ng/mL, which is actually
still a deficiency state! For optimal health, vitamin D
levels should be a minimum of 50 ng/mL, which means the
number of vitamin-D-deficient girls with early puberty was
probably much higher than the study reported.
The earlier you enter puberty, the longer you're exposed
to elevated levels of the female hormone estrogen, which is
a risk factor for certain cancers such as breast cancer.
This has been the primary "link" between early puberty and
cancer that has been explored, but it's important to
understand that vitamin D deficiency is also a major risk
factor for cancer, heart disease and many other diseases. So
it could be that some of the increased risks that come from
early puberty are linked to low vitamin D levels.
What You Should Know About Obesity, Stress and Exercise
Obesity (which exposes girls to more estrogen because
estrogen is both stored and produced in fat tissue) is
another likely factor in early puberty. The New York
Times reported:
"As Robert Lustig, a professor of clinical
pediatrics at the University of California, San
Francisco's Benioff Children's Hospital, explains,
fatter girls have higher levels of the hormone leptin,
which can lead to early puberty, which leads to higher
estrogen levels, which leads to greater insulin
resistance, causing girls to have yet more fat tissue,
more leptin and more estrogen, the cycle feeding on
itself, until their bodies physically mature."
As for stress, this, too, has been linked to early
puberty, with girls whose parents divorced when they were
between 3- and 8-years-old significantly more likely to
experience precocious puberty.
"Evolutionary psychology offers a theory," the New
York Times reports. "A stressful childhood inclines a
body toward early reproduction; if life is hard, best to
mature young. But such theories are tough to prove."
Interestingly, in addition to avoiding environmental
chemicals, obesity and stress, and optimizing your vitamin
D, regular exercise appears to be one of the best known ways
to help prevent early puberty.