By Dr. Mercola
Recent research reveals American girls are hitting puberty earlier than ever before. The median age for breast development is now around 9, with rare cases of extreme precocious puberty occurring in girls as young as 4.
Precocious puberty is triggered by premature release of hormones, which results in sexual maturation, sometimes years before the natural norm. Research into the phenomenon reveals that environmental exposure to endocrine-disrupting chemicals plays a major if not decisive role.
Interestingly, recent research1 also claims that high sugar consumption — specifically soda — can affect young girls' rate of maturation. According to associate professor Karin Michels, who studies links between environmental exposures, genetics and disease:
"Our study adds to increasing concern about the widespread consumption of sugar-sweetened drinks among children and adolescents.
The main concern is about childhood obesity, but our study suggests that age of first menstruation (menarche) occurred earlier, independently of body mass index, among girls with the highest consumption of drinks sweetened with added sugar."
Early onset of puberty has ramifications that go far beyond mere physical changes. Emotions, behavior, mental and physical health can all be detrimentally affected.
While some parents are resorting to drug treatment to keep puberty at bay in their prematurely developing daughters, a more proactive approach would be to limit exposure to endocrine-disrupting chemicals, starting as early before birth as possible, and to address your child's diet — specifically restricting all forms of sugar as much as possible.
The Ramifications of Early Puberty
Hormones, emotions and behavior tend to go hand in hand, which can lead to distress both in the child and her parents when puberty comes years ahead of schedule. As noted in a recent Newsweek2 article:
"The mother of one 8-year-old wrote that her daughter 'is a very sexual being. Although she does not by definition understand what 'sexiness' means, she exhibits a very particular awareness of her body and wants other people to notice her...'
[N]o matter how physically developed a girl is, her psychosocial maturation remains anchored to her chronological age. 'These young girls get, let's use the term 'hit on,' by older boys and men and how can they be prepared to deal with it?
Obviously, grown women have a hard [enough] time dealing with unwanted sexual attention,' observes [Dr. Marcia] Herman-Giddens [professor of public health at the University of North Carolina].
The brain is highly plastic, and stressful experiences like these take their toll. Early-maturing girls are more likely to smoke cigarettes, they are at high risk for substance use, and they have higher rates of eating disorders."
Precocious puberty is also associated with an increased lifetime risk of estrogen-sensitive breast cancer. For example, one 2013 study3 found that early puberty was associated with a 30 percent higher risk for breast cancer compared to entering puberty at a later age.
Also, for each year that onset of menstruation was delayed, the risk for premenopausal breast cancer was reduced by 9 percent. The risk for postmenopausal breast cancer was reduced by 4 percent.
Early Puberty Associated With Elevated Chemical Exposures
The definition of puberty in girls includes breast development, growth of pubic hair and onset of menstruation. The average age of puberty for girls in the U.S. was 16 to 17 at the turn of the 20th century. Today the mean age at which girls get their first period is 12.4
According to data from the most recent National Health and Nutrition Examination Survey,5 early onset of menstruation appears to be associated with elevated levels of certain chemicals, such as 2, 5-dichlorophenol (2, 5-DCP).
2, 5-DCP is a metabolite of 1,4-dichlorobenzene (paradichlorobenzene), a chemical used in moth balls, room deodorizers, toilet bowl cleaners and other household cleaning products. According to the Centers for Disease Control and Prevention6 (CDC):
"Paradichlorobenzene has been detected in ambient air in households, bathrooms and new buildings, and in exhaled breath samples of persons living in households where room deodorizers and moth crystals were used.
2,5-Dichlorophenol can also be formed in waste water treatment, wood pulp processing, and during the incineration of wood, coal and municipal waste.
12 Worst Endocrine Disruptors
As explained in an informative pamphlet7 on pesticides and endocrine disruption by Beyond Pesticides, endocrine-disrupting chemicals cause harm by:
- Mimicking the action of a naturally-produced hormone, such as estrogen or testosterone
- Blocking hormone receptors in your cells, thereby preventing the action of normal hormones
- Affecting the synthesis, transport, metabolism and excretion of hormones, thus altering the concentrations of natural hormones in your body
Some of the biggest offenders are plastic compounds like phthalates and bisphenols (BPA and BPS) — if nothing else for the fact that they're so ubiquitous.
Plastics are used in every imaginable household product, so you really have to make some decisive lifestyle changes to limit your exposure to these chemicals.
Even then you're unlikely to avoid them entirely. Plastics continue spreading their chemicals into the environment even after they've been used and thrown away. Microscopic plastic particles now fill the water column in our oceans, where they get re-circulated back into our food supply.8
As noted in the featured article,9 your body cannot metabolize phthalates, and indirectly, these chemicals can have an adverse effect on both weight and timing of puberty. Disturbingly, recent research also suggests that prenatal phthalate exposure may lead to reduced IQ in children.
Bisphenol-A and bisphenol-S mimic the hormone estrogen, and as noted in a 2011 study,10 BPA is similar in potency to estradiol, and may influence a number of different endocrine-related pathways.
Moreover, in animal research, adverse effects of BPA have been noted at levels below current acceptable daily intake (RDI) levels.
Besides phthalates and bisphenols, other potent endocrine disruptors include the following.11 I've written about many of these in prior articles, so for more information about any particular one, please follow the links provided.
Endocrine Disruption Can Affect Reproductive Health Throughout Life
On the flip side of early puberty you have early menopause. Many of the same chemicals that cause precocious puberty are also associated with early menopause, which can have an adverse effect on ovarian function.
One recent study12 discovered that women with high levels of 15 different chemicals, including PCBs, pesticides and phthalates, typically entered menopause two to four years earlier than those with lower levels.
A woman's reproductive health can also be affected at any point during her childbearing years, via a number of different mechanisms that can be traced back to chemical overexposures.
For example, the thyroid gland is part of your endocrine system, and is therefore also vulnerable to endocrine-disrupting chemicals. Interestingly, recent research suggests that hyperthyroidism, a condition in which your thyroid is overactive, may contribute to fertility and pregnancy problems in women. The authors suggest that women struggling with infertility and/or repeated miscarriages should get tested for thyroid disease.
The study,13,14 published in The Obstetrician & Gynecologist, found that 2.3 percent of women with fertility problems had an overactive thyroid (hyperthyroidism), compared to 1.5 percent of those in the general population. According to co-author Amanda Jeffreys:
"Abnormalities in thyroid function can have an adverse effect on reproductive health and result in reduced rates of conception, increased miscarriage risk and adverse pregnancy and neonatal outcomes."
In terms of treatment, conventional options for hyperthyroidism—such as surgery or the use of radioactive iodine — tend to produce poor results. While I don't generally advise taking iodine supplements, if testing does confirm that you have hyperthyroidism, a more effective treatment option for you and your doctor is discussed by Dr. Jonathan Wright in the following video.
According to Dr. Wright, normal thyroid levels can often be achieved in less than two weeks with the following protocol:
- Patient starts out on five drops of Lugol's iodine, three times per day
- After four or five days, patient starts receiving 300 mg of lithium carbonate, one to three times per day
If you do decide to follow this protocol, it's important that your physician know about it, as serious effects can occur if you take too much of either treatment, particularly lithium carbonate.
WHO Says Banning Endocrine-Disrupting Chemicals May Be Needed to Protect Human Health
In 2013, the World Health Organization (WHO) released a report co-produced with the United Nations Environment Program (UNEP), titled "State of the Science of Endocrine Disrupting Chemicals."15 The report suggests that outright banning all endocrine disrupting chemicals (EDCs) may actually be needed to protect the health of future generations. According to the report:
"The diverse systems affected by endocrine-disrupting chemicals likely include all hormonal systems and range from those controlling development and function of reproductive organs to the tissues and organs regulating metabolism and satiety. Effects on these systems can lead to obesity, infertility or reduced fertility, learning and memory difficulties, adult-onset diabetes or cardiovascular disease, as well as a variety of other diseases."
Tips to Help You Avoid Toxic Chemicals
Although it's virtually impossible to steer clear of all endocrine-disrupting chemicals, you can certainly minimize your family's exposure by keeping some key principles in mind.
- Eat mostly fresh, raw whole foods. Processed and packaged foods are a common source of BPA and phthalates — particularly cans, but also foods packaged in plastic wrap.
- Buy products that come in glass bottles rather than plastic or cans.
- Store your food and beverages in glass, rather than plastic, and avoid using plastic wrap. Use glass containers if heating food in your microwave, as heat tends to increase the release of chemicals from plastic. Be aware that even "BPA-free" plastics typically leach other endocrine-disrupting chemicals that are just as bad as BPA.
- Use glass baby bottles for your infants.
- Be careful with cash register receipts. If you use a store regularly, encourage the management to switch to BPA-free receipts. I shop at Publix for my food and when I called them about the receipts it turns out they already switched. Nevertheless it is wise to limit your contact with all these receipts.
- Look for products that are made by companies that are Earth-friendly, animal-friendly, sustainable, certified organic and GMO-free. This applies to everything from food and personal care products to building materials, carpeting, paint, baby items, furniture, mattresses, and more. When redoing your home, look for "green," toxin-free alternatives in lieu of regular paint and vinyl floor coverings, the latter of which is another source of phthalates.
- Choose toys made from natural materials to avoid plastic chemicals like phthalates and BPA/BPS, particularly for items your child may be prone to suck or chew on.
- Breastfeed your baby exclusively if possible, for at least the first year (to avoid phthalates exposure from infant formula packaging and plastic bottles/nipples).
- Use natural cleaning products, or make your own.
- Switch over to organic toiletries, including shampoo, toothpaste, antiperspirants and cosmetics. EWG's Skin Deep database16 can help you find personal care products that are free of phthalates and other potentially dangerous chemicals.
- Replace your vinyl shower curtain with a fabric one.
- Replace feminine hygiene products (tampons and sanitary pads) with safer alternatives. While most ingredients in feminine hygiene products are undisclosed, tests suggest they may contain dioxins and petrochemical additives.
- Look for fragrance-free products: phthalates are often used to help the product hold its fragrance longer. Artificial fragrance can also contain hundreds — even thousands — of potentially toxic chemicals. Avoid fabric softeners, dryer sheets, air fresheners and scented candles for the same reason.
- Check your home's tap water for contaminants and filter the water if necessary. You may also want to use an alternative to PVC pipes for your water supply.
- Teach your children not to drink water from the garden hose, as many are made with phthalate-containing plastics. They are typically more expensive but usually higher quality hoses are well worth the investment.
- Avoid using pesticides and herbicides around your home.
- Avoid all products containing triclosan, which is yet another endocrine-disruptor. The chemical structure of triclosan is similar to thyroid hormones and polychlorinated biphenyls (PCBs), allowing it to attach to thyroid hormone receptors.