By Dr. Mercola
American children are hitting puberty earlier than ever before, and the health ramifications of this go far beyond the obvious emotional challenges it may produce. A recent longitudinal1 study, published in the November 2013 issue of Pediatrics,2 examined the age at onset of breast development, and the impact of BMI and ethnicity on the precocious puberty trend.
While breast development varied by race, BMI, and location, the study found that girls across the spectrum are now entering puberty3 far earlier than previously documented. The median age at onset of breast development was:4
- 8.8 for African American girls
- 9.3 for Hispanics
- 9.7 for white non-Hispanics and Asians
German research5 published in 2012 showed that the onset of puberty for girls had dropped by four years since 1920, and six years over the last century. However, as discussed in the video above, there are even cases of girls now exhibiting the physical signs of puberty as early as age four!
According to another study in the journal Pediatrics,6 boys are also beginning sexual development anywhere from six months to two years earlier than the medically accepted standard. Clearly, something unusual is taking place, altering human development as we know it.
The Link Between Obesity and Early Puberty
Upward trends in childhood obesity seem to be playing a major role here. Overweight and obese girls in the featured study7 developed breasts about a year earlier than normal-weight girls. Childhood obesity rates have skyrocketed over the past few decades. As reported by Huffington Post8 late last year:
- Childhood obesity has nearly tripled since 1980
- 17 percent of children and adolescents are now obese
- Obesity among kids ages two to five has doubled over the past 30 years, and one in five kids is now overweight by age six
- More than half of obese children were overweight by their second birthday
Toxic Diet, Obesity, Precocious Puberty—A Harmful Mix for Long-Term Health
One of the driving factors behind rising obesity rates among our youth, as well as precocious puberty, is poor diet. The food industry spends more than $1.8 billion marketing to kids each year9 — and what they’re selling is primarily processed food and junk food, filled with processed fructose and chemicals known to affect sex hormones.
In turn, high sugar intake, hormone-mimicking chemicals, obesity, and precocious puberty ALL contribute to cancer, placing the current generation of children at a much higher risk of devastating health problems than their parents...
For starters, obesity exposes girls to higher estrogen levels because estrogen is both produced and stored in fat tissue. Girls carrying excess body fat therefore have more estrogen and leptin, which can lead to insulin resistance and the development of more fat tissue.
This produces even more estrogen—it’s a vicious cycle that can result in premature puberty, and raises the risk of estrogen-sensitive cancers such as breast cancer later on in life. Childhood obesity also raises your child’s risk for the following serious health concerns, which frequently persists into adulthood:10
- Impaired insulin resistance and type 2 diabetes
- Cardiovascular disease, asthma, and other respiratory problems
- Fatty liver disease
- Joint and musculoskeletal problems, and lower extremity fractures11
- Gallstones and gastroesophageal reflux (GERD)
Interestingly, research from the University of Michigan School of Public Health12 also suggests vitamin D deficiency may be a contributing factor to early puberty. Those who were deficient were twice as likely to start menstruation during the study period as those with higher levels, in this 2011 study. Specifically, among the vitamin D-deficient girls, 57 percent started their period during the study, compared to only 23 percent of girls who had a vitamin D level at or above 30 ng/ml.
Recent research also suggests that obese people have HIGHER vitamin D requirements than fitter individuals, so making sure your child maintains an optimal level of vitamin D is likely critical for more reasons than one. Sadly, parents are constantly bombarded with warnings about the hazards of sun exposure. So not only are children overexposed to hormone-disrupting chemicals and excess sugar, courtesy of processed foods, they’re also underexposed to nutrients such as vitamin D, which your body naturally creates in response to UV light striking your skin.
Obesity and Toxic Environmental Chemicals: Two Sides of Same Coin?
There is mounting scientific evidence that environmental contaminants have hormone-mimicking properties that may play a role in premature sexual development. However, it is difficult to measure these effects, despite their strong theoretical basis. In terms of research, it’s much easier to correlate a child’s age of onset of puberty with her body mass index (BMI) than with her level of exposure to plastics or pesticides.
However, the obesity and contamination factors are likely two sides of the same coin, having been linked in multiple scientific studies. The same chemicals that contribute to precocious puberty are in fact also significant players in obesity, such as phthalates,13, 14, 15, 16 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. Even low levels of toxic chemicals like phthalates have been shown to cause metabolic changes in mice.
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 still added to the majority of public water supplies in the United States. Research has shown that animals treated with fluoride have 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 by an earlier onset of puberty in the fluoride-treated female animals.
Perhaps the relationship between endocrine-disrupting chemicals and precocious puberty will be clearer in the near future, as the researchers in this latest longitudinal study plan to tackle the chemical exposure issue next.17 In the meantime, for a list of the top 10 chemicals that can potentially cause early puberty in your child, please refer to my previous article on this topic.
Hormone-Mimicking Chemicals Also Raise 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, research18 published in 2012 noted the presence of paraben esters in 99 percent of breast cancer tissues sampled. Parabens are chemicals with estrogen-like properties, and estrogen is one of the hormones involved in both puberty and breast cancer. Parabens are pervasive in Western societies, as they are widely used in household staples such as:
Deodorants and antiperspirants Shampoos and conditioners Shaving gel Toothpaste Lotions and sunscreens Make-up / cosmetics Pharmaceutical drugs Food additives
Inactivity Reaching New Heights as Well
The average obese woman gets a mere one hour of vigorous exercise per year, and obese men break a sweat just over 3.5 hours annually.19 This shocking piece of data was revealed in a recent study published in Mayo Clinic Proceedings.20 To reach their conclusions, the researchers examined results from a 2005-2006 government survey of 2,600 American adults between the ages of 20 to 74.
Weight, diet, and sleep patterns were tracked in the survey. To determine the level of physical exertion, accelerometer devices were used. “Vigorous exercise” was defined as fat-burning activities such as jogging or jumping rope. According to Edward Archer,21 a research fellow with the Nutrition Obesity Research Center at the University of Alabama at Birmingham:
"They're living their lives from one chair to another. We didn't realize we were that sedentary. There are some people who are vigorously active, but it's offset by the huge number of individuals who are inactive... People don't understand that [you] don't have to go to the gym and lift weights and run marathons to have dramatic impacts on your body. Standing rather than sitting, walking rather than taking your car, they have huge impacts on your health over time."
This finding relates to adults, but children are increasingly inactive as well. Many schools have ditched physical education classes, and many children spend most of their free time glued to one electronic device or another. This can clearly set the stage for a life of extreme inactivity later on. After all, the heavier a person gets, the less they’re inclined to move. So please, let this frightening statistic be a warning bell for you. Encourage your child to lead an active lifestyle, along with cleaning up their diet.
Tips for Preventing Obesity and Reducing Exposure to Hormone-Disrupting Chemicals
As you can see, precocious puberty is much more than an incidental trend. You can minimize problems by taking steps to optimize your child’s physical and emotional health, beginning the day she is born—or failing that, beginning today! In addition to avoiding excess sugar, junk food, and toxic products, make sure your children get adequate exercise, which is crucial in preventing them from becoming overweight or obese. Physical activity is also important for their mental health.
You can cut back on your family's exposure to dangerous chemicals by implementing the following guidelines. Pregnant women and women who may become pregnant should pay particular attention to reducing their exposure as much as possible, in order to protect the health of their unborn babies.
- Eat fresh, whole, non-GMO, preferably organic produce and free-range, grass-fed and finished meats to reduce your and your child’s 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). Processed, prepackaged foods are a major source of soy and chemicals such as BPA and phthalates.
- Rather than eating conventional or farm-raised fish, which are often heavily contaminated with PCBs and mercury (which also has hormone-disrupting effects), supplement with a high-quality purified krill oil, or eat fish that is wild-caught and lab-tested for purity. Wild-caught Alaskan salmon is about the only fish I eat for these reasons.
- Filter your tap water—both for drinking and bathing. In fact, if you can only afford to do one, filtering your bathing water may be more important, as your skin absorbs contaminants. To remove the endocrine disrupting herbicide Atrazine, make sure the filter is certified to remove it.
- Avoid non-fermented soy, especially if you're pregnant. Also, never use soy-based infant formula.
- Optimize your (and your child’s) vitamin D levels. As mentioned earlier, a 2011 study found that girls who are vitamin D deficient may be more than twice as susceptible to premature puberty as girls with optimal vitamin D levels.
- Store your food and beverages in glass rather than plastic containers, 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, and never microwave your child’s food in plastic containers. (It’s best to avoid microwaving food altogether.)
- Make sure your baby's toys are BPA-free, such as pacifiers, teething rings, and anything your child may put in her mouth.
- Use only natural cleaning products in your home to avoid phthalates and other toxic ingredients.
- Switch over to natural brands of toiletries such as shampoo, toothpaste, deodorant, and cosmetics. Avoid all fluoride-containing products and fluoridated water. The Environmental Working Group's Skin Deep Database22 is a great resource for finding personal care products that are free of phthalates, parabens, and other potentially dangerous chemicals.
- Avoid using artificial air fresheners, dryer sheets, fabric softeners, and synthetic fragrances.
- Replace your non-stick pots and pans with ceramic or glass cookware.
- When remodeling your home, look for "green," toxin-free alternatives in lieu of regular paint and vinyl floor coverings.
- Replace your vinyl shower curtain with a fabric one.
- When buying new products such as furniture, mattresses and infant cribs, or carpet padding, ask what type of fire retardant it contains. Be mindful of and/or avoid items containing PBDEs, antimony, formaldehyde, boric acid, and other brominated chemicals—all of which can have an adverse effect on your hormones. As you replace these toxic items around your home, select those that contain naturally less flammable materials, such as leather, wool, and cotton.
- Avoid stain- and water-resistant clothing, furniture, and carpets to avoid perfluorinated chemicals (PFCs).