In July 2002, a huge U.S. study considering the effects of long-term hormone replacement therapy on post-menopausal women was halted when the researchers concluded the risks of therapy (increased chance of heart attack, stroke and breast cancer) outweighed potential benefits. This was just the latest of a series of controversies surrounding the effects of hormone therapy in women. Researchers in the past decade have observed girls are reaching puberty earlier, meaning they are exposed to estrogen and other hormones for a longer period of time and are at a greater risk to develop breast cancer and other health problems.
Last April, New Scientist magazine reported some hair products, particularly those marketed to African-Americans, might contain hormones that cause premature sexual development in girls.
This means consumers are not sufficiently informed about the products they use—products which may have unintended and unknown side-effects.
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The onset of puberty in girls is marked by the appearance of secondary sexual characteristics: faint genital hair, breast tissue growth and increased growth rate. According to standard medical texts, girls younger than eight years who show such these are diagnosed as sexually precocious.
The fact that girls in the U.S. are reaching puberty earlier than previous generations is not easy to explain. While it is generally accepted that early onset of puberty is linked to better nutrition and hygiene, some researchers suggest the increased use of certain plastics and insecticides in the environment may be a contributing factor. These substances mimic the body’s hormones once they’re absorbed through the skin.
Synthetic forms of estrogen (found in hormone replacement therapy and birth control pills) and chemicals that act like estrogen (found in plastics and household chemicals) can disrupt the function of natural hormones and accumulate in fatty tissues and organs. Absorbing even tiny amounts of these substances at critical periods in development, especially in utero or during adolescence, when the body’s rapidly-multiplying cells are especially prone to chemical influence, can alter sexual, behavioural and neurological development.
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A cause-and-effect relationship is not easy to prove. “To date, no study has identified any specific environmental contaminants causing or contributing to precocious puberty,” said Jill Hamilton, a pediatrician at the Hospital for Sick Children. But she does point out many researchers suspect hormones in meat, chemical pollutants, and topical estrogen (found in certain hair products) may be the culprit.
Hamilton had a patient—a six-year-old boy—who showed signs of breast development after using a brand of hair sheen from his mother’s native Jamaica. “It likely contained estrogen, but we have only speculated this, as we could not test the product.” But the breast tissue disappeared after her patient stopped using the product.
Chandra Tiwary, former chief of pediatric endocrinology at Brooke Army Medical Center in Texas, also believes there is a strong link between hormone-rich hair products and early puberty. “I believe that the frequency of sexual precocity in childhood can be reduced simply if children do not use these products,” he told New Scientist.
In 1998, Tiwary published a study involving four girls—one a 14-month-old baby—who had developed breasts or pubic hair months after beginning to use such products.
Products containing hormones are classified as drugs in North America. Makers of any new drug must file an application for approval with federal regulatory agencies. But as reported by New Scientist, at least five companies are still making hormone-based hair products. This is because the U.S. regulation applies only to products introduced after March 1994. Any hormone-containing hair products marketed before that date could still be available to the public without having gone through the process of testing and approval.
For example, B&B Super Gro, a hair product that claims to be “rich in hormones,” was marketed before 1994 and is still available in the United States. Testing showed that for every 100 grams of the product, there were 1.6 grams of estradiol—a type of estrogen.
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Hair products are classified as cosmetics. In Canada, cosmetics are regulated under the Food and Drugs Act. The law requires that no manufacturer or importer sell a cosmetic that contains an estrogenic substance. Jane Goebel, a product safety officer for Health Canada, said, “Importers of cosmetics into Canada are required to submit a notification to Health Canada which includes an ingredient listing. Any notifications which include estrogen as an ingredient are rejected.”
It’s possible consumers may soon be able to see these ingredient lists for themselves. In February, Health Canada proposed an amendment to cosmetics-regulating legislation that would require both manufacturers and distributors to list ingredients on all product labels.
This is likely good news, giving consumers more control over what kind of chemicals they use. However, until researchers have more clear evidence about the effects of insecticides, plastics and hormone replacement therapy, eliminating hormones in hair products is a small step.
This is why many health experts advocate the precautionary approach: rather than waiting for a substance to be proven harmful before usage stops, it shouldn’t be used until it is proven to be safe.
With files from Leena Kendhari.
Illustration by Derrick Chow
