Are you having little luck in the search for your soulmate? When you finally meet a woman does she seem disinterested? What could it be? Your breath? Your clothes?
This is not an ad in the personals. It's the opening line of the commentary in the straitlaced scientific journal, Proceedings of the National Academy of Sciences (PSAS). The authors, neuroscientists Liisa Galea and Cindy Barhain, intend to shock. Why, one wonders, would a man have no luck in love?
Findings from a new study suggest it may be your mother's dietary exposure to bisphenol A (BPA).
Galea and Barha have all my attention now. Ever since my pregnancy, I have been tracking studies on BPA's subtle yet shocking effects. One of the most common chemicals in the world, bisphenol A is found in the stuff we use every day of our lives. Soup and soda cans. Water pipes. Computers. Cell phones. Thermal paper receipts. Paper money. Even some baby bottles—at least in the U.S., because they are not banned here.
Much of the trouble with BPA lies in its ability to fool estrogen receptors into thinking it's estrogen. Imagine a man doesn't know that the woman he's marrying is really an alien in drag, and you have a sense of the danger here. BPA disrupts any process that estrogen normally mediates, affecting brain, body, and behavior. It also tinkers with the way genes express themselves, turning up those that would otherwise be turned off or down. BPA exposure has been linked to breast cancer, heart disease, obesity, diabetes, attention-deficit disorder, increased anxiety, a decreased IQ in children and a low sperm count in men.
Pregnant women and new moms should be especially cautious. BPA has been found in umbilical cord blood and in breast milk. It crosses the placenta and flows in fetuses. Young bodies are especially vulnerable to pseudoestrogens. The toxin strikes us moms, too. Researchers worry that BPA may affect women's brains in a way that alter their maternal instincts. In laboratory studies, BPA-exposed female rats are less likely to nurture their offspring—they lick them less—which in turn affects the emotional and cognitive system of their babies. They become more fearful and anxious.
And now, there's more.
There is evidence that BPA emasculates males and makes them sexually undesirable. Galea and Barha's opening lines in PSAS are tongue in cheek—they are describing a new study at the University of Missouri on the effects of BPA on deer mice—but the application to humans is implicit. Adult mice whose mothers were fed a dosage of BPA equivalent to what the USDA deems safe for pregnant women, were, well, different from other males.
"One of the prominent effects of early BPA exposure is that it eliminates a number of sex differences in brain and behavior," the researchers wrote. It turned out that BPA-exposed males have impaired spatial ability (can't find their way out of a maze or to their nest, considered unattractive to females). They also suffer from decreased exploratory ability (incurious and easily lost), and overall reduced attractiveness to the opposite sex. They may even smell different from their peers—in rodents, a sign of unhealthiness. Females are disgusted.
It's not absurd to worry about similar effects of BPA-exposure on our babies. Men are not mice, but there is increasing evidence that BPA affects us as well, and in doses below the 50 µg/kg/day safety threshold in the United States. Almost every American pregnant woman (93 percent) has detectable BPA in her body, which is passed on to her fetus. The average BPA body burden of an American is high, alarmingly high, compared to other countries. We love our BPA-enriched Cokes and canned Campbell's soups.
On a population level, how might BPA affect us? Might boys in the U.S. grow up to have poorer spatial skills—and, because it's linked, weaker mathematical ability? Might they have little interest in exploring the world, preferring to hang out at home? Might our national temperament become more placid? Because BPA is lined with obesity and heart disease, will we become fatter and more sedate? And what about our sex lives?
Take a look at human history through the lens of hormones, as Harvard University's Daniel Lord Smail did in his fascinating book, On Deep History and the Brain. Smail introduces a new view in which physiology and culture evolve symbiotically in a process driven by brain chemistry. Caffeine stimulated the body and mind, driving the industrial revolution and the modern corporation. Tobacco help us to focus and be calm. These substances changed the character of society. Now we have environmental toxins such as BPA (and other hormone disruptors such as phthlates and PCBs) that may also change our culture in subtle but very real ways.
BPA: Bad for your manhood. Bad for your sex life. Sensationalistic, sure—but would this get CEOs to pay attention? Hit them where it hurts.
Stubborn pushback—that's the response from many corporations regarding BPA bans. The chemical is a mainstay in packaging, and to ditch it is disruptive for business. Coca Cola has famously refused to find an alternative. You can find BPA-free cans of beans from brands such as Eden, but not crushed tomatoes yet (in the meantime, buy them in glass jars). Avoid plastics that are marked with recycle codes 3 or 7; they may contain BPA. While Canada, Europe, and even China have banned the use of the chemical in baby bottles, the U.S. has not (although consumer demand has pushed many manufactuers to go BPA-free).
The good news, as I describe in my book, is that there is laboratory evidence that a diet high in folic acid and B12 may reverse at least some of the nasty effects of prenatal BPA exposure. How? One way that BPA tinkers with gene expression is by attaching itself to DNA and "turning on" certain genes (removing methyl groups) that are normally turned off—resulting in obesity, cancer, and other problems. (This is classic epigenetics—an environmental trigger affects the way that genes behave.) Nutrients in green vegetables, beans, eggs, and soy may be protective (in those of us who include enough in our diet) because they turn off genes that BPA otherwise turns on.
Of course, the best protection is to turn corporations off BPA. That would really be a turn-on for us moms.
*If you like this blog, click here for previous posts. If you wish, check out my new book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.