Scrubbing yourself clean with triclosan-saturated antibacterial soap may be a bad deal for your immune system. And so might BPA, which lurks in canned-food linings and cash-register receipts, among other places.
"Hygiene clearly has very important benefits for protecting ourselves from infection," says Clayton. "But some of the chemicals in cleaning products and hygiene products may have more risks than benefits." How these chemicals actually interfere with the immune system is unclear, Clayton says. But one thing her results do suggest "is that the timing of exposure to BPA and perhaps the length of time someone's exposed may be affecting immune-system response." So older adults who've been exposed to BPA their entire lives are more likely to suffer immune problems than younger kids are (but at the same time, BPA has other effects on small children, including behavioral problems, so parents should avoid exposing children to it as much as possible).
Read More: How Antibacterial Chemicals End Up in Your Food
The good news about triclosan (the active ingredient in antibacterial products) is that once you stop using products containing it, the levels in your body drop relatively quickly. BPA isn't quite so easy to avoid. The World Health Organization recently declared food as our primary source of exposure to BPA, but a study published last year found that people who'd fasted for 24 hours still had somewhat high levels of BPA in their bodies. It's presumed that we excrete BPA within six or so hours of consuming it, so those results suggest that it either isn't excreted as quickly as thought, or that we're constantly being exposed to the chemical through other nonfood sources, such as ATM and cash-register receipts and the flame retardants used in mattresses and furniture.
To avoid BPA, limit your consumption of canned foods, don't microwave in plastic containers (BPA is a component of some plastics), and avoid other known exposure sources, such as receipts. Decline receipts at the ATM, gas stations, and any other retail outlet that gives you the choice. When you do get a receipt, store it in a separate envelope, rather than in your wallet.
To avoid triclosan, avoid all products labeled "antibacterial" or "antimicrobial." The chemical is listed as an active ingredient in all personal-care products in which it's used. But triclosan is also added to household goods as diverse as cutting boards and garden hoses. Keep an eye out for terms like "Microban" or "Biofresh" as both are trade names for triclosan.