Environmental toxins cause trouble for your brain in a number of ways; creating free radicals and increasing brain-aging inflammation are among them. Your body has an efficient detoxification system and can eliminate many of the toxic health threats you face every day. But since experts aren’t sure how chronic, low-level exposure to the thousands of chemicals in our everyday environment interact with each other to affect us long-term, it makes sense to reduce your exposure—especially to known brain agers—whenever you can.
Estrogen and testosterone appear to play critical roles in cognition and mood by affecting synapse “plasticity,” which influences learning and memory and typically decreases with age. Endocrine disruptors like bisphenol A (BPA) and phthalates upset the delicate balance of hormones needed for your brain to work at its best. Combined with a natural decrease in sex hormones as you get older, studies suggest exposure to even low doses of endocrine disruptors may have widespread effects on brain structure and function, potentially speeding up age-related cognitive decline.
BPA is a synthetic substance used to create polycarbonate plastics, widely used in water bottles, food storage containers, and the lining of metal food cans, among other things. Research shows that it can leach into food and drinks, and that we are widely exposed to low, but continuous, levels. Most of the studies on BPA have been done on animals—usually rats—so researchers can’t say for sure that the effects are the same in humans. But a 2008 study by Yale University researchers found that administering BPA to monkeys at a daily dose equal to the current U.S. Environmental Protection Agency’s reference safe daily limit (50 micrograms per kilogram of body weight) interfered with synapse formation in the hippocampus and prefrontal cortex, two areas of the brain critical for cognition, attention, and memory. Phthalates hinder testosterone’s effects on the brain, and a 2009 study in the Journal of Applied Toxicology found that low levels decreased spatial learning and reference memory in male rats.
With this mounting evidence, experts agree your best bet is to avoid endocrine disruptors as much as possible to preserve brain health and function as you get older. Many manufacturers are phasing out BPA—most notably makers of baby bottles and water bottles—and will often state on the label that a product is “BPA-free.” Phthalates are frequently found in food packaging and plastic wrap, as well as personal care products like moisturizers, perfumes, hairsprays, soaps, and shampoos. You can reduce your exposure to these endocrine disruptors by using metal, glass, ceramic, or wooden products instead of plastic whenever possible, such as switching to glass or ceramic food storage containers. Also, avoid heating plastic containers in the microwave or running them through the dishwasher. Read the labels on personal care products and avoid those that list phthalates. Products that note “fragrance” on the label may include phthalates, even if they’re not listed specifically. To research a particular product, check the Environmental Working Group website (www.ewg.org), which features a database of cosmetics ingredients.
Chemical pesticides kill pests by attacking delicate nerve tissue. While they’re designed to be safe for humans in small doses, the residue gets stored in your fat cells and can stay in your body indefinitely. Over time, levels build up and can raise your risk of Parkinson’s and other neurological diseases. A 2008 study in the journal Chemico-Biological Interactions noted that chronic low-dose exposure to organophosphorus pesticides (the most commonly used class of pesticides in the United States) results in cognitive impairment. Pesticides can also age your brain by triggering inflammation and increasing damaging free radicals.
To limit your contact, avoid using chemical pesticides in and around your home (Organic Gardening magazine, online at www.organicgardening.com, has suggestions for effective natural pest control methods) and eat organic produce whenever you can. If you don’t have access to many organic foods or can’t afford to eat entirely organic, the Environmental Working Group website www.foodnews.org provides a list of the fruits and vegetables that have the most pesticide residue to help you figure out where you’ll get the most bang for your buck.