Scientists are racing to find an answer to this question: How do you get autism? Increasingly, they're finding that when it comes to autism, ADHD, and learning disabilities, genetics is only part of the story. In fact, in trying to figure out the sources of autism, researchers are proving that environmental factors--everything from farm chemicals to soda and shampoo ingredients--could be permanently messing with children's brain development. Today, in an unprecedented move, some of the world's leading experts published a new list of highly suspect chemicals and heavy metals believed to be behind the surge in cases of autism and other neurodevelopmental diseases. "We have very powerful, very sophisticated tools we can use to measure chemicals at very low levels," explains Phil Landrigan, MD, coauthor of the list and professor and chair of preventive medicine at Mount Sinai Medical School in New York. "It's now possible to connect early exposure to problems in childhood."
Dr. Landrigan says the goal of the list, published in Environmental Health Perspectives, is to inform more doctors and nurses about the environmental triggers of autism, to increase funding for more studies, and to ultimately change chemical regulation in this country to better protect our children.
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This heavy metal has been shown to cause brain damage to developing babies, causing a lifetime of learning and health implications. Lead is also linked to depression in young adults.
Where is it? The powerful neurotoxin is most often found in old paint, but can also leach from older plumbing.
Avoid it! Refrain from removing old paint if you're trying to become pregnant, are pregnant, or are breastfeeding, or if small children are in the house. If you fear your water contains lead, call EPA's Safe Drinking Water Hotline for help. In the meantime, a diet low in fat and high in calcium and iron, with foods like low-fat dairy and leafy green vegetables, can help block some harmful lead exposure.
The mercury created from coal-fired power plants winds up in rivers, streams, and oceans; the heavy metal is toxic to the brains of developing fetuses and could cause irreversible damage.
Where is it? The damaging form of mercury accumulates in species of fatty fish that grow to be large and higher up the food chain; consuming these fish is the No. 1 source of human exposure. Mercury has also been detected in high-fructose corn syrup.
Avoid it! Choose healthier options from the superfish list, including wild-caught Alaskan salmon or Pacific wild sardines.
Once used in electronics, PCBs bear the unfortunate distinction of never breaking down in the environment. And a little of them can do a lot of damage: Small doses can disrupt healthy nerve cell functioning and throw off the body's natural calcium signaling, which could increase some children's autism risk.
Where is it? PCBs are found all over the environment--and inside most of us.
Avoid it! Eat lower on the food chain; PCBs accumulate in animal fat. Removing fish skin and trimming fatty parts of meat can help cut back on your family's PCB exposure.
The now-banned DDT is the most notorious organochlorine pesticide, but others in its class remain in use and are implicated in birth defect and autism clusters.
Where is it? Mostly causing damage in farming communities, this type of bug-killing chemical has been linked to an increased risk in autism among children born to mothers living in high-spray agricultural areas.
Avoid it! Support organic farming to reduce your risk of eating pesticide residues, as well as to protect people who live near or work on chemical farm operations. Children's greatest organochlorine exposure comes from conventional snap beans, tomatoes, and watermelons, so especially concentrate on sourcing these produce items organically.
Learn More: Organic Can Heal Bodies & the Planet
Recent studies link air pollution from vehicle exhaust to memory problems, brain damage, and an increased risk of autism. A prior study found that children born to women living within 1,000 feet of major highways are twice as likely to be diagnosed with autism years later.
Where is it? In the air in areas exposed to heavy traffic.
Avoid it! Drive less or carpool to cut back on air pollution, commute during less busy hours, and if you live close to a major roadway, consider investing in a high-quality air purifier that does not produce ozone, such as IQAir models.
Read More: The Best Reason to Telecommute
Created to slow down the rate of burning in the case of a household fire, flame retardants are largely useless and have been shown to actually hasten death from smoke inhalation. Over the long term, children born to mothers with high levels of these chemicals in their bodies have lower IQs and perform more poorly in mental and physical development testing.
Where is it? They're found in furniture, electronics, certain sodas and sports drinks, and even household dust.
Avoid it! Avoid furniture that meets California's TB117 law, a regulation that promotes the use of flame retardant chemicals. Be diligent about wet-mopping in the house and use a HEPA-filter-equipped vacuum to reduce flame retardant--laced dust. Opt for natural flooring materials, not carpeting and carpet padding, which could harbor flame retardants. As for the beverage aisle, steer clear of Mountain Dew and certain Gatorade and Powerade flavors that list BVO--brominated vegetable oil, a flame retardant--as an ingredient.
Read More: 9 Disturbing Soda Facts
Carcinogens that are formed when meat is burned, PAHs are also among a category of 10,000 chemicals created from the burning of oil, garbage, coal, or wood. The compounds can damage DNA, hamper normal development, and impair fetal growth.
Where is it? Aside from burned meat, PAHs are abundant in coal-tar-based driveway sealants and anti-dandruff shampoos, cigarette smoke, and mothballs.
Avoid it! Opt for nontoxic mothball alternatives, shun cigarette smoke, and look for safer driveway sealants that are free of coal-tar ingredients. Use rosemary marinades for meat to deter carcinogens from forming on meat cooked at high temperatures.
Read More: 12 Household Toxins You Should Banish from Your Home
Chlorpyrifos, an organophosphate insecticide, is still one of the most widely used farm chemicals in the U.S.
Where is it? Banned from residential uses, this pesticide is still legal in agriculture, and residues have turned up on apples, bell peppers, cranberries, kale, grapes, peaches, and dozens of other foods.
Avoid it! Eat organic as often as possible. Studies have proven that pesticide levels in the body plummet when consumers switch to an organic eating regimen.
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Prenatal exposure to even tiny doses of hormone-disrupting chemicals could irreversibly alter a child's health.
Where is it? Bisphenol A (BPA) and plasticizing chemicals called phthalates are prime suspects linked to socialization and aggression problems in children, along with stunted growth, learning disabilities, and lower IQ. These chemicals are used in hundreds of everyday products, including soaps, shampoos, cleaners, and air fresheners.
Avoid it! Keep BPA out of your system by avoiding canned foods and beverages, as well as No. 7 plastics. To reduce phthalate exposure, nix scented candles and air fresheners, and avoid personal care products that list "parfum" or "fragrance" as an ingredient.
Read More: What is a "Hormone Disruptor" Anyway?
More studies cropping up suggest the convenience of nonstick cookware might not be worth the anticipated health costs: ADHD in children and high cholesterol and infertility issues in adults.
Where is it? In nonstick cookware, waterproof clothing, and certain stain-repelling fabrics used in carpeting and furniture.
Avoid it! When you start seeing scratches and chips in your nonstick cookware, replace it with safer American-made cast iron or untreated stainless steel. Also, pass on furniture and carpet treatments offering stain protection.
Read More: The 9 Nastiest Things in Your Supermarket