Heavy metals, such as lead and mercury, may be a concern as these have proven to affect brain growth and development in children. Most of the time we’re not aware of their presence. Lead are found in paint in building built before 1978, or lead pipes in old buildings, or paint in toys imported from other countries. Mercury may be found in “silver” tooth fillings (amalgam) and a variety of seafood.

Lead is one of the most studied toxins in relation to mental disorders, such as conduct problems, IQ and ADHD. Lead’s effects on childhood IQ, ADHD, and conduct problems as well as physical health have been of concern for decades. We now know a great deal about how lead affects the brain, including disruption of signaling in the prefrontal cortex and striatum.

Many studies using different methods between 2005 and 2015 had confirmed that blood lead level was associated with ADHD even at levels in the 0.5 to 3.0 µg/dL range, after control for other factors.  

The mean lead level in these studies were well below the Centers for Disease Control and Prevention recommended safe level of 10 µg/dL.

Therefore, a “safe” level of lead for children would be “undetectable” on the current testing equipment. Any detectable level should be monitor and further investigated. 

Most children in the US (about 70%) are exposed to lead through lead paint in older houses, schools, and other buildings built before 1978; from surrounding soil and dust, which has accumulated and bound lead over the decades from airborne pollution. 

Other sources of exposure include water (leaching from lead in pipes, as in the recent Flint water crisis); and lead in imported toys, jewelry, candles, canned foods, candy wrappers, cosmetics, and poorly regulated dietary supplements. 

Children who live near airports are exposed to air polluted with leaded jet fuel from airplanes.

When your child has ADHD, consider checking your environment for possible sources of lead as listed above and make correction as much as possibly can. 

There’s a study that showed children who are exposed to higher levels of mercury in the womb are more likely to show attention problems, hyperactivity, and other ADHD symptoms when they’re 8 years old.

Researchers measured the mercury levels in the mothers’ hair shortly after birth, and found that a child’s risk of ADHD symptoms increased by 40% to 70% past a certain exposure threshold (1 microgram per gram).

The health effects of mercury toxicity are dependent on a variety of factors including the form and amount of mercury and the developmental age of the person being exposed. 

Methyl mercury, the type found in contaminated fish and dental amalgam, are readily absorbed by the body and accumulates.

Majority of the mercury exposure comes from eating fish from mercury-contaminated waters. This is why the U.S. Food and Drug Administration recommends that pregnant women eat no more than two six-ounce servings of low-mercury fish per week.

Smaller, oily fishes such as salmon, herring, mackerel, and sardines tend to be low in mercury and yet high in omega-3s, which is beneficial for preventing ADHD in unborn child. 

Shark, swordfish, and fresh tuna, on the other hand, contain high levels of mercury and a relatively modest amount of omega-3s. Therefore, should be avoided. 

“Thimerosal” is mercury found in vaccines, which is made of ethyl mercury. Ethyl mercury is less likely to accumulate and cause ill effects compared to methyl mercury because it is eliminated from the body much more quickly.

Mercury are also found in many common everyday products, such as batteries, measuring devices, such as thermometers and barometers, electric switches and relays in equipment, lamps (including some types of light bulbs), skin-lightening products and other cosmetics.

Organophosphate insecticides are one of the most commonly used pesticides worldwide. You’ll find it in just about anywhere, homes, veterinary offices and farms. 

Organophosphate interferes with the acetylcholinesterase enzyme (AChE), causing too much acetylcholine (ACh) to accumulate. This results in behavioral changes, respiratory issues and coordination problems when it affects the central nervous system (CNS).

Most people get exposed to organophosphates just thought eating contaminated food and water. Children are at much greater risk for organophosphate toxicity because the developing brain is more susceptible to neurotoxins than mature adults, and the dose of pesticides per body weight is likely to be larger for children. 

Organophosphate exposure in children has been linked to multiple problems, though the type varies depending on the time of exposure. Bouchard et al. notes that “

It is also known that exposure to organophosphate during pregnancy was associated with increased risk of pervasive developmental disorders, as well as delays in mental development. 

Exposure to organophosphate after birth has been associated with behavioral problems, such as poorer short-term memory and motor skills, and slow reaction times in children. 

It is well known that certain commercially produced fruits and vegetables are loaded with significant amounts of organophosphates, and should be avoided. 

Each year the Environmental Work Group publishes a list of produce to avoid and buy organic only called “The Dirty Dozen”. 

Prenatal nicotine exposure increases the risk for children developing attention-deficit/hyperactivity disorder (ADHD) later in life. Higher levels of nicotine were associated with a greater risk for ADHD, and the association between smoking and ADHD has a dose-response effect.”

Children born to women who smoke cigarettes during pregnancy, especially when mothers are heavy smokers, are at an increased risk for attention-deficit/hyperactivity disorder (ADHD).

Mothers who smoked during pregnancy had an overall 60 percent higher risk of having a child with ADHD compared to women who didn’t smoke.

Seven studies showed that while mothers’ smoking had a greater effect than fathers’ smoking on ADHD risk, there was still a 20 percent higher risk of ADHD in children born to fathers who smoked.

Bisphenols A or BPA is another dangerous food additives for ADHD that disrupts hormonal systems. BPA, a petrochemical derivative used to stiffen plastics, but it acts like estrogen in the body.

BPAs can act like the hormone estrogen and interfere with puberty, fertility and increase risk of hormone-related cancers. 

Bisphenols can also increase body fat, and cause problems with the immune system and nervous system resulting in behavioral and metabolic disorders.

According to a study published in the journal Environmental Research, children with high levels of the chemical bisphenol A in their bodies were more likely to have ADHD than those with lower levels..

Bisphenols are found in the lining of food and soda cans to prevent the metal from eroding. They’re also found in plastic containers labeled with number 3 or 7. 

Can you imagine these were used to be in plastic baby bottles and sippy cups too? Fortunately, that’s history. BPAs are banned, but older bottles and cups may still contain them. 

EWG published a report that reveals more than 16,000 processed foods may be packaged in materials that contain BPA. People are also exposed to BPA by thermal cashier receipts.

Working in the pediatric clinic, I see that kids as young as 1 year old using an electronic device. We always joke about how parents use iPad or tablet as babysitter. 

Two studies looked at the association between television and video game exposure and ADHD. 

The Japanese study found that children with high levels of television viewing at 18 months of age had greater hyperactive and inattention symptoms at 30 months of age compared with those with low exposure. 

The other study looked at the association between hours of television and video game use and attention problems in both school-aged children (N=1,323) and young adults (N=210) and found an association between higher total screen time (television plus video games) and increased attention problems. 

One day I picked up my daughter from after school care as usual. She was unusually energetic and talkative that day. Usually she’d just get into the car asked about what’s for dinner. She might tell me a few things that happened in school that day. 

But this day was different. It’s almost like her motor was on high gear. She talked at way higher speed than her usual with extra energy level, which I have not seen in her before. 

This happen a few more times, and I finally figured that it’s the pepperoni she ate at the after school care. 

After that, no more pepperoni or deli meats for her, or anything with food additives. 

There are many possible causes of ADHD, and environmental toxins is one that’s frequently ignored. 

Most people’s idea of environmental toxins, they’re thinking about the air and water we breathe, but it’s everything that we interact with everyday – air, water, food, furniture, people, etc. 

Related: 12 Toxic Food Additives to Avoid for ADHD

What to do now?

Environmental toxins are everywhere. The best tools we have is to educate ourselves and make the best choices for our family and children. Follow a real food diet that is filled with wholesome uncontaminated meats, nuts, seeds, fruits, and vegetables to provide the basic vitamins and minerals that your body needs.

1. Eat nutrient-dense real unprocessed food

No time to cook? Use a meal planning app to plan your meals, grocery shopping list, and cooking schedule so you can cook once and eat healthy, delicious, and affordable meals all week. 

2. Choose organic produce and meats when possible to avoid pesticides, growth hormones, and antibiotics. 
3. Use glass or stainless steel containers instead of plastic containers for storage to avoid BPA exposure. 

Check out these BPA-free glass food containers and these stainless steel food containers from amazon.com

4. Do not heat food in plastic containers in the microwave. The high temperature causes the BPA to be released into the food.
5. Use organic toxin-free cleaning products if possible