Child Development
5 Questions With Dr. Tavyev-Asher: Neurotoxins On Our Mind

5 Questions With Dr. Tavyev-Asher: Neurotoxins On Our Mind

January 18, 2023

By Alexandra Zissu, Editorial Director

Childhood is the time when we’re most vulnerable to the effects of environmental pollutants, and few types pose a greater threat to healthy development than neurotoxins, which harm growing brains and nervous systems. Recently, we had a chance to ask Dr. Jane Tavyev-Asher, Director of Pediatric Neurology at Cedars-Sinai Medical Center, a few questions about this crucial subject.

Tell us a little bit about how environmental toxins affect developing brains.

The human brain grows to nearly 90% of its adult size by age 3. At no other time in our life is there such a radical amount of change happening in such a short window. Environmental toxins can impact this process either by direct damage to the DNA (the “instruction book” for this process), by hormone mimickers (which act as “false messengers”), or via epigenetic changes (altering which specific parts of the “instruction book” will be read). Envision a factory with an automated process making cars. If the factory makes one car per day, then an error one day would only affect one car. If the factory makes thousands of cars per day, then one small error will suddenly impact all of those cars. This is what its like to affect the delicate rapid process taking place in the prenatal period and early childhood.

There have been some suggestions that environmental toxins are contributing to the startling rise of autism in the U.S. What’s your view on this issue?

As we have not yet been able to definitively prove a link between environmental toxins and autism, there are two ways to approach this question. This first is to examine the genetic changes shown to cause autism. We can then ask, “What in our environment is causing these genetic changes?” The second way is to look at which chemicals might do direct damage to brain cells by a variety of mechanisms. If the cells of the brain are damaged during the critical window of development, we might suspect that autism may result. The top toxins currently being implicated as doing damage to brain cells include lead, methylmercury, PCBs, organophosphate pesticides, organochlorine pesticides, phthalates, bisphenol A, automotive exhaust, polycyclic aromatic hydrocarbons, and brominated flame retardants. Perhaps not surprisingly, many of these same chemicals are also linked to cancer risk.

What do you think the next big toxicological issue in this area is likely to be?

While I’m not entirely sure what the next “big toxin” may be, I do have ideas on how to reduce the impact of toxins on our bodies. I believe that inflammation may be playing a role in making us more vulnerable to the effects of environmental toxins, and that this process plays a global role in our health, including neurologic disorders, cancer, cardiac health, obesity and even mood disorders. Our diet today has a much higher Omega 6 to Omega 3 ratio than it did decades ago. Omega 6 sets off a cascade of factors that leads to inflammation, while Omega 3 is felt to play an anti-inflammatory role. Animals that are meant to graze on grass are being fed corn and soy, and this makes their meat have a much higher ratio of Omega 6 to Omega 3. As we consume the beef, chicken, milk, cheese, and eggs from these animals, we are tipping the ratio of inflammation vs. anti-inflammation in the wrong direction. We may be able to modulate this effect by eating grass fed beef and free range chicken, and their byproducts, by cooking in healthier oils such as olive oil and coconut oil and by eating more foods that contain Omega 3 fats such as nuts, chia seeds, and hemp seeds. Exercise is also an incredible way to reduce inflammation in our bodies, and yoga and meditation reduce stress, which also results in less inflammation.

What toxins pose the biggest threats to neurological health and development?

Certainly lead has the most evidence behind its directly deleterious effects on IQ and mood/behavior. The next place to look is at our food supply, which often exposes us to PCBs (via water and fish), pesticides, phthalates, BPA (which can be part of our food packaging and presentation), and polycyclic aromated hydrocarbons (which can be found in overcooked foods).

What advice do you have for parents who want to be proactive about protecting their families from neurological harm?

The biggest impact is made by the earliest changes. I feel that the prenatal period and even the several months preceding conception are the most critical. Drinking filtered water out of glass containers can reduce exposure to PCBs and other toxins. If you prepare your meals at home, you can avoid foods in plastics or cans and reduce BPA and phthalate exposure. Organic fruits and vegetables reduce pesticide exposure, and you can control the cooking method and source of fish [to] reduce exposure to PCBs and PAH. I also advise eliminating most beauty products or switching to those free of harmful ingredients. The final thing is simply washing your hands! We are exposed to many of these toxins through things that we touch. Washing our hands often will help. Even if you don’t think your hands are “dirty,” make sure you wash before every meal or snack!

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