Understanding the Impact of Toxins on the Brain & Brain Development

And, Why the Brain is a Good Barometer of "Oxidative Stress."

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Recently I saw a humorous reel of a man going through his day. As he does, you hear his inner dialogue. He’s trying to prepare a healthy snack, but at every turn, he’s stopped by his voice pointing out exposure to toxins - in the packaging, the water, the skin of the fruit. Eventually he sits down and opens a bag of chips.

Can we lower our exposure to toxins (and support detoxification) and not live in fear? I think we can. We can all hold this heavy topic lightly and do the best we can, knowing that there’s no perfection here.

“If we are going to live so intimately with these chemicals, eating and drinking them, taking them into the very marrow of our bones - we had better know something about their nature and their power.” - Rachel Carson in “Silent Spring” (1962)

In this newsletter, I'd like to help you better know something about the nature and power of the chemicals and heavy metals that we’re exposed to. I’ll discuss

• The cumulative effects of our exposures

• Sources of toxins

• Oxidative stress

• How toxins contribute to chronic health conditions, including psychiatric conditions

• Impacts on the developing brain

• How oxidative stress can be measured

In a future newsletter, I’ll dig deeper into ways to avoid exposures and ways to support our organs of detoxification and antioxidant systems.

How Toxic Are We?

From the EPA / Environmental Protection Agency - Of the more than 40,000 chemicals used in consumer products in the US, less than 1% have been rigorously tested for human safety. (Here is the US, the approach is to put chemicals into food and other products and not study, regulate or limit them unless health concerns arise).

For those few chemicals that have been banned, we can still be exposed. For example, we continue to be exposed to DDT- a pesticide banned because of concerns about its impact on human health. It has polluted the earth’s atmosphere, oceans, streams, and wildlife.

We come into the world with a toxic load. The Environmental Working Group’s “Body Burden” 2004 study found an average of 200 industrial chemicals in umbilical cord blood per baby. These included polyaromatic hydrocarbons, dioxins, furans, pesticides, chemicals from flame retardants, industrial lubricants, plastics, consumer product ingredients, and wastes from burning coal, gasoline, and garbage.

The following toxins are found in almost all children

• Mercury - 89%

• Lead - 100% The more present, the lower the IQ. Now, it is agreed there is no safe level of lead.

• PCB’s (banned in the 70’s but still around) - 100%

• BPA - 96%

• PBDE’s flame retardants - 100% of children. As body burden increases, a child’s IQ decreases.

• Organophosphate pesticides - As the body burden increases, the IQ decreases.

Toxins & Their Impacts Add Up

Toxins are problematic for all of us, but especially for those of us whose brains are in the process of being formed. The chemical industry says the effect is subtle and of little consequence.

If, however, you consider a bell curve for intelligence and you shift it to the left because of lead exposures and then you shift it to the left some more because of organophosphate pesticides and then again for PBDE flame retardants, our collective drop in IQ and human potential becomes much more striking. And that’s just when you're only considering 3 studied toxins and only when you're considering IQ and not things like self-regulation or behavioral control, coordination, or even empathy.

Sources of Toxicity

This is worth considering, again, not to live in fear, but to lower our exposure…in a very matter of fact and relaxed way. Fear doesn’t lower our toxicity, it more likely slows our detoxification.

Exotoxins - Toxins that we ingest, inhale, or absorb from outside of us

• The air we breathe - e.g., mold toxins if water damage in a building, pesticides, if we live near farms or use certain household products, or heavy metals in areas with a heavy traffic

• The water we drink - e.g. heavy metals, chemicals

• The food we eat

  • Pesticides, herbicides

  • Additives, preservatives

  • Chemicals from packaging

• The products we put on our body, face, hair. For example, most lipsticks contain lead. A recent study found heavy metals in common tampon brands

• The products and chemicals we use in our house (cleaning solutions, fragrances) or on furniture and clothing (flame retardants)

Endotoxins - toxic chemical by-products of microbes in our gastrointestinal tract.

Examples could be mold (in our GI tract or sinuses) and yeast, however, even some beneficial microbes can release chemicals your body must manage.

These all add up.

What Is Oxidative Stress?

Oxidative Stress occurs when the toxic load in our body is greater than our body’s inherent defense mechanisms can handle. The toxic load might be heavy metals like lead, mercury, cadmium, or arsenic, microbes such as viruses, bacteria, and fungi, injury, inflammation, EMF, and/or emotional stress. On the deepest biochemical level, oxidative stress is when our inherent antioxidants are insufficient for what they face, namely an excess of chemical free radicals.

Free radicals:

• Highly reactive, unstable atoms or molecules can damage or destroy proteins, cells, DNA, and other essential biochemicals.

• They cause damage by stealing electrons from other atoms in cells

How Toxins Can Cause Damage

• Displace minerals - such as displacing calcium in our bones, resulting in weaker bone structure. With bone loss (in the 40’s and beyond), those toxins are released into the rest of the body.

• Damage enzymes, so they don’t work right. Our bodies depend on enzymes to make things happen. All of our physiologic processes depend on the functioning of enzymes.

• Damage cell membranes, which affects their signaling and communication.

• Damage DNA - think cell death, aging, and degeneration

• Damage organs - including those organs that are necessary to detoxify (gastrointestinal tract, liver and kidney) and the brain

• Impair our ability to detoxify

• Cause inflammation with all of it’s consequences (including disrupted communication between nerve cells and neurodegeneration)

• Impact gene expression

• Interfere with hormone receptors on cells

• Deplete our protective antioxidants making us more vulnerable to future exposures.

Developmental & Other Brain Impacts

Children are especially vulnerable to toxins such as metals, as their blood-brain barrier has not matured. Developmental consequences of high oxidative stress include autism, decreased IQ and/or ADHD and behavioral issues.

Chemical toxins can interrupt neuronal connections, and interfere with the development of brain cells and their receptors that neurotransmitters (serotonin, dopamine, and GABA) bind to. This impacts cellular communication. High oxidative stress can also deplete two of the main antioxidants, glutathione (GSH) and metallothionein (MT). You’ve likely heard about glutathione, but metallothionein proteins are pretty amazing as well.

• Metallothioneins

  • Required for pruning, growth, and growth-inhibition of brain cells in early development. This is required for the development of brain cells and synaptic connections.

  • Prevents mercury and other toxic metals from passing the intestinal and blood/brain barriers.

  • Supports immune function

  • Regulates the homeostasis of copper and zinc.

  • Prevents casomorphine and glutomorphine getting into the brain, which causes inflammation.

Degrees of Vulnerability

Not all children with the same exposures in utero or after birth will develop autism or ADHD. Not all adults with the same exposure will develop mental illness, dementia, cancer, cardiovascular disease, autoimmune conditions, obesity, diabetes, other chronic disease or accelerated aging.

We all vary in terms of our ability to detoxify. Given the same exposure, some of us (at times very few) will be hit very hard. This may be because of the difference in our nutritional status, which we come by, in part, genetically, but also by what we eat and how healthy our microbiome is. We differ in terms of how permeable our first line of defense - our gut is, which can have to do with how inflamed our gastrointestinal tract is, how healthy our microbiome is, but also the integrity our connective tissue (which holds us together). We all have varying degrees of functioning of liver enzymes involved in detoxification, and vary in terms of how much glutathione we make or have available. We vary in how much our inherent antioxidant system’s capacity has been used or depleted. Do we have a lot of reserves, or is our system overwhelmed and unable to protect us?

We vary in how much emotional trauma we’ve experienced and hold in our bodies - more specifically, our autonomic nervous system. Chronic stress hormones and an overfunctioning of our sympathetic nervous system can keep our detox organs from working at full speed.

We can also vary in how much stored toxins are becoming mobilized. Toxins can store in our brain, bones, blood, and fat. Toxins in fat can become mobilized when we lose weight, while toxins in the bone can be mobilized when we start having bone loss (beginning in the forties). While many toxins can move out of our body quickly, many stay in our cells, our bones or fat and take longer to remove.

We also vary in where we live in the world, and our socioeconomic status. The European Union has stronger regulations on chemicals than the US. You won’t find Mountain Dew and chlorine-washed chicken in the EU. If you’re eating Skittles or M&M’s in Europe, they’re colored with natural ingredients like turmeric, but if you're eating them here in the US, you’re ingesting Yellow Dye no. 5 and no. 6, which have been linked to allergic reactions, as well as hyperactivity in children. Not surprisingly, we have more chronic health conditions here in the US.

Markers of Oxidative Stress:

You might be wondering - “Can we prove that someone has high oxidative stress, beyond their having a chronic health condition or psychiatric condition?” We actually can measure oxidative stress. A good example of this type of research comes from the Walsh Research Institute.

After evaluating 6500 individuals with autism spectrum disorder. Dr. William Walsh looked at around one hundred chemical factors using blood, urine, and hair. Of 800,000 chemical test results, he found the following biochemical imbalances (relative to healthy controls). Each is associated with elevated oxidative stress.

• Decreased Glutathione and Cysteine

• Elevated toxic metals

• Depressed SAMe/SAH Ratio

• High copper and low ceruloplasmin

• Depleted zinc and Metallothionein (MT carries zinc around, and they are often low together)

• Elevated pyrroles

• Low B6, C, and Selenium

• Elevated Urine Isoprostanes (damaged fats - DHA)

The Collective

Despite our differences in vulnerability, this topic of oxidative stress is about all of us all the time. It’s about the toddler in an inner city apartment putting lead dust from old paint in their mouth, and the child in the suburbs rolling around in the grass doused with pesticides. It’s about the teens using toxin containing body products and the adults spraying Round-up on their yard.

To some degree, we are all managing or not managing, the toxic load we've been handed. The best we can do is to be informed and do the best we can….without having it rule our life.

In a future newsletter, I’ll share:

• ways to limit exposures

• ways to support our organs of detoxification

• ways to support our antioxidant system

Until next time

Courtney

CourtneySnyderMD.com