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  • Writer's picturePatricia Faust

Environmental Toxins Effect on the Aging Brain

Recently, the standards for car emissions were relaxed which would then threaten air pollution standards. Thankfully, the automobile industry rejected the new emission standards and will continue to develop and produce cars that are environmentally friendly. Why is this so important to me? We think of air pollution being a cause of lung problems. But the brain is directly impacted by air pollution.

Research on the Effects of Air Pollution on the Brain

I found a study published in the New York Times a while back that was titled “Pollution May Age the Brain”. There were 1403 women in this study who didn’t have any dementia diagnosis. The health study covered a ten-year period – 1996 – 2006. The participants ranged in ages from 71 – 89 years old when they had MRI scans to measure their brain volume. The comparative data used in the analysis included residential histories and air pollution data used to measure their air pollution exposure from 1999 – 2006. Previous studies had already confirmed that air pollution can cause inflammation and damage to the vascular system, but the results of this study demonstrated that air pollution can actually cause brain damage. As Dr. Jiu-Chiuan Chen from the Keck School of Medicine at the University of Southern California states, “Particles in the ambient air are an environmental neurotoxin to the aging brain.” This study was done in the United States.

This study really drove home how vulnerable our brains are to environmental influences. So, I looked further to see if there were other environmental factors that are placing us at risk for dementia. Not only did I find that our ever day products can put us at increased risk for Alzheimer disease but also other neurodegenerative diseases such as Parkinson’s disease and ALS (Amyotrophic Lateral Sclerosis) or otherwise known as Lou Gehrig’s disease.

When Our Brain Is Most Vulnerable to Environmental Toxins

There are two periods in our life when our brain is the most vulnerable to environmental toxins – during fetal development and in older age. There are major concerns about exposures early in life that don’t manifest neurological conditions until later in life. There have been an increased number of studies over the past ten years that have looked at low-level lead exposures on adults’ cognitive abilities later in life. There was a study done with 466 older participants from the VA Normative Aging Study who were environmentally exposed to lead. Lead accumulates in our bones but can be mobilized over time as part of the aging process. “The study demonstrated that higher bone lead levels were associated with steeper declines in these men’s cognitive ability over several years of follow-up.” (Grossman, Sept. 2014) There was a subset of this study group where low-level of lead exposure combined with chronic stress are associated with a decrease in cognitive ability. Think back to our younger days: there was lead in gasoline, lead in paint, lead pipes that made up our plumbing systems. These study results are unnerving.

Effects of Metals, Pesticides, and Solvents on the Brain

Lead and mercury have been associated with liver disease. The adverse neurological health effects of this duo are a type of neuronal plaque associated with Alzheimer’s disease. Let’s continue on with our metals, pesticides, and solvents effects on the brain. There is evidence connecting certain metals (lead, manganese), pesticides (paraquel, maneb), and solvents (toluene, trichloroethylene) with neurological symptoms characteristic of Parkinson’s disease. Here is a breakdown of common neurodegenerative diseases and their causes:

· Alzheimer’s disease: the most common neurodegenerative disease, afflicting more than 5 million Americans. Alzheimer’s is perceived to be an aging disease with most diagnosis coming to those 65 and over. Metals, including aluminum, zinc, copper, and lead have been linked to inducing plaques causing neurodegeneration to the brain, which serves as our metal ion concentration regulator.

· Parkinson’s disease: the second most common neurodegenerative disease. About 1 million Americans have Parkinson’s disease. Risk factors for PD include exposures to pesticides (often seen in rural residents who consume well water), metals, and solvents. Miners and welders are at risk for PD by accumulating large amounts of manganese in the body.

· Amyotrophic Lateral Sclerosis (ALS): characterized by degeneration of lower motor neurons in the brainstem and ventral horn of the spinal cord. More than 30,000 Americans have ALS. The links to environmental exposure are still not well established, but some scientists contend that exposures to lead, mercury, and pesticides are risk factors.

(Aging Exchange, 2014)

Solvent Exposure and Neurological Conditions

There is substantial evidence to point to the link between solvent exposures and neurological conditions. These conditions include cognitive impairments, neuropathy, and pseudodementia (temporary neurologic dysfunction producing symptoms similar to dementia). Our hormonal system is especially vulnerable to subtle exposures to chemicals. Thyroid hormones are essential for healthy brain development and function and in later life these hormones do different things at different periods of the life cycle. PCBs (polychlorinated biphenyls), dioxins, and pesticides can all interfere with human hormones and promote diabetes and obesity. This increases hypertension (HBP) and CVD (cardiovascular disease) which in turn can lead to neurodegenerative effects by reducing oxygen to the brain cells. When chemicals interfere with human hormones, they decrease the potential for exercise which is crucial to maintain strong physical and cognitive abilities.

Here some ideas on reducing your everyday exposure to environmental toxins:

· Choose foods with limited pesticides

· Opt from renovation materials that are less dangerous for the environment

· Use batteries without mercury (cell button batteries contain mercury)

Knowledge is power when you use that knowledge. Pay attention to what you eat, what products you use on your landscaping, and do your best to do whatever you can to control air pollution. Everyone is impacted by environmental influences. We will protect ourselves and others when we work for safe environmental policies.


Bakalar,N. (June 22, 2015). Pollution may age the brain. The New York Times. Retrieved from

Environmental Impact on Brain Aging: Scientist Studies How Toxins Accelerate Neurodegeneration. (Spring 2014). Aging Exchange Tracking the Way We Age: CALC Center on Aging and the Life Course.

Grossman, E. (September, 2014). Time after time: environmental influences on the aging brain. Environmental Health Perspectives; 122(9). DOI:10.1289/ehp.122-A238.

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