Pollution and the Brain

Here is something that should get everyone’s attention: Recent studies found that damage in the brain from exposure to air pollution begins during childhood.

MRI scans have shown lesions in the prefrontal cortex, the most complex thinking area of the brain, in children exposed to heavy pollution in cities. More importantly, researchers have demonstrated impaired thinking and learning ability in these children — a result that was also reported in animals exposed to heavy concentrations of pollution particles.

Multiple sclerosis, stroke, and Parkinson’s disease are all increased in people exposed to these pollution particles, especially the ultrafine particles. A number of studies have shown that the ultrafine nanoparticles cause much greater inflammation and microglial activation — and hence immunoexcitotoxicity — than larger particles. This is primarily because these extremely small particles have a much larger reactive surface per volume than larger particles. They can also easily penetrate these sensitive areas:
• Lungs
• Skin
• Olfactory tract
• Brain
In addition, studies show that ultrafine particles easily penetrate cells and compartments within cells, such as the mitochondria. This makes the particles dramatically more toxic. It is also known that certain people are genetically at a greater risk from these metals than others.

For example, people who have the APOE4 allele (a particular DNA sequence associated with Alzheimer’s risk) are at much greater risk than those who do not have those genes. Also, those who have chronic illnesses, pre-existing brain disorders (including depression and other psychiatric disorders), and poor detoxification ability are at greater risk.

Studies involving experiments on both animals and humans have demonstrated that systemic inflammation (in the body, excluding the brain) can cause the brain to become inflamed and ultimately lead to degeneration of the brain.

For example, getting the flu makes you feel bad, makes you have trouble sleeping, impairs your memory, and makes you irritable. All of this happens because your brain is temporarily inflamed. With these particles, especially nanosized metal particles, the brain inflammation can go on for years, even a lifetime.

Most of these harmful particles will enter the brain by way of the olfactory nerves (in the nose) and the trigeminal nerves (in the lining of the mouth). From the olfactory nerves, the particles move toward the parts of the brain most seriously affected by Alzheimer’s disease — the entorhinal cortex and the hippocampus.

Once inside the brain, the particles trigger intense activation of the brain’s immune cells, the microglia, which release powerful inflammatory cytokines and excitotoxins that destroy brain-cell connections (synapses and dendrites).

These tiny particles can also be coated with other toxins, which are then carried into the brain like a Trojan horse. We see this with one major pollutant in cities: diesel fuel particles from exhaust fumes. Autopsy studies of people living in heavily polluted cities have demonstrated microglial activation and brain inflammation. Find more details on how you can keep your brain healthy, read my report "Save Your Brain."

When I see people jogging or riding their bikes along a heavily traveled street, I realize that these health enthusiasts are actually destroying their health, completely unaware of the danger.

When you exercise, your body is at its most vulnerable. This is because your tissues, including the brain, are low on oxygen, and free radicals are generated by the exercise and you may have low energy levels. Most of these pollution particles damage tissue through inflammation and high free-radical generation.

So, how can you protect yourself? Avoidance is always best, but often is not practical. Try not to spend too much time close to the side of a busy street, and never run or exercise by a heavily traveled roadway. People should restrict walking, jogging, and bike riding to isolated trails, away from the city’s pollution.