Air Pollution and Brain Inflammation

Car exhaust and other forms of big-city pollution seem to lower IQ.Like most scientific tales, this one is partly a detective thriller. Mexico City-based pediatric neurologist, Lillian Calderon-Garciduenas, had a hunch that the megacity's notorious pollution was harming children. She was worried about widespread evidence of childhood lung and heart disease. Perhaps most troubling: something seemed to be ravaging their minds. For children enrolled in her studies, Calderon-Garciduenas was documenting cognitive impairments in memory, problem solving and judgment, and deficiencies in their sense of smell compared with age-matched children from a cleaner city 120 kilometers away. In a move Sherlock Holmes would appreciate, Calderon-Garciduenas conducted autposies of seemingly healthy Mexico City children who had died in auto accidents or from other traumatic events, and she found widespread evidence of deposits of proteins that serve as hallmarks of Alzheimer's and Parkinson's diseases.

Dr. Merrell's Tip: People living in urban environments can help their bodies process pollutants by eating a diet rich in antioxidants and anti-inflammatory substances (found in fruits, vegetablesc, fish and olive oils, dark chocolate and green tea.) Also, reduce exposure to airborne pollutants by using HEPA air filters in the bedroom (which only work when windows are kept closed.) 

Fast-forward through several years of global scientific research, and a picture begins to emerge of pollutions' effects on the brain. Increasingly, studies point to inflammation-provoking nanopollutants as a potential source of nerve cell damage. In studies of Boston 10-year-olds, researchers have found those living in areas with the highest average airborne concentrations of soot, a pollutant primarily associated with traffic, had lower IQs and lower scores on memory tests--comparable to IQ point drops identified in kids whose mothers had smoked during pregnancy.

The nose is crucial to understanding the problem. Research has identified the nasal passage as a front door that allows micro-particles of pollution to march into the brain. If the nasal tissues are inflammed, say, from allergies or sinusitis, the uptake of soot may be maginfiied.

There are mitigating factors. Not all pollution is equal. Mexico City air contains the metal manganese, which has been shown to migrate into the brain through the nose with unusual ease. And manganese is perhaps one of the most neuro-toxic metals. Genetic pre-disposition also play a roll. Calderon-Garciduenas has found that children with a particular gene variant (known as APOE-4) that predisposes them to Alzheimer's exhibit the most inflammation.

There are potential solutions. Short of moving and hoping for governments to clean up the air, the best bet is to eat an anti-inflammatory diet, rich in brightly colored fruits and vegetables and augmented with omega-3 fatty acids and specific anti-inflammatory foods like green tea, dark chocolate and the spice turmeric, which has been shown specifically to reduce the formation of amyloid-beta plaque. Calderon-Garciduenas has recently been feeding dark chocolate rich in polyphenols, a class of natural antioxidants, to inflammation-ravaged lab-mice. She has not published her study yet, but word is her prelimanary data shows great promise.

For a more detailed look at Calderon-Garciduenas research, see Destination Brain, ScienceNews, May 22.