The Lungs 

Our lungs have constant exposure to the environment in which we live.  Given their critical role in providing oxygen to cells throughout the body as well as expelling carbon dioxide, the lungs are intimately involved with agents in our environment. 

The lungs emphasize the importance of air quality in our lives, but they also move us toward greater health by playing an important part in immune and detoxification functions.  Complex and under-appreciated, they both serve as barriers against toxins entering the bodies, and respond to those which manage to get past safeguards. 

The lungs aid the body's detoxification response by expelling metabolic wastes that build up in basic metabolic functions. The most widely recognized is carbon dioxide, which is removed from the blood and expelled through the breath.  In addition, the lungs, like the liver, have the ability to transform toxins into water-soluble forms, that can be processed by other systems.  According to Jacqueline Krohl, M.D., a coauthor of The Whole Way to Natural Detoxification: The Complete Guide to Clearing Your Body of Toxins, the lungs can also metabolize toxins.  "The lungs contain enzymes from the mixed function oxidase family," she writes, "enabling them to metabolize drugs and xenobiotics to more-water soluble chemicals, which can then be excreted by the kidneys." (Pg. 30)

The lungs have three basic methods of protecting themselves from impurities in our air – epithelial barriers, enzyme systems and immune responses.   Their epithelial barriers are groups of macrophanges, i.e. immune cells, that can identify invasive agents and attack them.  Together with lymphocytes they destroy foreign substances.  In one enzyme system, destructive inflammatory enzymes known as proteases respond to inhaled particles.  Proteases, in turn, trigger the release of anti-proteases, which protect the delicate air sacs of the lungs.  Smoking destroys the balance between the protease and the anti-protease enzymes.  Antioxidant enzymes are also released to counteract free radicals from the environment.  Finally, immunoglobulins, including IgA, IgG and IgE, all patrol the respiratory tract, defending it from microbes and tumor cells.