How Free Radicals Damage the Cell

by Dr Gary I Weinberger

In my previous blogs I tried to define and simplify the concept of antioxidants. I will now focus on how these antioxidants ROS (reactive oxygen species) and RNS (reactive nitrogen species) act to damage the cell. These reactive species exert their damage at the cellular level either by damaging the cell at the level of the cell’s nucleus or at the level of the main body of the cell or cytoplasm.

DNA DAMAGE- The nucleus is the “brain center” of the cell and is the area where the cell stores its genetic material. Damage to the nucleus can significantly alter the structure and function of the entire cell. The environmental stresses that are responsible for damage to the nucleus are oxidation, methylation, depurination, and deamination. Nitric oxide, a normal chemical found within the cell can undergo chemical changes when exposed to these environmental contaminants and form by-products like NO2, ONOO-, N2O3, and HNO2. These substances are known to cause abnormal alteration in the cell’s genetic material the result of which is the formation of various forms of cancer. By protecting the nuclear material from damage caused by environmental ROS and RNS through the use of antioxidants, either topically with antioxidant creams like creams containing lycopene or orally through supplements rich in antioxidants, it is hoped that the incidence of certain cancers can be reduced.

MITOCHONDRIAL DAMAGE- If the nucleus is the brain of the cell than the mitochondria is the “power supply” and “regulator” of the cell’s activity. The mitochondria is a cellular organelle (microscopic organ like the heart) found within the cell body or cytoplasm of the cell. This organelle is important for many of the normal functions of the cell and damage to this structure is important in several human diseases as well as the aging process. It is believed that environmental and dietary free radicals damage the cell at the level of the mitochondria and results in aging. It is postulated that foods rich in antioxidants that inhibit free radicals formed by high caloric diets may increase life expectancy by reducing the cellular damage caused by the ROS and RNS. It is thought that the mitochondria are the most important source of intra-cellular free radicals. It seems very likely that ROS free radicals are produced by the mitochondria which in turn results in damage to the mitochondrial DNA. This process may result in alterations of the mitochondrial genetic material and could play a role in certain diseases and cancers. It is believed that oral antioxidant supplements can reach protective levels in various organs like lungs, heart and prostate, however, newer studies are showing that sufficient antioxidant levels cannot be achieved in the skin through oral supplementation. It is for this reason that creams containing antioxidants like, lycopene and Vit E, appear to be the best way to protect the skin from the oxidative damage of environmental stresses like air pollution and the suns UV rays.