Researchers now know one way in which stress may cause disease. A stressful life mass-produces free radicals. The pollutants produced by modern technologies often generate free radicals in the body. The food most of us buy contains farm chemicals, including fertilizers and pesticides, that produce free radicals when we ingest them. Processed foods frequently contain high levels of lipid peroxides, which produce free radicals that damage the cardiovascular system.
Air pollution has similar effects.
Exposure to sunlight generates free radicals that age the skin, causing roughness and wrinkles. If the exposure is prolonged, skin cancer may result. SOD and another important antioxidant enzyme set, the glutathione system, work within the cell. By contrast, circulating biochemicals such as uric acid and ceruloplasmin react with free radicals in the intercellular spaces and bloodstream. The substances that plants create to fight free radicals can help the human body do the same thing.