A review of the destructive effects of free radicals on various diseases

The human body needs oxidants (free radicals) and antioxidants for normal metabolism, signal transduction, and regulation of cellular activity. Free radicals can be beneficial or harmful to the body. A balance between free radicals and antioxidants is essential for the body's physiological function, But sometimes the human antioxidant defense system in is unable to develop resistance to free radicals. Eventually the balance between free radicals and internal antioxidants is lost; This imbalance is called oxidative stress. The purpose of this study is to review free radicals and express the role of oxidative stress in causing human diseases. The results indicate that oxidative stress due to the imbalance of free radicals and antioxidants causes cardiovascular disease, neurosis, stroke, liver disease, reproduction, diabetes, autism, cancer, aging and so on. There are many factors involved in causing oxidative stress that by staying away from these factors, humans can play an important role in reducing the effects of free radicals.