Antioxidants and Oxidative Stress as Foe and Friends in Prevention of Cancer

Cancer has become a major public health problem and is one of the leading causes of death among humans worldwide. It is characterized by the abnormal proliferation of cells due to failed normal regulatory mechanisms. Oxidative stress plays a crucial role in the pathology of many cancers and is characterized by an imbalance between the production and removal of reactive oxygen species (ROS). Under normal physiological conditions, the intracellular levels of ROS are steadily maintained to prevent cell damage, and detoxification of ROS is facilitated by various non-enzymatic and enzymatic antioxidants. These antioxidants have a widespread application in the prevention of cancer, as many endogenous and exogenous antioxidants can prevent and repair damage caused by disrupted redox status of cells during carcinogenesis. Our body can produce some of the antioxidants, but to obtain the rest of the antioxidants, it relies on external sources, primarily the diet of an individual. Also, there are certain health issues reported with the long-term usage of synthetic antioxidants. Therefore, nowadays, many nutritionists and dieticians suggest consuming food and natural products that are either rich sources of antioxidants or are supplemented with various nature-based antioxidants. This chapter seeks to explain the role of ROS in oncogenesis, understand the dynamics between oxidative damage and the antioxidants, types of antioxidants, natural sources of antioxidants, mode of action of antioxidants and the role of antioxidants in cancer prevention and treatment along with their disputable effects in cancer therapy.