Reactive oxygen species as initiators of oxidative stress account for LDL and DNA oxidative changes that are respectively associated with the development of pathological conditions such as atherosclerosis and carcinogenesis. This review paper first focuses on specific bio-indicators used to monitor these harmful oxidative stress conditions and develop health strategies against the associated human diseases. Subsequently, it provides an overview of the most recent available literature on the protective role that certain antioxidant vitamins (vitamin C, vitamin E and provitamin A compounds) have been reported to exert against the biochemical oxidative processes that govern the initiation of these specific human diseases.