Considerations for the effects of antioxidant phytochemicals on human health

Phytochemicals in fruits, vegetables, cereals, and nuts, advertised as “antioxidants”, combat undesirable effects of reactive oxygen species (ROS) in the body. These undesirable effects include cancer, cardiovascular diseases, and neurodegenerative disorders. Although ROS were initially considered to be primarily damaging agents, ROS have been discovered to play a role in signaling immune and other physiological responses in recent years. Several studies have demonstrated that ROS act as essential signaling molecules to promote metabolic health. Therefore, the overall advantage of the interference of ROS signals by antioxidants could be questionable. Future research is required to understand the implications of the application of phytochemicals in functional foods and supplements for health benefits on ROS levels in the body. This study describes the new roles of ROS and hormesis of various phytochemicals to provide a possible research guideline to food and nutrition scientists.