Scientific investigations have found a link between food and health, examining the impact of individual food elements on bodily systems. The phrase "functional food" originated in Japan and refers to foods with distinct positive properties. This presents an overview of functional components found in diverse foods, as well as their physiological effects and advantages. And also the people affected during the World War II without getting proper nutrition and died because of various diseases. The evidence showing the decrease in the deaths and increase on health benefits after the intake of functional foods is shown. Finally, the benefits of using functional foods in the future.