Recently, there has been an increasing interest in health-promoting products which are also natural and safe for consumption because the consumer market has been searching for a healthy lifestyle. This global market trend has driven the food industry to invest in developing innovative products containing bioactive components. Flavonoids are a group of phenolic compounds of low molecular weight, consisting of 15 carbon atoms. Their alterations in the heterocyclic ring’s substitution pattern generate six subclasses: flavonols, flavanols, flavones, flavanones, isoflavones and anthocyanins. Also, different studies have reported that diets rich in flavonoids provide numerous benefits associated with health-promoting effects by reducing the risk of development of chronic diseases such as cardiovascular diseases, diabetes type II and some types of cancers. These effects have been related to their biological properties which also include other activities such as colorant effects (e.g., anthocyanins), transforming them into potential food additives with desirable capacities. Therefore, this review aims to revise the classes of flavonoids and their main biological properties as well as the most used extraction techniques applied for obtaining these compounds, their bioavailability and the application to formulate new natural food additives.