Since the last century, fortified and enriched foods are products whose original composition has been modified–through addition of essential nutrients–to satisfy specific population needs. For the fortification of foods to have a positive impact on nutritional status, the micronutrients added must be well absorbed and utilized by the organism (bioavailability). Diverse factors affect bioavailability, such as the nutritional status of individuals, the presence in the diet of substances which facilitate or inhibit its absorption, interactions among micronutrients, illnesses, and chemical characteristics of the compound used for fortification. In countries such as Chile, Venezuela and Mexico, important effects have been demonstrated in reducing iron deficiency anaemia in children under 5 years of age. In less than a decade, the salt iodization programme has also proven its effectiveness. Other programmes have fortified foods with Zn, vitamin A and folic acid, which are deficient in infants and children of many populations. In summary, food fortification is a low-cost, relatively simple strategy that may reach a wide range of people, and contribute to reducing the high prevalence of micronutrient deficiencies affecting children, especially in poor countries. The costs due to losses of human capital and their repercussions on health and future development are very high. Building links among academic researchers, politicians, food manufacturers and consumers is essential in order for food fortification to be efficacious and effective, and therefore should be considered as part of an integral strategy to combat micronutrient deficiencies.