[Importance of nutrition during pregnancy. Impact on the composition of breast milk].

The consumption of a healthy diet is essential during the preconception period, pregnancy and lactation to guarantee maternal-fetal and newborn health. It is important to take into account when configuring the maternal diet that inadequate intakes of vitamins and minerals, as well as a high consumption of foods or beverages with refined sugar increase the incidence of low birth weight infants, while the adequate consumption of micronutrients and carbohydrates (mainly integral) can decrease it. Prenatal consumption of fish is also associated with less intrauterine growth retardation. Maternal nutritional deficits that lead to intrauterine growth retardation can alter the expression of some genes, causing abnormal programming in organ and tissue development. In response, the fetus adapts to this situation of scarcity and may have difficulties adapting to an abundant consumption of food after birth, increasing its propensity to suffer from cardiovascular and metabolic diseases in adult life. After delivery, the nutrition of the infant must be guaranteed through breast milk. There is a relationship between the nutritional status of the mother and the composition of the mother's milk and, therefore, in the supply of nutrients to the infant, which may condition their health. Despite the great importance of an adequate maternal nutritional state, serum deficiencies in vitamins A, E, C, B2, B1, calcium and zinc are observed in pregnant mothers and breast milk, being important to identify and prevent these imbalances before conception and during pregnancy and lactation.