When we talk about complementary feeding we are referring to solid, semi-solid or liquid foods containing nutrients and energy that are given to infants in addition to human milk or infant formula. The introduction of complementary foods is considered a critical step in the infant’s diet as they impact growth and have long-term health consequences.
Complementary feeding in infants
Human milk provides an unparalleled source of nutrition for infants in the early stages of life. Its composition is dynamic and evolves over time to adapt to the nutritional needs of infants. In particular, the protein concentration follows a temporal pattern and decreases with the progressive stages of lactation.
However, in formula-fed infants, protein intake is higher than in breast-fed infants. If there is also a high protein intake during the complementary feeding period, there is a greater risk of developing obesity in the future. Therefore, it is currently recommended to use formulas with an optimized protein profile in quality and quantity and complementary feeding that does not increase the overall protein intake to promote adequate growth and healthy development of infants.
The two key reasons for initiating complementary feeding are:
– Breastfeeding alone is insufficient to meet the nutritional needs of the developing infant.
– It is important to introduce solid foods with new tastes and textures to develop healthy eating habits.
The World Health Organization (WHO) and the American Academy of Pediatrics recommend exclusive breastfeeding for the first six months of age, with the introduction of complementary feeding thereafter. The European Society for Pediatric Gastroenterology, Hepatology and Nutrition recommends its introduction between 4 and 6 months of age.
The common practice in pediatrics is to introduce iron-fortified cereals, followed by fruits and vegetables, and then meat. New “single-ingredient” foods should be introduced each time and no new foods should be introduced for at least 3 to 5 days. Between 7 and 8 months of age, infants should consume foods from all food groups. Whole cow’s milk should not be introduced until 12 months of age.
Parents should be aware that early introduction of complementary feeding, below 4 months of age, and excess protein intake has been linked to the development of overweight, obesity, diabetes mellitus, cardiovascular disease, atopic disease, allergies and celiac disease. And also that late introduction of complementary foods can lead to inadequate nutritional status and compromise the infant’s immune development.
Complementary feeding in preterm infants
Preterm infants have different nutritional requirements from full-term infants, especially for energy, protein, long-chain polyunsaturated fatty acids, iron, zinc, calcium and selenium. Optimal nutritional intake is very important in these infants from birth to infancy to achieve adequate growth, especially cephalic growth that may have an impact on long-term neurodevelopmental evolution.
Therefore, the introduction of complementary feeding in preterm infants is very important to avoid growth retardation and important nutritional deficiencies. The appropriate timing of its introduction will depend more on their level of gross motor development, especially cephalic control, than on chronological age.