It is recommended that babies transition off bottles and formula at 1 year old. Why, then is it recommended to still continue breastfeeding and breast milk until 2+ years? There are several things at play: oral development and nutrition.
Breast and bottle feeding work completely different. As a baby breastfeeds, the human breast/nipple changes shape in baby’s mouth. Breastfeeding requires baby to coordinate their orofacial muscles to form a vacuum to extract milk from the breast. The back of the tongue firmly rests on the palate, which allows the tongue to shape the upper jaw, and naturally expand the palate (widening the upper jaw so the tongue fits in it perfectly). Once milk is released, the tip of the tongue pushes the breast against the front of the palate, stimulating the forward development of the front part of the upper jaw and midface. As the lower jaw moves back and forth, it stimulates forward growth of the lower jaw too. Forward growth of the jaws and face help in forming the airway. The firm nipple of a bottle does not change shape in baby’s mouth, and some bottles work on compression only where the vacuum does not need to be as strong. Cup feeding uses muscles more similarly to breastfeeding than a bottle. When we transition a baby to an open cup, we are promoting a more mature swallow and oral motor pattern. You can transition a baby to an open cup at 6 months, but should definitely try to transition off the bottle between 12-18 months for optimal facial and swallowing development.
Nutritionally human milk is constantly changing based on the age of your little one. It’s hormones, stem cells, and antibodies are tailored to meet the needs of a growing toddler. Human milk is phenomenal for development and immunity. Infant formulas are designed to meet the nutritional needs of a child on an exclusive milk diet prior to eating table food. They are designed to grow a baby from 0-12 months based on what we know those babies need nutritionally. Once a toddler moves to eating table foods, they can get all of their nutrients and calories from a balanced diet.