“Cow’s milk contains very little iron and is extremely filling. A child who fills up on milk may have little appetite left for foods such as meat, fish, eggs, beans, lentils, green vegetables and fortified cereals.
Article source: https://www.huffingtonpost.co.uk/entry/cows-milk-low-iron-toddlers-explained_uk_6a7c8ac7e4b0ecad6d3db168