Infant milk formula varies in the kind of protein and sugar they contain. Regular iron-fortified formulas are made with cow's milk protein and lactose. Most of the toddlers who are not consuming mother's milk must be given cow's milk-based iron-toned formula. L-Zero, one of the most amazing lactose-free formula supplements is e prepared using casein, MCT, and nucleotides. This lactose-free formula is easy to tolerate and digest for babies with protein sensitivities.