Therefore, those formulas without lactose will use other sources of carbohydrates, such as sucrose and glucose, dextrins, and natural and modified starches. Lactose is not only a good source of energy, it also aids in the absorption of the minerals magnesium, calcium, zinc and iron.[65] Nucleotides Nucleotides are compounds found naturally in human breast milk. They are involved in critical metabolic processes, such as energy metabolism and enzymatic reactions.