As the sole source of nutrition for babies, infant formulas must provide energy, fat, protein, carbohydrate, vitamins, minerals and trace elements. The level of each nutrient provided is specified by law. The proportions of energy supplied by protein, fat and carbohydrate in infant formulas are similar to those in mature breastmilk.

Nutrient	Comment
Fat	Fat in formula is based on a blend of dairy or vegetable fat selected for their appropriate levels of unsaturated fat and other absorption characteristics
Carbohydrate	Mature breastmilk contains about 7% carbohydrate which is present as lactose. In infant formulas the carbohydrate level of cows' milk is adjusted to match that of breastmilk. The milk sugar, lactose and sometimes other approved carbohydrate sources are used for this purpose.
Protein	The protein source for infant formulas is either cows' milk or soya. Whatever the source the amino acid content is adjusted to approximate that of breastmilk and to meet the needs of the rapidly growing infant.
Vitamins and minerals	Vitamins, minerals and trace elements are added to infant formulas during manufacture to meet the infant's nutritional needs and to comply with legal requirements.
Other	Infant formulas may also contain other components that are found naturally in breastmilk, such as long chain polyunsaturated fatty acids (for brain and membrane development), oligosaccharides (to aid digestion and immunity), or nucleotides (for healthy growth and development and to help the immune system).