A variety of formulas are available for infants younger than 12 months of age if breast milk is not used. These formulas vary in caloric density, nutrient composition and ingredients, digestibility, taste, and cost.

Guidelines for infant formulas and standards for normal infant feeding based on human breast milk have been provided by the American Academy of Pediatrics (AAP).

Specific types of formulas include:

• Standard milk-based formulas
• Soy protein formulas
• Formulas for premature infants
• Formulas for infants with metabolism problems

The standard milk-based formulas contain heat-treated cow's milk protein (at reduced concentrations), lactose and minerals from cow's milk, vegetable oils, minerals and vitamins. The amount of each nutrient is set to standards based on levels in breastmilk.

The AAP recommends iron-fortified formulas for all infants. Standard formulas contain 20 Kcal/ounce and .45 grams of protein/ounce. Additional vitamin supplements are not usually recommended.

Consuming more than the daily requirement of vitamins is unnecessary and potentially harmful. Depending on the water supply, pediatricians may prescribe a fluoride supplement to help the infant develop strong teeth and bones.

Management of infants with metabolic problems should be discussed with an experienced dietitian and physician. Formula choices may be affected by the condition of the infants' gastrointestinal track and metabolism.