The purpose of this study is to look at the function of infant formula components to optimize the nutritional content and functionality of a marketed routine infant formula.

Inclusion Criteria:

• 10-18 days of age
• 37-42 weeks gestation
• birth weight 2500 g or more
• consuming one source of nutrition

Exclusion Criteria:

• metabolic or chronic disease
• acute infection
• feeding difficulties
• consumed complementary foods or donor milk
• steroid use

formula-fed and breastfed infants