Human Milk Nutrients and Infants' Health Outcomes in South China

Inclusion Criteria: * age 4-5 years * healthy children * breastfeeding between 0 to 400 days of age * human milk components in human milk being determined * sign informed consent Exclusion Criteria: * children with severe chronic diseases, such as tumor, severe digestive diseases, kidney diseases * gestational diabetes, hypertension and other metabolic diseases * children with mental system diseases * children with congenital and genetic diseases * children with infectious diseases, eg, upper respiratory tract infection or diarrhea * antibiotic or other drugs influencing intestinal flora being taken within 45 days * Withdraw withdraw informed consent serious violation of the scheme no longer meet the research criteria because of health factors or accidents