This study aims to investigate breast milk composition and dietary habits of Chinese lactating mothers. Further understanding of the composition of human milk will help to understand the nutritional needs of mothers and their infants in their early phase of life which eventually will help to support breastfeeding.

Inclusion Criteria:

• Generally healthy mothers who give birth to a healthy term infant (37-42 weeks) whose birth weight is >10 and <90 percentiles gestational birth weight chart.
• Aged 20 - 40 years.
• Mothers who intend to exclusively breastfeed the infant for more than 6 weeks.
• Chinese ethnicity, including both parents.
• Mothers who sign the informed consent form in writing.

Exclusion Criteria:

Mothers:

• Participation in any other studies involving investigational or marketed products concomitantly or two weeks prior to entry into the study.
• Difficult to follow up and/or locate (e.g. known transfer to other hospitals, residing outside Shanghai, plan to move out of Shanghai).
• Current smoker or having smoked during the pregnancy.
• Having consumed alcoholic drinks during pregnancy or lactation.
• Illegal drug abuser: cannabinoids (marijuana, hashish), stimulants (cocaine, amphetamine, methamphetamine), opioid (heroin, opium).
• Acute infection disease or neoplastic disease or any kind of weakening or debilitating conditions (no history of positive HBV, HCV or HIV serological test at any time during the pregnancy).
• Use of drug or pharmacologically active substances (e.g. herbal products, traditional medicine) to treat a particular disease or medical condition from the beginning of lactation ( those who consume herbal/traditional medicine for maintaining or improving well-being will still be included).
• Presence of mastitis, fungal infections of the nipple or areola; reactivation of herpes simplex (HSV) or varicella zoster infection in the mammary or thoracic region at the time of enrolment.
• Presence of endocrinology diseases, particularly diabetes mellitus and gestational diabetes.
• Presence of obesity (pre-pregnancy BMI > 28).
• Presence of chronic diseases such as cardiovascular, renal, respiratory and hepatic diseases.
• Presence of psychosis and severe post-partum depression.
• Presence of autoimmune disease such as systemic lupus erythematosus, systemic scleroderma, ulcerative colitis, Crohn's disease, celiac disease.
• Women whose health condition, according to the investigator's judgement, could interfere with the study conduct and assessment.
• Mothers who have given birth to twins or multiples or infant conceived with Assisted Reproductive Technology (ART).
• Elimination diet due to chronic allergic diseases or vegan.
• Incapability of subject to comply with study protocol or investigator's uncertainty about the willingness or ability of the mothers to understand and comply with the protocol requirements.

Infants:

• Any congenital abnormality, chromosomal disorder or severe disease which could interfere with the study conduct and assessment.

General health lactating mothers