Lysine Requirements During Lactation

Inclusion Criteria: * Healthy * Female * 20-40 years * Had a singleton pregnancy and is breastfeeding a single child. * Exclusively breastfeeding an infant 3 - 4 months of age OR complimentary. feeding an infant 9-10 months of age. Exclusion Criteria: * Participants not in good health or have a history of metabolic, cardiovascular, neurological, genetic, endocrine, immune, or physical mobility disorders. * Participants that had major pregnancy or delivery complications (e.g., preeclampsia/ eclampsia, placenta previa, postpartum haemorrhage, neonatal intensive care, gestational diabetes). * Participants with substance dependence issues (e.g., nicotine, alcohol, marijuana, illicit drugs). * Participants that have had breast surgery that may impact lactation, lactogenesis or breastfeeding. * Participants that use medications that affect lactation (e.g. estrogenic birth control, anti-dopaminergic drugs, Methyldopa) or other continuous prescription medication. * Participants with a pre-pregnancy BMI below 18 kg/m² or above 28 kg/m². * Participants who are below 20 years of age or greater than 40 years of age. * Infants' weight and length are under 3rd or above the 97th percentile, using the World Health Organization (WHO) percentile growth chart. * Infants born before 38 weeks or after 42 weeks of gestation. * Infants who use infant formula milk. * Infants with known metabolic, cardiovascular, neurological, genetic, endocrine, immune, or physical mobility disorders.