Global studies map how human milk varies and stays regulated
Two international studies led by the University of Manitoba examined human milk as a complex biological system rather than just a nutrient mixture. They found that some milk components change with maternal nutritional supplementation, while others remain tightly regulated or reflect the biology of the lactating breast and infant growth. The research, published in Science, drew on more than 1,000 mother-infant pairs across Canada, Burkina Faso, Tanzania, and Pakistan.
The International Milk Composition Consortium, coordinated by the University of Manitoba, brought together over 20 scientists from 13 organizations spanning six countries and four continents. Its two Science papers examined milk from more than 1,000 mother-infant pairs in Canada, Burkina Faso, Tanzania, and Pakistan, analyzing nearly 2,000 samples for over 25,000 compounds.
One study found that giving mothers nutritional supplements while breastfeeding changed certain milk components, including B vitamins, selenium, and triglyceride profiles, while other components stayed unchanged. The other linked milk patterns to mammary gland processes, including milk production and release, barrier function and tissue restructuring, and immune responses and repair.
These findings may inform future maternal nutrition guidance and supplement design, potentially benefiting breastfed infants, especially where undernutrition is common. Families, clinicians, and public health programs could use milk-composition insights to better understand infant growth and mammary function. However, because the work maps associations and responses across diverse populations, practical applications may take time and require validation before changing care.