Breast milk contains millions of cells. What are these cells and what do they reveal?

Toni Harman
6 min readAug 17, 2022

Human mammary glands can produce more than a litre of breast milk a day, but studying how mammary glands actually produce the milk is tricky. Now a new large-scale, high-resolution study provides some fascinating insights into milk production through analysis of the cells contained in breast milk. The study reveals milk-producing cells change over time in breastfeeding mothers.

Breast milk contains millions of cells. What are these cells and what do they reveal? Nyquist SK et al., Proc Natl Acad Sci USA (2022) http://microbiomecourses.com

Breast milk is a dynamic fluid that is incredibly complex.

Amazing breast milk fact #1

Human mammary glands can produce more than a litre of milk a day, and this can continue for years after birth.

Amazing breast milk fact #2

Amongst a long list of complex components, human milk contains millions of cells.

Many of these cells relate to milk production.

These cells are thought to enter the milk through the process of breastfeeding.

Studying mammary gland cells in mothers is tricky as the tissue can’t be biopsied, and can’t be accessed during breastfeeding.

So by analysing the cells found in breast milk, this provides a non-invasive way to study lactational cells.

--

--

Toni Harman

I help parents and health professionals better understand the science of pregnancy, birth, breastfeeding and the microbiome. https://linktr.ee/toniharman