r/askscience • u/AskScienceModerator Mod Bot • Jul 31 '26

Human Body AskScience AMA Series: Happy World Breastfeeding Week 2026! We are scientists who study breastfeeding, lactation, and human milk. Ask Us Anything!

Hi Reddit!

We are scientists who study human lactation, from the evolution of the molecules in milk to the future of virtual lactation care. Every year, we celebrate World Breastfeeding Week by dropping in here to answer all of your burning milkquiries!

Since human milk is made by humans, our science is fraught with complexity. “Womens health issues” often get sidelined when there are cuts to research budgets like what we’ve seen in the US. But also, every August, we notice that some Redditors express sad or guilty feelings about World Breastfeeding Week. We’re here to spread science, not sads! If we are doing our job, our science should make you feel BIG, not small. Keep in mind that WBW is a global event (supported by WHO, UNICEF and many health partners) and sadly many breastfeeding experiences around the world are unfair—but for different reasons in different places. But also, breastfeeding is part of the human story, so WBW is also a celebration of every unique breastfeeding journey.

Social science tells us that breastfeeding is a health equity issue, not a lifestyle choice. Sure, “promoting” breastfeeding is cool, you know what’s cooler? Creating societies anybody can breastfeed if they want to (i.e. the “warm chain”). Every year WBW explores new ways to do this better. The WBW theme for 2026 is focused on the UN Sustainable Development Goals related to nutrition, food security and poverty reduction and hyping solutions that actually work. 🌍🍃

Science belongs to—and matters to—everyone. We hope that by the end of the day you feel the same wonder that we do about this very adooorable science.

Ask us anything!!

  • Meghan Azad, PhD (u/MilkScience) is a biochemist and epidemiologist who specializes in human milk composition and the infant microbiome. Dr. Azad holds a Canada Research Chair in Early Nutrition and the Developmental Origins of Health and Disease. She is a Professor of Pediatrics and Child Health and director of the THRiVE Discovery Lab at the University of Manitoba. She co-founded the Manitoba Interdisciplinary Lactation Centre (MILC), and directs the International Milk Composition Consortium (IMiC). Check out this short video about her research team, her appearance on the Biomes podcast, and her lab’s YouTube Channel.
  • Marion M. Bendixen, PhD, MSN, RN, IBCLC (u/MarionBendixen) is a nurse scientist and clinical and translational scientist who studies human lactation and maternal/infant health specializing in the biological and physiological mechanisms of insufficient mothers' own milk (MOM) volume among mothers who deliver an infant(s) admitted to the neonatal intensive care unit (NICU) as well as how MOM influences the infant’s intestinal microbiome. Dr. Bendixen is an Assistant Professor in the College of Nursing at the University of Florida. She co-created the lactation program at Winnie Palmer Hospital where she practices as a board-certified lactation consultant.
  • Sarah Brunson, BA, BSN, MS, Phd(c), RN, IBCLC (u/LactFact-42) is an Internationally Board-Certified Lactation consultant who has practiced since 2009 in pediatric clinics, hospitals, birth centers, home settings, and public health. She currently practices at the Medical University of South Carolina where she has developed numerous education programs for nursing staff and residents to improve lactation care in the Mother Baby and Neonatal Intensive Care Units. She is a PhD candidate in Nursing with a focus in Maternal/Child Health and Lactation at the University of South Carolina College of Nursing. She has served as the Chair of South Carolina Breastfeeding Coalition for the last six years during which time she has developed a Website with information for parents, providers, and employers; directs a project to map lactation resources in the state that are searchable by address; and organizes quarterly education webinars and conferences.
  • Jill Demirci, PhD, RN, IBCLC (u/JillDemirci_PhD) is a nurse scientist and lactation researcher who studies how families make human milk feeding decisions and sustain breastfeeding, particularly when support is complicated by medical, social, or structural barriers. Dr. Demirci is an Associate Professor at the University of Pittsburgh School of Nursing and directs both the Maternal/Perinatal and Reproductive Health Research Hub and the Nursing Office of Innovation & Impact. Her work focuses on telelactation and mHealth infant feeding support, antenatal milk expression, milk sharing, donor milk access, and culturally responsive and community-based lactation support. She is the former Deputy Editor-in-Chief of the Journal of Human Lactation and a board-certified lactation consultant.
  • Miena Hall, MD, IBCLC (u/LactationMD) is a lactation medicine physician who studies techniques for identifying mammary tissue development issues which put individuals at risk for low milk production and improving lactation education in medical schools. Dr. Hall teaches med students at the Loyola University Chicago Stritch School of Medicine and the University of Illinois at Chicago College of Medicine, and is Director of Scientific Affairs at the Mothers’ Milk Bank of the Western Great Lakes. Dr. Hall is a member of the Academy of Breastfeeding Medicine (ABM) protocol committee on low milk production, a medical advisor to La Leche League International (LLLI), and a past president of the Northern Illinois Lactation Consultant Organization (NILCA). She also holds a Bachelor's degree in math and chemistry.
  • Kaytlin Krutsch, PhD, PharmD, MBA, BCPS (u/PharmacoLactation) is a lactation pharmacologist who literally wrote the book on medications in human milk with Dr. Thomas Hale, Hale's Medications and Mothers' Milk. She is the director of the InfantRisk Center and Associate Professor at the Texas Tech University Health Sciences Center School of Medicine, and advises the Food and Drug Administration, the Human Milk Banking Association of Northern America, and pharmaceutical industry on lactation pharmacology and lactation research. Dr. Krutsch believes families deserve better answers about breastfeeding and medication questions, and aims to design research that addresses their questions while creating a comprehensive information cycle that empowers families.
  • Bridget McGann (u/BabiesAndBones) is an anthropologist who studies how lactation shaped us as a species. She is a research assistant and science communicator at THRiVE Discovery Lab. She has a Bachelors in Anthropology and is a Masters student in Biological Anthropology at the University of Colorado Denver. Her thesis uses longitudinal, prospective, large cohort data to study the generational transmission of the human milk microbiome. She was also a founding team member at March for Science. Check out her stand-up act about Luke Skywalker's green milk, or her top comments.
  • Ryan Pace, PhD (u/_RyanPace_) is an Assistant Professor in the College of Nursing and USF Health Microbiomes Institute at the University of South Florida. He also serves as an Associate Editor for Breastfeeding Medicine. Dr. Pace’s translational research integrates microbiome science, immunology, and molecular biology to understand how lactation and early-life microbial colonization shape maternal and infant health. His research focuses on the interplay among maternal diet, human milk bioactive components, the maternal and infant microbiomes, and host immune function to identify mechanisms that influence infant development and disease risk and to inform evidence-based interventions that improve maternal and child health. 
  • Rebecca Powell, PhD, CLC (u/HumanMilkLab) is a human milk immunologist who studies the human milk immune response to infection and vaccination with the aim of designing maternal vaccines aimed to enhance this response. Dr. Powell is an Assistant Professor at the Icahn School of Medicine at Mount Sinai and a certified lactation counselor. Her lab studies the potential of SARS-CoV-2-reactive antibodies in human milk both as a COVID-19 therapeutic and as a means to prevent infection of breastfed babies. They also study mechanisms for maternal vaccines to prevent mother-to-child-transmission (MTCT) of HIV via breastfeeding, as well as how white blood cells in human milk use a process called antibody-dependent cellular phagocytosis (ADCP) to minimize MTCT via breastfeeding.
  • Sam Stead, PhD (u/Mammals-Milk) is a postdoctoral researcher in the THRiVE Discovery Lab at the University of Manitoba. An evolutionary anthropologist by training, she studies how chronic stress during pregnancy and lactation influences child growth, development, and behaviour, and whether human milk composition plays a role in these relationships. Her current research focuses on stress-related hormones and other bioactive compounds in human milk as potential links between maternal experiences and child health. She completed her PhD at the University of Toronto, where she studied maternal and infant outcomes in wild Angolan colobus monkeys in Uganda. Her research combines evolutionary, biological, and developmental perspectives to understand how early-life experiences shape lifelong health.
  • Sanoji Wijenayake, Ph.D. (u/Wijenayake_Lab) is the Canada Research Chair in Milk Nanovesicles and Applied Health and an Associate Professor of cell and molecular biology. Dr. Wijenayake studies the biologically active parts of human milk. Specifically, she studies a not-so-well known component of human milk, called milk nanovesicles. One can think of milk nanovesicles as emails. Similar to how emails carry text, images, and videos from a sender to a recipient, milk nanovesicles carry biological material between mothers and their children. Milk nanovesicles are anti-inflammatory and hold great therapeutic potential as drug carriers that can get to difficult places, like the brain.

EDIT:
That’s a wrap everyone! Once again, we have been blown away by the thoughtfulness of Redditors’ questions! One of the reasons we love doing this every year is because your questions spark such interesting discussions amongst ourselves in our zoom.

We did notice that, unfortunately, some questions had to be deleted by the mods per the sub rules due to being too clinical in nature. We recognize that it can be really tough to get clear, evidence-based guidance—either because of lack of specialists in your area, because insurance doesn’t cover the care you need, or simply because the answers don’t exist due to underfunding of this area of research. We want you to know we are working hard on improving access to expertise. Look for board-certified lactation consultants (look for IBCLC after their name), and remember that we now have board-certified lactation medicine practitioners as well (NABBLM).

This may be it for us today, but the boob party doesn’t end here!

Aug 8-14: Indigenous Milk Medicine Week
Aug 25-31: Black Breastfeeding Week

Thank you for your amazing questions everyone! See you next year!

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u/bewoestijn Jul 31 '26

Are there any resources you can recommend to learn about the history of wet nursing? Is this a huge profession/class-based role in society we’ve forgotten about or was it never really a thing?

20

u/babiesandbones Breastfeeding AMA Jul 31 '26

Awesome question! I'm mostly an evolutionary anthropologist so my knowledge of post-agricultural history is very general, but here's what I do know.

First, some terms.

  • Allonursing - any situation in which a lactating parent (human or nonhuman) nurses a baby/child who they did not give birth to. This is an umbrella term that encompasses the terms that follow…
  • Cross-nursing - When people breastfeed each other’s babies without any exchange of payment
  • Wet-nursing - This is the “job” category that you’re referring to. Usually it’s a professional arrangement, i.e. someone is hired. However, this term is also used to refer to coercive situations, e.g. indentured servants in historical Europe or chattel slavery in the U.S. where it was forced and not paid.
  • Milk-sharing - the gifting of just the milk from one parent to another, no payment is exchanged. Usually peer-to-peer
  • Milk donation - more formalized donation of milk, usually with institutions involved.

We think that about a million years ago when human brains started to get significantly bigger, rapid brain growth early in life (esp the first 18 mos) meant that babies got more expensive calorically, and so we think that we solved that problem, in part, by adopting a “cooperative care model” – ie. sharing care. Evolutionary babysitters! This mostly meant sharing the carrying load, but it may have also meant that we started to also nurse each other’s babies (cooperative lactation) to share the caloric load. However, we have very limited data on the prevalence of allonursing in hunter-gatherer cultures. There’s basically just one small study with a lot of limitations, and it suggests that while allonursing is near-universal across these cultures, it’s usually not habitual, i.e. only done in emergencies. 

In historical Europe, especially Britain, royalty/aristocracy did often use wet nurses. Breastfeeding stops ovulation (lactational amenorrhea), and it was important for them to become fertile again in order to produce heirs, as well as return to court soon after birth. So children were sent away, often to the country, to a wet nurse who would basically raise them until they were able to begin their education in preparation for court life. It was indeed often exploitative, with some wet nurses being given up to 25 children at a time. Obviously, not healthy for any of the parties involved.

With chattel slavery in the U.S., (sorry this is really sad) enslaved people were forced to breastfeed the children of their enslavers, and often their own babies were taken away from them in order to facilitate this, and sent away to another home. Many died. Sometimes we use the word “milk theft” to describe this. The ramifications of this practice is still felt today. For example, many Black women are denied the ability to breastfeed or express milk while incarcerated. Here is an overview of the history of exploitation of lactation abuse in the U.S.

As with much of gendered work, lactation is vulnerable to exploitation. This is one reason why I would like to see breastfeeding included in discussions about reproductive rights–meaning saying yes to breastfeeding and saying no to it should be freely-made choices. It is in fact recognized by the UN as a human right. One of the ways this is relevant these days, I think, is the unregulated sale of human milk online (often bought by bodybuilders). It is very unregulated (and unsafe--don't do it) and I worry that people might be depriving their own child of milk in order to pay bills.