TOADtalk: The Magic of Human Milk
Ms. Grant embraces the biological changes that accompany pregnancy.
As the months go by in a Thacher school year, students and faculty members learn about each other in a thousand different ways, times, and contexts: around the breakfast or formal dinner table, in a sunshiny moment on the Pergola or a sunset shared on a trail, at the whiteboard in a classroom, lab, studio or seminar circle, at practices and games and rehearsals, at coffeehouses and Open Houses, in dorm common rooms, and in Suburbans on highways or back roads on the way to community service projects, field trips, cultural excursions, or athletic events. Then there’s each faculty member’s TOADtalk. Monday morning’s all-School Assembly launches with whatever the Teacher On Active Duty wishes to share—a reflection, a story or song, a demonstration of some sort, or a simple poem. In this way, every week of the school year, the community gains a new window into the mind or heart or spirit of one of our own.
Heather Grant, whose TOADTalk is featured below, has worked at Thacher since 2006. Ms. Grant teaches chemistry and biology in the science department and coaches jv girls' soccer and varsity girls' lacrosse. She lives on campus with her husband and their two dogs, Gus and Sherman.
Good morning! I’m Ms. Grant for those of you who haven’t met me yet. All of you might have noticed that I am, in fact, growing a human.
Heather Grant, whose TOADTalk is featured below, has worked at Thacher since 2006. Ms. Grant teaches chemistry and biology in the science department and coaches jv girls' soccer and varsity girls' lacrosse. She lives on campus with her husband and their two dogs, Gus and Sherman.
Good morning! I’m Ms. Grant for those of you who haven’t met me yet. All of you might have noticed that I am, in fact, growing a human.
Knowing that I’d be up here in front of all of you like this, I was determined to talk about something, anything, that would distract from the protruding obviousness of my condition. I contemplated presenting the superhero powers of sea slugs OR the amazing diversity of protein form and function in the eukaryotic cell. Either of these seemed like a safe topic that would distract you enough to let me survive these moments we have together relatively unscathed. But then I remembered that sometimes my favorite way of diffusing my most awkward or uncomfortable moments is to just run straight ahead and smack right into it, so here goes.
I’m take this opportunity, before all of you today to let you know just how I feel about pregnancy—to get it out of the way in one fell swoop.
For me, being pregnant is infinitely weird. And fascinating.
Like most expectant moms, I’ve been reading all sort of blogs and books and consulting apps that compare the size of my soon-to-be offspring to vegetables—right now it’s in the butternut squash phase. As a science teacher, I’ve also found the whole process to be amazing in the “use yourself as case study” kind of way, but not so much in the “isn’t the miracle of life so magical” kind of way. The good news is that I’ve always seen biology as a means for explaining and defining the “magic” that exists in the living world.
So here is some research that I’ve read recently about the connection between moms and babies that helps explain that the “unspoken bond” that exists between them.
First, we’ll start out with the fascinating biochemistry of human milk.
I think it’s safe to assume that all of you have heard of the benefits of breastfeeding and the recommendations that babies are breastfed, whenever it is possible for mom and baby to do so, for at least the first six months of life. Researchers have been exploring the details of where those benefits come from.
Here are some of the latest facts from a number of articles on the topic:
Human milk “contains all the vitamins and nutrients a baby needs in the first six months of life...and it has many germ- and disease-fighting substances that help protect a baby from illness.”
It is filled with microbes—the same type of “active cultures” that adult humans seek out in probiotics or yogurt or kombucha come naturally in breast milk and help establish the colonies of helpful microbes in infant intestines.
“Nutritionally, breast milk is a complete and perfect food, an ideal combination of proteins, fat, carbohydrates, and nutrients.” The most surprising components are the 150 oligosaccharides (bio students might recognize that term for a carbohydrate that is 3-10 monosaccharides in length) that are unique to human milk, meaning that they are only produced by humans. Even more amazing is that, “these oligosaccharides can't be digested by infants; they exist to feed the microbes that populate a baby's digestive system.”
You’ve probably also heard that breastfeeding improves the immune system of babies, by passing on antibodies that the mom produces and will help babies fight off infection. The most interesting aspect of the nutrients and immune response components of human milk is this:
“The nutritional and immunological components of breast milk change every day, according to the specific, individual needs of a baby.”
What that implies is a communication from the baby to the mom, requesting certain nutrients and antibodies given the needs of baby. And that’s just what happens. The mom’s body has sensory receptors that allow her to receive chemical messages from the baby, the mom’s nervous and immune systems respond by adjusting the balance of nutrients in the milk she produces and by producing the correct antibodies for any foreign material that threatens the baby’s health.
As humans go through the course of the day, our bodies produce different chemicals that contribute to our sleep-wake cycle or circadian rhythms. Those hormones get passed from mom to baby in breastmilk, communicating day and night cycles to the baby through biochemical messages—creating a molecular difference between “day” and “night” milk and helping the infant regulate their own sleep schedule.
Lastly, human milk contains pluripotent stem cells, which pass from mom to baby, which are hypothesized to help infants with “tissue development,” metabolic health, and immune function. The presence of these cells in breast milk can have larger implications, however, because these are the type of stem cells that have the ability to differentiate into any other type of cell in the human body. The only other known source of pluripotent stem cells are from embryos, so research using these cells for the treatment of disease or understanding of development has been limited due to the ethical implications of using embryonic tissue for research. The potential of obtaining the same type of cells from breast milk is very exciting to the research communities related to these fields of study.
The other type of mother to child communication is related to research that shows that the flow of cells between mom and baby in utero is much more open than previously thought. It turns out that every time a woman becomes pregnant, whether or not she is able to carry the baby to full term, cells migrate from the baby to the mom. These cells are also pluripotent and once in the mom they travel all over her body and specialize into cardiac tissue in the heart, neurons in the brain, or any number of different body tissues.
Researchers first found these small collections of fetal tissue scattered in the bodies of mothers, when they took tissue samples and performed genetic tests looking for Y chromosomes—which I’m sure most of you know should NOT be found in the tissue of women. In surprising numbers of the individuals tested, tissue from their sons were found scattered throughout the women’s bodies in a condition called “fetal microchimerism.”
And it turns out that when a woman develops a disease like cancer or rheumatoid arthritis, these cells flock to the site of the disease and increase in number. The research is pretty clear about those points—the movement of cells from the developing baby to the mom, the differentiation of the cells to perform normal tasks in the mom’s body (sometimes for the full course of her life), and with the onset of disease, the cells can be found in higher concentration. What is still being explored by scientists in this field is what effect the cells have on the moms and how, exactly, they contribute to her overall health. The answers to those questions are not clear and as tempting as it is to label some fetal cells as coming from “bad” or “good” babies based on whether they seem to cause disease or help fight it, it looks like the explanations won’t be that clear.
Aside from the contributions to our understanding of cell-to-cell communication, the mother-fetal connection, and developmental biology, this research also calls into question ideas of cellular or corporeal autonomy. Because each individual is more like a cellular mosaic, mostly composed of cells of own unique genetic makeup, but also with cellular contributions from previous generations (and future ones in the case of moms).
Bringing this talk back to Thacher—moving away to boarding school can be a tough transition—both for students and parents. That feeling of separation can be difficult, overwhelming at times, but you should feel comforted by the fact that you are never too far from at least your mom, since it’s likely that you’re literally carrying a little bit of her with you at all times.
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