Hey everyone, welcome back to My Weird Prompts. We are coming to you from our living room here in Jerusalem, and I have to say, the air is finally starting to clear up after that massive dust storm yesterday. I am here with my brother, as always.
Herman Poppleberry, at your service. And yeah, that dust was something else. I think I spent half the day yesterday just cleaning the grit off my rare book collection. But we have something much more interesting than the weather to talk about today. Our housemate Daniel sent us a voice note this morning that really got me thinking about the intersection of ancient biology and high technology.
It is a fascinating one. Daniel was asking about breastfeeding, specifically in the context of where we are now in February of twenty twenty-six. We have got all this incredible synthetic technology, we have got precision fermentation, we have got lab-grown proteins that are nearly identical to the real thing. And yet, the global medical consensus is still so heavily weighted toward breastfeeding. Daniel wanted to know why formula, even with all our advancements, still is not considered a full equivalent. What is the secret sauce, so to speak?
It highlights the fundamental difference between nutrition and biology. Most of us think of milk as a list of ingredients, right? You have got your proteins, your fats, your carbohydrates, and your vitamins. If you can match those numbers on a label, you should have the same product. But what we are learning, and what research has really leaned into over the last few years, is that breast milk is not just food. It is a living, bioactive communication system.
A communication system. I like that framing. It suggests that there is information being passed between the mother and the baby, not just calories.
That is the key thing. It is almost like a biological software update that happens multiple times a day. When we look at formula, even the most advanced ones we have in twenty twenty-six, they are essentially static. You buy a tin, and the composition of that powder is the same on Monday as it is on Friday. But breast milk is dynamic. It changes based on the age of the baby, the time of day, and even the health of the mother and the infant.
So, let's break that down. You mentioned it is a living fluid. I know one of the big talking points is always the immune system. How does that actually work in practice? Is it just antibodies?
Antibodies are a huge part of it, specifically Secretory Immunoglobulin A, which is often called the first line of defense. But it goes way beyond that. One of the coolest things is what researchers call the retrograde flow, or more colloquially, the backwash effect.
Wait, I have heard of this. This is the idea that the baby’s saliva actually tells the mother’s body what is going on?
That is right. When a baby latches, a vacuum is created, and a small amount of their saliva is actually sucked back into the mother’s nipple. Within that saliva are pathogens—bacteria or viruses that the baby has been exposed to in their environment. The mother’s mammary glands have lymphatic tissue that essentially scans that saliva. If it detects a threat, like a cold virus or a bacterial infection, the mother’s body starts producing specific antibodies for that exact pathogen. Those antibodies then show up in the milk within hours. It is a real-time, personalized pharmacy.
That is incredible. So, if the baby is starting to get sick, the mother’s body recognizes it before the baby even shows major symptoms and starts sending the medicine through the milk. You can’t put that in a tin of formula.
No, you really can’t. And it is not just antibodies. We are talking about white blood cells, too. In the first few days after birth, in that thick yellow milk called colostrum, there are millions of live white blood cells. These are leukocytes that can actually cross the baby’s gut wall and enter their bloodstream to help fight off infections. It is a level of biological integration that we just haven’t been able to replicate synthetically.
I remember reading something about the microbiome as well. We talk a lot on this show about gut health, but it seems like breast milk is the original architect of the human microbiome.
Oh, definitely. This is where we get into one of my favorite topics: Human Milk Oligosaccharides, or H M Os. For a long time, scientists were baffled by these. They are the third most abundant solid component in human milk, after lactose and fats. But here is the kicker: babies cannot digest them. They have no nutritional value for the infant.
So why are they there? Why would the body expend so much energy creating something the baby can’t even eat?
Because they aren’t for the baby. They are for the bacteria in the baby’s gut. Specifically, a type called Bifidobacterium infantis. These H M Os act as a prebiotic, a very specific fertilizer that ensures the right kind of bacteria colonize the infant’s gut. This prevents harmful bacteria like E coli or Salmonella from taking hold. It is basically the mother’s way of terraforming the baby’s internal ecosystem to make it a safe environment.
It is amazing to think that a significant portion of the energy a mother puts into making milk is actually destined for bacteria, not the child. It shows how fundamental that symbiotic relationship is from day one. But Herman, we do have synthetic H M Os now, right? I have seen them advertised in high-end formulas lately.
We do, and that is a major step forward. But there is a catch. There are over two hundred different types of H M Os in human milk, and each mother produces a unique profile based on her genetics and her environment. Most formulas today might include two or three of the most common ones, like two-prime-fucosyllactose. It is like trying to recreate a rainforest by planting three types of grass. It is better than nothing, but it lacks the incredible complexity and diversity of the natural version.
That makes sense. It is the difference between a supplement and a whole food. But what about the things that aren't even chemical? You mentioned earlier that it's a communication system. Does that extend to hormones and circadian rhythms?
It certainly does. This is something that often gets overlooked. The composition of breast milk changes depending on the time of day. Morning milk is high in cortisol and amino acids that promote alertness. Evening milk, on the other hand, has much higher levels of melatonin and tryptophan, which help the baby develop their own circadian rhythm and fall asleep.
So, if you are pumping milk and giving it in a bottle, you actually have to be careful about when you give it?
Ideally, yes. If you give a baby morning milk at ten p.m., you might accidentally be giving them a shot of biological espresso. Formula, again, is static. It doesn't have those hormonal fluctuations that help train the baby’s internal clock.
It seems like the more we learn, the more we realize that breast milk is essentially a bridge. It is the transition from being physically connected in the womb to being an independent biological entity. It provides the training wheels for the immune system, the gut, and even the brain.
That is a great way to put it. And speaking of the brain, we have to talk about the long-chain polyunsaturated fatty acids, like D H A and A R A. While these are now added to almost all formulas, the way they are packaged in breast milk is different. They come in these little structures called milk fat globule membranes, or M F G Ms. Recent studies from twenty twenty-four and twenty twenty-five have shown that these membranes play a huge role in neurodevelopment and even in protecting against infections. Most formula manufacturers have historically stripped these away because they are difficult to process, though that is starting to change in the premium market.
I think one of the things Daniel was touching on in his prompt was the idea of nutritional equivalents. We can match the calories, the protein grams, and the fat content. But it sounds like the nutrition is almost the least interesting part of what is happening here.
I think that is a fair assessment. If you are just looking at growth charts, babies on formula grow just fine. They hit their milestones. But when you look at the long-term health outcomes, that is where you see the subtle but significant differences. We see lower rates of asthma, obesity, and type one diabetes in children who were breastfed. We see better cardiovascular health later in life. And a lot of that comes back to epigenetics.
Epigenetics. That is the way our environment can turn certain genes on or off, right?
That is right. And breast milk is full of micro R N As. These are tiny molecules that don't code for proteins themselves but instead act as regulators for other genes. There are thousands of these in human milk, and they survive the infant’s digestion to enter the bloodstream and tissues. They can literally influence how the baby’s genes are expressed, potentially programming their metabolism and immune system for decades to come.
That is a lot of responsibility for a fluid. It is almost like a second set of genetic instructions being passed down after birth.
It really is. And we are still just scratching the surface. One of the most mind-blowing discoveries of the last decade is the presence of stem cells in breast milk.
Stem cells? Like, the cells that can turn into any other kind of cell?
Yes. Live human stem cells. When a baby drinks breast milk, these cells survive the stomach and can migrate into the baby’s brain, heart, liver, and bones. There is evidence suggesting they actually integrate into those organs—a phenomenon called microchimerism—and become part of the baby’s body. We don't fully understand why yet, but it’s possible they are there to help with rapid organ development or repair.
Okay, that is wild. The mother is literally giving parts of her own cellular makeup to help build the baby’s organs. That is a level of intimacy that goes way beyond just feeding.
It really shifts the perspective, doesn't it? It is not just a meal; it is a biological transplant in every feeding.
So, Herman, given all of this, why is there such a push for synthetic alternatives? If breast milk is this miracle fluid, why are we spending billions of dollars trying to recreate it in a lab?
Because, as much as we talk about the biological perfection of breast milk, the reality of breastfeeding is incredibly difficult for many people. There are medical reasons, like low supply or medications that aren't compatible with nursing. There are societal reasons, like the lack of parental leave or the pressure to return to work. And there are personal reasons. Breastfeeding is an enormous physical and emotional demand on the mother.
Right, and I think that's an important point to make. We are talking about the science here, but we also have to acknowledge the human element. Formula has been a literal lifesaver for millions of babies. Without it, many children simply wouldn't have survived.
That is so true. And that is why the research we are talking about is so important. The goal isn't to make parents feel guilty for using formula. The goal is to understand breast milk so well that we can make formula better. If we can identify which micro R N As or which H M Os are the most critical for long-term health, we can start adding them to synthetic versions. We are trying to close that gap, even if we can never fully bridge it.
You know, I was looking into some of the twenty twenty-six startups that are working on this. There are companies now, including some right here in Israel like Wilk, that are using lab-grown human mammary cells to produce cultured human milk. They are trying to get the cells themselves to do the work in a bioreactor, rather than just mixing chemicals in a vat.
I have been following them too. It is a fascinating approach. If you can get actual human cells to secrete the milk, you might get those milk fat globule membranes and some of the H M Os that are currently missing. But you still wouldn't have that real-time feedback loop with the baby’s saliva. You wouldn't have the mother’s antibodies changing in response to a local flu outbreak. You wouldn't have the stem cells.
It’s the living part that remains the final frontier. You can grow the cells, but you can’t grow the relationship between two specific immune systems.
You're right. It is a biological dialogue. And a dialogue requires two participants who are present and interacting.
So, if we look at the recommendations from organizations like the World Health Organization or the American Academy of Pediatrics, they usually recommend exclusive breastfeeding for the first six months. Given what we have talked about, that makes a lot of sense. The first six months are when the immune system and the gut microbiome are at their most vulnerable.
And that is the critical window for that terraforming we talked about. By six months, the baby’s own immune system is starting to take over, and their gut is becoming more robust. But even after six months, the benefits continue. The composition of the milk changes again as the baby starts eating solid foods, providing complementary nutrition and continued immune support.
I think one of the misconceptions people have is that after a certain point, breast milk just becomes water or loses its value. But from what you are saying, it sounds like it just evolves.
It never becomes water. In fact, in the second year of breastfeeding, the concentration of certain antibodies actually increases because the toddler is moving around more, putting more things in their mouth, and being exposed to more germs. The milk adapts to the child’s changing lifestyle.
It is like an adaptive security system that scales with the user’s risk profile.
I love that. That is exactly what it is.
So, for the listeners who might be parents or soon-to-be parents, what are the practical takeaways here? We have talked a lot about the high-level science, but how does this translate to real-world choices in twenty twenty-six?
I think the first takeaway is to appreciate the complexity. If you are able to breastfeed, even for a short period, you are providing a biological foundation that is incredibly unique. Even a few weeks of colostrum and early milk provides a huge boost to the immune system.
And if you can’t breastfeed, or choose not to, what should you look for in a formula today?
Look for those bio-inspired ingredients. In twenty twenty-six, we have much better access to formulas with multiple H M Os. Look for those that include milk fat globule membranes if they are available. And pay attention to the source of the proteins. Some of the newer formulas are using precision-fermented human-identical proteins rather than just modified cow’s milk. It is not the same as the living fluid, but it is a much closer nutritional match than what we had even five years ago.
It is also worth mentioning donor milk. In many cities now, including here in Jerusalem, there are milk banks where mothers with an oversupply can donate to those in need. For premature babies especially, donor human milk is often treated as a medical necessity because it significantly reduces the risk of serious intestinal issues like necrotizing enterocolitis.
That is a very important point. For preemies, the medicine aspect of breast milk is even more pronounced. Their systems are so fragile that the protective qualities of human milk are often the difference between a smooth recovery and major complications.
You know, Herman, thinking about all of this makes me realize how much we still have to learn about the human body. We think of ourselves as these independent individuals, but the more we look at things like breastfeeding or the microbiome, we see that we are actually these deeply interconnected systems. We are literally built from the biological contributions of others.
It is a very humbling realization. We spend so much time focusing on our technology and our ability to engineer solutions, but nature has had millions of years to perfect these systems. Sometimes the best
