Mothers and babies communicate through breastmilk? At the moment that’s wishful thinking.

Soft photo mother feeding breast her baby at home

Lactivists are constantly making claims about breastfeeding that aren’t supported by the scientific evidence.

I’ve written extensively about debunked claims that breastfeeding prevents obesity, diabetes, high blood pressure and a host of other chronic conditions. Those erroneous claims can be traced to the confounding variables found in most breastfeeding studies. Women who breastfeed are wealthier, more educated and have greater access to healthcare. What appears to be a benefit of breastfeeding, actually turns out to be a benefit of higher socio-economic status.

As those claims are being rolled back, lactivists have advanced a new, rather extraordinary claim: that mothers and babies communicate through breastmilk.

There are far simpler explanations for the presence of bioactive compounds in breastmilk than spit backwash.

In The More I Learn About Breast Milk, the More Amazed I Am, Angela Garbes writes:

According to Hinde, [Katie Hinde, a biologist and associate professor at the Center for Evolution and Medicine at the School of Human Evolution & Social Change at Arizona State University] … If the mammary gland receptors detect the presence of pathogens, they compel the mother’s body to produce antibodies to fight it, and those antibodies travel through breast milk back into the baby’s body, where they target the infection.

But that’s not all:

Even before babies have any concept of time, breast milk helps them understand certain hours from other hours, night from day.

“Milk is so incredibly dynamic,” says Hinde. “There are hormones in breast milk, and they reflect the hormones in the mother’s circulation. The ones that help facilitate sleep or waking up are present in your milk. And day milk is going to have a completely different hormonal milieu than night milk.”

Or as Hinde said to me in a Twitter conversation:

… [T]his is one example of the complex biofeedback system of breastfeeding that many people don’t know & should.

Actually, it’s yet another example of the white hat bias toward breastmilk that leads researchers like Hinde to make claims that far, far outstrip the existing scientific evidence.

What is white hat bias?

‘White hat bias’ (WHB) [is] bias leading to distortion of information in the service of what may be perceived to be righteous ends…

Indeed white hat bias was first described in association with breastfeeding research:

Certain postulated causes have come to be demonized (… formula feeding of infants) and certain postulated palliatives seem to have been sanctified.

Let’s look at the ways that white hat bias has led to outsize claims about the properties of breastmilk.

Breastmilk researchers start with certain fixed, unquestioned assumptions about breastmilk such as:

  • Breastmilk is assumed to be an unalloyed “good.”
  • Components of breastmilk are assumed to be beneficial.
  • The components of breastmilk are assumed to be directed in whole or in part toward the benefit of the baby.

Breastmilk is definitely an excellent way to nourish an infant. But breastmilk, like any biological product, is not perfect. Sure, it’s the product of millions of years of evolution, but evolution can only work with what it has available; it can’t create de novo. For example, it would confer a tremendous survival advantage to have eyes in the back of our heads, yet we don’t have them. Why not? The animal genome by and large is restricted to a body plan with two eyes at the front or sides of the head. Evolution can’t spontaneously generate four eyes from the genes for two eyes. Evolution cannot spontaneously add nutrients to breastmilk simply because they are needed by the baby. They must be available in the mother’s body first.

Not all components of breastmilk are beneficial. Breastmilk is a bodily fluid derived from other bodily fluids. Therefore, it is has components that reflect what is in the maternal bloodstream whether those components are good (antibodies) or bad (viruses, medications, industrial chemicals) for the baby. HIV, the virus that causes AIDS can be found in human breastmilk of mothers infected with HIV and can be passed to the baby. The virus is bad for the baby, but since it was in the fluid used to create breastmilk, it ends up in the breastmilk, and often kills the baby. It is entirely unjustified to assume that the presence of a bioactive compound in breastmilk means that it’s there for a good reason.

Prof. Hinde was irritated with my criticism of her claims and sent a bibliography salad of references to me through Twitter.

At the very best, those reference show correlations between certain conditions and certain components of breastmilk. But correlation is not causation.

There are 9 criteria, known as Hill’s Criteria that can tell us when a correlation shows causation. One of those criteria is “consideration of alternative explanations.” Before claiming that A caused B, you must consider and rule out the more likely possibility that B occurred for a reason entirely independent of A. If you graph consumption of organic food against incidence of autism, you’ll find that as the consumption of organic food has risen over the past decades, the incidence of autism has risen almost in parallel. That does not mean that organic food causes autism.

Hinde and other researchers on breastmilk have noted that when babies are sick, the antibodies content of breastmilk rises. They’ve even proposed an extraordinary mechanism for how the baby communicated to its mother that it was sick. Their theory is known as “spit backwash.” Baby saliva is literally sucked into the breast where the mother’s body senses the pathogen and makes antibodies in response.

But there is another far simpler, far more likely explanation. It’s hard for two people to be much closer than a mother and her feeding infant. If a baby has a cold, for example, the mother can simply BREATHE IN the virus expelled when the baby sneezes and make antibodies to the virus to protect HERSELF from the cold. Those antibodies then end up in the breastmilk incidentally as a result of being in the mother’s bloodstream. If researchers had looked, they would likely have found that the father and siblings were making the same antibodies as the mother, not to transmit them to the baby, but to protect themselves.

Is it possible that the mother made the antibodies as a result of saliva being backwashed into the breast and created them in order to protect the baby? Sure, it’s possible, but you’d need a great deal more evidence to draw that conclusion. You’d need to show that the mother would make the same antibodies even if she hadn’t had oral and nasal exposure to the baby’s secretions. Furthermore, you’d need to show that those antibodies made it into the baby’s bloodstream and are biologically active there. As yet, no one has shown anything of the kind.

How about the claim that breastmilk helps facilitate infant sleep?

Yes, there are sleep promoting compounds in breastmilk produced at night, but that doesn’t mean they are there to help the baby sleep. They may be there simply because the mother is tired. In other words, the presence of these compound is incidental. Is it possible that they induce sleep in the infant? It’s possible but not particularly likely since babies have their own sleep patterns that are, sadly, unrelated to their mothers’ need and desire for sleep.

When I questioned Hinde more closely on these types of claims and presented simpler alternative explanations than spit backwash, she began walking them back:

I agree that there are reasons for maternal antibodies to be protecting the mammary gland & things can be byproducts… but I think you are also confusing the matter of science publications that grapple w/ these complexities… & aspects of the science communicated broadly: the article discusses this as one potential pathway… there is evidence for that… but doesn’t make arguments that it the ONLY pathway or that this is the ONE function of that pathway.

This is a far more nuanced view, but hardly the view that she has been presenting in her interviews and writing for laypeople where she insists that “mammary gland receptors detect the presence of pathogens, they compel the mother’s body to produce antibodies to fight it, and those antibodies travel through breast milk back into the baby’s body, where they target the infection.”

Do mothers and babies communicate through breastmilk? At the moment, that’s wishful thinking abetted by white hat bias. The existing scientific evidence shows that there are antibodies and other bioactive compounds in breastmilk; those studies are small, show only correlations, and are themselves affected by white hat bias.

There are far simpler explanations for the presence of antibodies and other bioactive compounds in breastmilk than spit backwash. They are created by the mother to protect the mother. Any benefit to the baby has yet to be demonstrated.

  • It’s true that breast milk is fairly consistent, but ask any mother what happens if she eats a lot of chocolate, or drinks a quart of orange juice, or something with a lot of garlic. It will eventually cause a stomach upset in the baby. I suppose that’s a form of “communication” with the baby.

    • fiftyfifty1

      “ask any mother ”

      I never noticed that what I ate, even if extreme, had any effect on my babies.

      I’ve had a few patients tell me that what they ate affected their babies, but they were usually the same women who swore that all sorts of foods caused themselves all sorts of dramatic reactions, but then allergy testing was negative. Some people are prone to seeing correlation and assuming causation, especially when it comes to food.

      Garlic or OJ or chocolate causing a breastfed baby stomach upset? Even though the mom tolerated it fine in amounts orders of magnitude higher than the baby could have possibly received it? What would be the mechanism for that? I guess I would need some proof that such a thing were possible.

    • Cobalt

      My littlest didn’t nurse well after I had red wine (only one glass). White wine and beer didn’t bother him. I think it’s a flavor issue (yes, someone who can clearly communicate did do a taste test- the red wine taste did come through even 4 hours later). Some good science on how that all works would be nice.

    • demodocus

      K never had a problem with my garlic habit, but then he probably thinks sliced apples are supposed to taste a little garlicky.

    • Trixie

      Never ever happened to me, even once. I’m skeptical.

    • Mac Sherbert

      Yep. In the beginning I could only eat starches. Milk, orange juice, broccoli, beans, corn and other things I can’t remember caused major gas, ect. After a few weeks I could slowly start eating normal again.

  • Cobalt

    OT, I’m curious about the range of experiences you all have, my youngest (1 year already!) is being different from the other kids again and its weirding me out.

    He only wants to nurse twice a day most days, first thing in the morning and right after dinner (dinner is toddlerized versions of what everyone is eating at this point) and occasionally after lunch (baby food). That would be totally fine by me (really, I LOVE this schedule), but he doesn’t want to drink anything else. Not cow’s milk, not formula, not “toddler milk”, not water, not juice, not in a bottle, cup, sippy, whatever. He can use a sippy or bottle, he’s just not interested. He voluntarily gave up the pacifier a while ago, so that’s not an issue.

    Can that little fluid intake possibly be ok? Growth, weight, milestones, diaper output, etc are all normal. No markers for dehydration, and he’s comfortable and happy. Why is he being weird?

    • Guest

      I can’t speak to dehydration, but FWIW my son refused all milk after he weaned – cow’s milk (white, chocolate, strawberry), almond milk, coconut milk, and I gave up after that. His doctor completely didn’t care as long as he was eating foods containing adequate calcium, protein, and fat – and was staying hydrated. If I recall correctly at 18 months when I weaned him, he was nursing twice a day and not really drinking anything else. Good luck!

      • Cobalt

        Thanks. Good to know he’s not the only one, just the first one of mine to pull this particular quirk.

      • Mac Sherbert

        I had one similar to that weaned from Bf at 18 months. She would take formula so I gradually (over a period of weeks) mixed it with cows milk. She never had and still doesn’t have much interest in juice. It’s strange to me because first kid would drink anything and I had to limit fluids, but with 2nd kid I’m begging her to drink something on hot days.

    • Who?

      Tricky. If you’re worried about dehydration would he have some ice cubes or ice chips, perhaps made with something flavoured? Or maybe something a bit warm? Would he have something if you sat down with him and made a (nice) fuss of it somehow?

      Sounds like he’s generally fine, so perhaps so long as that continues decide to think about it again next week? These phases tend to pass before you know it, and it seems a lot faster if you’re not thinking about it all the time!

      • Cobalt

        He really seems normal, by any measure other than intake. I hadn’t thought of ice/popsicles, I still think “baby” instead of “toddler” too often, he’s so much smaller than my other kids (all school age). It’s definitely different with such an age gap, not like having a young toddler, an older toddler, and a preschooler like last time. He’s also so different in general attitude and preferences, I’m having to learn new tricks again.

        • Who?

          It must be really different having that age gap. He would need things the others are long past, and probably wants at least some of what they have/do as well.

          Sounds like he’s fine, no doubt learning to be his own person with the older ones to differentiate from.

        • demodocus

          My 1 year old has been sucking down “pop’cles” this week. (Northern U.S. does not see 90* all that often)

        • Bugsy

          Have you heard of the Yonanas machine? We got one last month, and it’s awesome…toddler Bugsy loves making ice cream with it, and it would be a great additional way for your little guy to get fluids & fruits.

          • Cobalt

            I have not. But if it’s relatively cheap and easy, it sounds like it will fit right in here!

          • Bugsy

            I think they run about $40, but you might be able to get one cheaper w/ summer clearance sales. Ridiculously easy – just add frozen bananas and other frozen fruit, and it somehow comes out as soft-serve ice cream. Our favourite is bananas & cherries with some chocolate chips added in afterwards…yum!

    • Angharad

      My daughter doesn’t drink that little, but she doesn’t drink very much either, especially from cups. Our pediatrician said there’s water in lots of the food she eats, especially fruits and vegetables, and not to worry about it. I still worry about it so I try to give her juicy fruits like watermelon and oranges to eat.

      • Cobalt

        The purees might be where he’s getting his fluids, we’re still doing a meal and a snack of baby food.

    • fiftyfifty1

      The thirst drive extremely robust. Your kid will get enough liquid. Foods have lots of water in them.

    • Young CC Prof

      My grandfather pretty much never drank anything except milk with his morning cereal, and he lived to be 98. Maybe some people just don’t need a whole lot of fluids. Keep in mind fruits and veggies are a source of water.

      • Amy M

        Yes–I drink more than Cobalt’s toddler I guess, but my family thinks I’m a camel, because I drink very sparingly. If I am thirsty, I will go get something, but its pretty common that I’ll have a cup of tea in the morning, one at lunch, and maybe another with dinner-after dinner. So 3-4 cups of water or tea all day (I don’t usually drink soda). I know plenty of people who can’t go anywhere without a huge water bottle, so I guess there’s a wide range of normal thirst. Anyway, I would agree with the others here saying that if he’s acting healthy, and peeing ok, and eating enough, he’s probably getting enough fluids.

      • Roadstergal

        “Keep in mind fruits and veggies are a source of water”

        Fruit/veg in particular and food in general. That much-touted ‘8 cups of water a day’ study meant 8 cups from any source, and most of the subsequent media blitz failed to note that we get a lot of that without having to drink it separately.

        Tangential, but I still hear that one circulating, and it annoys me.

    • demodocus

      Why’s he being weird? He’s a toddler? If he’s comfortable, then it’s all good. If his fruit habit is anything like my 1 year old’s, it’s probably only something you have to watch if its one of those really nasty hot days. Purees are pretty liquidy too.

      • Cobalt

        He’s only being “weird” in the context of our particular set of kids. While the others all certainly have differences, this one is just a whole different kind of different and its throwing me off my stride. He’s within the range of normal for toddlers generally, just a new “breed” for our family. It’s like starting over in more ways than one.

        I want to make sure he is healthy and happy, but he needs a different set of markers for that than the ones I’ve been using for the last more-than-a-decade. I’m not confident I have the right ones, as they’re new.

        • demodocus

          Kind of like a brand-new parent all over again? *hugs*
          A friend of ours told us that when his son was born, it took a while fumbling through before they figured stuff out. Then their daughter was born and informed them they were *doing everything wrong!*

    • Dinolindor

      Oh I just went through this with my daughter last month when she turned 1! She was formula fed, but similar issues of just refusing to drink anything during the day. It took about 1.5 weeks to work out to a normal 2 cups of whole milk/day in her sippy cup. She never had too much interest in her bottles, so she always was at the low end of formula consumption/day, but this completely freaked me out. And then suddenly, she normalized and was fine. Hellish 1.5 weeks, but she had to muddle through on her own first, mother’s worrying be damned. I attempted to compensate with a lot of watermelon and other juicy foods, especially since there was a heatwave while this was going on. I hated my ped’s advice of “does she make tears when she cries? Then she’ll be fine”…but, well. She was fine, just took her time.

      • Cobalt

        “I hated my ped’s advice of “does she make tears when she cries? Then she’ll be fine”…but, well.”

        This is so me.

        “Doc, I’m worried about this thing.”

        “Has this, that, or the other happened? Does the kid have any indicators of being not fine?”

        “No”

        “The kid is fine.”

        “But how do I KNOW that?”

        “You’ll just have to accept the current state of the evidence.”

        This would really all be a lot easier with indicator lights!

        • KeeperOfTheBooks

          Or a manual. I swear, is it asking so much to get a freaking manual with each kid?!
          “Oh, Junior’s screaming again. He’s done that a lot lately. That indicates *thumbs pages* oh, he has two teeth coming in that we can’t see yet! Okay, Tylenol and extra snuggles, coming up!”

          • demodocus

            lol, 3 of my boy’s canines came through while he was on oxycodone for the broken leg last month.
            Which reminds me, anyone have a good recommendation for getting rid of the extra? I’m reluctant to just empty it down the drain. Don’t need high fish in the nearby lake 😉

          • theadequatemother

            you should return it to a pharmacy. This is what you are supposed to do with any left over narcotics. Did you know that over 50% of street narcotics are obtained from friends or family members and most teens that use illicit drugs get them from their parent’s medicine cabinet?

          • Ash

            you might be surprised that it’s legally allowed but that doesn’t mean a pharmacy will accept leftover medications for disposal. Some Walgreens sell a $5 mailing package for disposing of narcotics. Walgreens does not have a nationwide policy that they will dispose of the drugs for you for free.

          • demodocus

            I knew a lot of it was family prescriptions, though not a specific percentage.

          • Inmara

            Hear, hear! I was SO freaked out when realized that this baby is unique and nobody can tell me for sure what does he want when screaming and fussing. One month in, I’m a bit better with clues, but still not sure sometimes if he’s sleepy or going to poop or wants more food.

          • Who?

            No manual, and no instructions for re-insertion so you can have a go at starting again!

        • demodocus

          THis is also my husband.

    • Dinolindor

      Also, I assumed I was freaking out more because my son has a winter birthday, so he wasn’t going through this adjustment in liquid intake during a heatwave. I really can’t remember though, maybe I did freak out this much with him 3.5 years ago too.

      And also, I hear you on learning new tricks. I was just commenting to my mom about that with naps. Whenever my son was ready to drop a nap, he simply would not fall asleep at that nap time. With my daughter, she would sleep and then have crappy naps all day and continue with crappy sleep all night, until I went “duh! this is how she tells me she needs a change” and I stopped attempting a particular nap. My kids are night and day different personalities, and maybe I’ll actually remember that one day when it comes to looking for necessary schedule changes (among other things).

  • yentavegan

    I loved being a stay at home privileged breastfeeding mother. I bought into all the magic life affirming qualities unique to the breastfeeding dyad. However, when my brood got sick every single summer with first coxsackies then the next summer rosiola then the next year chicken pox I convinced myself that somehow my breastmilk prevented the illnesses from being life threatening. Of course in hindsight I appreciate that the confounding factors were access to medications, healthy foods and clean water….

  • Angharad

    I have to admit when my daughter was first born I read that night milk contains hormones to make baby sleepy at night. I was mostly pumping and supplementing with formula, and I felt extra pressure to feed her the “right” milk at bedtime so it wouldn’t keep her up. I don’t think it made any difference really. Certainly nobody else could tell if she’d had night-pumped milk or day-pumped milk.

    • Sullivan ThePoop

      Formula must be the right milk then because it makes babies really sleepy

      • Inmara

        Oh yes, that’s exactly what works with my combo fed baby! Slept 4 hour and 3hour stretches tonight, making parents happy and reasonably rested..

        • Cobalt

          Good baby!

        • demodocus

          Hooray!

        • KeeperOfTheBooks

          Awwww, what a good baby!

        • Daleth

          My twins slept 9 hours through the night when they weren’t even 4 months old. Was it the formula? If so, yay formula!

      • Mandy G

        hahaha! Truth.

  • Megan

    There is a serious amount of magical thinking going on with the lactivists.

  • Anna

    Breastfeeding is a status symbol just like “natural birth”. If you are breastfeeding it means you are wealthy enough to not have to rush to work. Wealthy enough to hire servants to do all the housework while you lay there breastfeeding. Wealthy enough to pay numerous “consultants”. Finally, if nothing works purchase another woman’s breastmilk. No matter how contaminated with gems, still better than formula. Kids grow obese stupid diabetics on formula anyway, so you have nothing to lose. Formula is for the working class. And make sure you make every formula-feeding mother feel like a monster abusing her child.

  • Amazed

    This kind of crap is what the idiots pass to each other to feel good and justified abusing other women. I am coming from Dr Amy’s page where a thing called Rebecca Lynn Rhodes thinks such abusers have the baby’s best interests in heart, they just needed to ask before manhandling the new mother. And after being called out, she had the nerve to write, “Calm your dysfuctional tits and learn to read!”

    Sorry, I don’t speak dog, else I would have told the bitch what I thought about her crap. But hey, she communicates with her baby through breastmilk, so we should all kneel to beg her understanding.

    • Cobalt

      She blocked me for posting the evidence she requested. Or maybe it was the picture of the bus that set her off, hard to say. Building herself an echo chamber, that one is.

      • Amazed

        I don’t really care about her echo chamber. I’ll laugh when the glass shards of this lovely house of hers pierce her thick skin. She offended someone with a double mastectomy because…? And she dares talk about dysfunctional tits while boasting that she breastfed despite all the hurdles. (Or was this the Angelina chick?) If her tits were so functional, she should not have met any hurdles at all.

        Monster.

  • PrimaryCareDoc

    I breastfed 2 kids. There is no way in hell that my breastmilk communicated to them that it was time to sleep. Seriously, what the fuck? Have these women ever actually lived with an infant?

    • Cobalt

      That would be a neat trick though. If it actually worked EVERYONE would be feeding breast milk. Parents of colicky babies would be paying $20 an ounce for milk from lactaters that made themselves exhausted to produce “bedtime extra” milk for profit.

      • Karen in SC

        this totally would have been discovered, synthesized and added to a special Similac formula, too.

        • Cobalt

          Shhhhimilac…Now with Hush©, special proteins patterned after the naturally occurring GTFTS protein in breast milk.

          • Zornorph

            You can accomplish the same thing by adding a shot of scotch to the formula.

          • KeeperOfTheBooks

            I’m told that when I was a baby, my pediatrician’s recommendation for a teething remedy was “pour a glass of scotch or brandy, dip a finger into it, rub it thoroughly over the kid’s gums, and drink the rest yourself.”

          • The second half of that recipe sounds especially effective!

          • Cobalt

            One of my older cousins got this treatment quite frequently as a baby, he was apparently quite a difficult infant. All was well in the end, and now it’s just a funny “back in the day” story, but it’s definitely outdated advice.

          • KeeperOfTheBooks

            Oh yeah, I am NOT suggesting anyone try that now. 😉 As you say, funny story. Though mind you, if I have another super-fussy baby and don’t breastfeed, I just may follow the self-medicating part of that advice from time to time…

          • Not necessarily. My crotchety older daughter, at 9 months, was grizzling away in her stroller when we were at a wedding, annoying everyone, so I gave her a little brandy in her bottle, hoping she’d go to sleep — but she became the life of the party after she’d drunk it [at least she stopped crying].

          • demodocus

            My grandmother accidently gave me cider that had turned when I was very young. Apparently, I slept *really* well for a *really* long time.

          • Daleth

            In contrast, my grandmother snuck a glass of champagne at a wedding when she was five, and threw up on the bridal bed.

          • demodocus

            Actually laughed out loud. Oh goodness! Her parents must have been mortified.

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      • Who?

        Aren’t these the same parents who morph into ‘the child will work out its own bedtime, let’s not impose a routine to crush the brave little spirit’ only a year or two later.

        Though if it did work I know some adults whose tea I’d be lacing with sleepy breastmilk, for which I’d cheerfully pay a premium.

  • Amy M

    Also, if the baby has an infection (how high a pathogen load is needed to transmit enough antigen via spit backwash, for the mom’s immune system to respond?), why wouldn’t the baby’s own body be making antibodies to it? Surely that would be more effective than counting on dubious passive immunity? How well are antibodies to things like colds passed through breastmilk? My impression was “not very.”

    • mythsayer

      Because the baby is basically not a fully functioning human. Babies require super mama help to turn into healthy people. It’s the MOTHER that is awesome, not the baby. Babies don’t make their own antibodies, doncha know? The super mama must make them and pass them on. That’s why breastfed babies are superior in every way.

      Oh I just had an epiphany! I never made enough breast milk to EBF because I was formula fed! That must be it! I’m still slightly broken because I wasn’t breastfed. My supply issues couldn’t have been because I had gastric bypass and thus eat fewer calories than most people…or any number of other reasons for low supply. No…now I’m sure it’s because my mother was not a super mama who gave me good antibodies (I’m sure it’s why I was overweight too…couldn’t have been my families bad metabolism genes).

      So anyway, that’s why babies don’t make their own antibodies. Only super mamas do that.

      • Cobalt

        I can counter your anecdata too easily.

        I was born prematurely to a drug addict, was never breastfed, never got sick after nearly dying a few times in early infancy (scarlet fever in a 5 month old who was 7 weeks early is not good), and I produce milk like a prize cow.

        My almost exclusively breastfed baby had 3 ear infections and strep throat his first year. My almost exclusively formula fed baby never got sick until we introduced solids and discovered his food allergies were not limited to my milk, then he was frequently ill. The ones who were combo fed and went to daycare from 6 weeks were never sick.

        The only correlated factor between my illness prone kids was high blood pressure in pregnancy, which is associated with placental issues. They also had the lowest birth weights, although still within the “normal” range. I want to see a study on the relationship between placental issues and immunity transfer, because breastfeeding certainly didn’t help my kids any.

        • Young CC Prof

          My mini-man was low birth weight due to placental insufficiency. Mostly formula fed, got a little magic mommy juice the first few weeks.

          He did not get any contagious diseases of any kind until he started daycare at 8 months. Since then, he’s had colds and one stomach bug, but nothing that required medical attention.

          Of course, I was super-careful about isolating him at first. He was not even 5 pounds, it was the middle of winter, and our region was having simultaneous outbreaks of H1N1, RSV and norovirus, and I felt zero shame about keeping him in a bubble for two months.

          Now, that is an interesting hypothesis, whether antibody transfer is reduced in the presence of placental insufficiency. Probably the best way to measure it would be blood tests?

          • Cobalt

            You ruined the test with all your evidence-based germ theory disease prevention measures!

            Seriously though, I would have done the same thing in that situation.

          • demodocus

            My full-term, 8 1/2 lb, nearly ebf (we had to supplement a bit in the first couple weeks) kid was sick 7 times in his first year with a tendency to croup. (we’re out and about a lot)

    • swbarnes2

      The thing with babies is that they likely don’t have as deep a “library” of B-cells to make antibodies. You can only make antibodies if you have a circulating B-cell with a matching receptor to whatever the antigen is. Mother is more likely to have that, especially if it’s an antigen that she’s already encountered before, in which case, she’s got B-cells primed to shoot out antibodies. (Though again, it doesn’t look like a whole lot of this is passed to the baby through breastmilk)

      • Amy M

        That’s how people (naturally, as opposed to vaccinating) build their “antibody library” though—by getting sick, and their immune systems identify the pathogen and build antibodies to it. It can take some time, but if the immune system is working right, it will happen.

        Let’s say baby gets a cold—if Mom already had that particular virus, her immune system should recognize it and fight it off, before she even knows she was exposed. In that case, she won’t get sick. I suppose she may have a temporarily increased antibody titer, and maybe some it will get into the breastmilk, but even if so, the baby is likely to just digest those antibodies before they can do any good.

        If Mom hasn’t had that particular virus, then she’s likely to come down with a cold, just like baby. Regardless of what is going on with Mom, baby’s immune system should be building antibodies, so the next time that virus goes around, baby will be all set.

  • Mel

    Before I believe in the baby spit backwash theory, I need to see that the fluid dynamics of nursing would allow baby saliva to make it past the nipple without being ejected during the next milk delivery to the baby. There is a lot of positive pressure being applied from the direction of the breast tissue towards the nipple and a tiny amount of negative pressure caused when the nipple is emptied. I am having problems visualizing how the tiny, weak vacuum that exists momentarily when a nipple is squeezed empty then released will suck in more than a few microliters of saliva which will be expelled in the next rush of milk.

    Plus, cows have a valve/sphincter near the opening of the teat that closes momentarily during that period while a valve/sphincter next to the udder opens to fill the nipple with milk. Assuming humans have something similar, the total amount of saliva that would be sucked in between the outer valve and the end of the nipple would be inconsequential and flushed when the milk is released.

    This would require doing math, though, instead of making claims about breast gland cells.

    • J.B.

      You sound like my people. Forget statistics, let’s look at fluid dynamics!

      • Mel

        To me, that’s the huge obstacle that needs to be addressed before letting the immunologists destroy the rest of the theory. Breasts and bottles have a different fluid delivery system than a small-necked plastic pop (or soda or Coke) bottle. Pretending that a suckling baby is sending saliva back into the breast through the nipple defies physics and basic common sense.

        You could actually probably test it on a bottle first. Gentian violet used to be used for treating thrush infections. The annoying side effect is that it makes the kid produce purple saliva that stains things. Give a healthy infant a small amount of gentian violet after one feeding and track the amount of gentian violet that shows up in the bottle after the next feeding. My prediction is a purple nipple, bib and baby but minimal if any purple in the milk itself even when scanned using a visible spectrometer.

        • Bombshellrisa

          No no no! You are wrecking my SPESHIL SPARKLES with your science!

        • Roadstergal

          “To me, that’s the huge obstacle that needs to be addressed before letting the immunologists destroy the rest of the theory. ”

          But I suck at fluid dynamics! 🙁

          (After the vision puns yesterday, I have to.)

        • AirPlant

          Honestly? I am 99% sure that they will just say that the receptors live in the montgomery glands if the backwash hypothesis is kicked out.

    • Roadstergal

      Even if there is backwash – the only immediate effect could be TLR-type reactions from resident innate cells – cytokine release, which would cause inflammation in the breast and would almost certainly be broken down uselessly in the baby’s gut. The generation of antibodies would require the pathogens to make their way to secondary lymphoid organs and generate antibodies, then not-terribly-useful-against-pathogen IgAs to make their way back to the milk. So you would have a danger to the mom – inflammation and/or infection – with very little potential benefit for the baby. Seems like it would be selected against, from an evolutionary standpoint – a la your cow valve.

    • Amy Tuteur, MD

      The backwash claim appears to be based on a single paper: http://m.pediatrics.aappublications.org/content/113/2/361.

      I don’t know if it has been reproduced.

      • Roadstergal

        I don’t have access to the full text, but there’s nothing in the abstract about backwash – just increase in milk duct diameter. If that’s all they’re basing it on, it’s a hop, skip, and quite a few jumps away.

        • reviewer#3

          Yup. The paper is just about measuring duct diameter in relation to milk ejection. Duct diameter increases as milk is ejected and afterwards decreases, temporarily reversing milk flow. That much seems solid.

          (from the paper: “The subsequent decrease in duct diameter after milk ejection (Fig 4)
          suggests that milk is not stored in the larger ducts close to the
          nipple but flows back into the smaller collecting ducts
          and ductules, a phenomenon we have observed as a
          reversal in flow of the echogenic fat globules within the duct. Reversal
          of milk flow has been demonstrated previously in
          vitro in the rat, mouse, guinea pig, and rabbit15 and is likely to occur in the sow.23”).

          So as per the backwash theory the reversal of milk flow may suck in baby spit? That’s, ehm, rather speculative.

  • mearcatt

    i read that article she references here when someone posted it on facebook. when i got to the part about the backwash, i thought, “you have got to be kidding me, let’s get real.” all it takes is a little common sense to think about that scenario and how unlikely it really is. does breastfeeding have benefits? yes. is it the end-all, be-all glorified gold standard some women want to claim? no.