Thanks, **Pullet **(and now I know where you got your name!). Although I have to agree, I wonder how applicable the animal studies are to humans. I did find that study on gut closure you cite, but I’ve also always heard that it’s important to delay certain foods, especially cow’s milk, until about a year because the gut is open enough to allow the proteins through intact, and that heightens the risk of sensitization and allergy.
I’m also wondering perhaps if there are other factors that help fight disease that are not immunoglobulins per se, and might be absorbed even after they cease to be? (I’m totally out of my depth and speculating, I admit). IIRC, there are studies at least in developing countries that there are significant mortality rate differences between older children who still nurse and those who have weaned, which is a big part of the reason the WHO recommends at least two years of nursing. So that makes me think there has got to be something passing from mother to child.
Similarly, the idea that the disease-fighting benefits of breast milk are done at 2 days doesn’t ring true when babies who nurse exclusively seem to be generally healthier and better able to recover from illness.
It all definitely warrants more research. This whole field of inquiry is quite new after all. I’m (slowly) working toward becoming a lactation consultant, and my mentor said, “There aren’t many jobs where you can go to a conference and hear the people who created the profession speak in person.”
Thanks to you who have given virtual hugs and thanks for this thread. Even being the opinonated bitch I am, posting this did bring a certain lurking fear of people going, “Oh my OG, she’s a freak, SHUN her!” So it’s nice to get some kudos, as well as the curious or doubtful responses. And thanks also to those who have been curious or doubtful, but very respectful too!
Hopefully I won’t get modsmacked for resurrecting this thread, but I needed time to do the research for this essay, which means I had to wait for finals to be good and over.
The studies are everywhere, but you often need access to a university’s library to get at them. Researchers aren’t in the habit of posting their whole work on the internet at large.
I’m looking now to see if there’s a good textbook I can point you towards, since that would be easier to lay hands on and would be a condensation of the research literature. The trick is finding something that’s written at a high enough level to even get into this kind of topic while, at the same time, not having so much terminology that it’s incomprehensible to anyone but the experts. Hopefully more news to follow.
I found this in the ACTA Paediatrica Scandinavica supplement 271 from 1978 “Antimicrobial Factors in Human Milk” by D.B.L. McClellan and Joan McGrath. In it, they analyzed the milk from humans for as long as 200 days of lactation.
Quote:* "IgA concentration showed a distinctive pattern, falling very rapidly over the first 4 days […] with a much slower, sustained decline in later samples. […] The initial samples [of IgM] contained concentrations similar to those in normal serum (blood of the mother), but the levels fell rapidly to approximately 10% of serum values and IgM was undetectable in the late samples
[…]
The mean IgG concentration was never greater than 3% of the mean normal serum concentration and fell below the lowest standard of the assay in the late samples. The mean intake never exceeded 100mg/day."
*
If you like, I can scan and post the pretty graphs they made. All of them show the antibody factors of milk dropping rapidly as lactation goes on. And they only looked at the first 200 days of milk production.
Your link is broken. And I don’t understand what you are trying to say because your sentence seems to contradict itself.
Besides, what I said earlier is that the level of antibody drops off, not that it goes to absolute zero.
You say that everything you can find contradicts what I have found. Can you provide me with links?
It’s not exactly fair for both of your to counter my cited statements with "something you heard/read’ somewhere.
Zoe, I believe the research you are talking about deals with reduced rates of breast cancer in women who have breastfed. I don’t see how this proves that the milk itself is reducing cancer, as opposed to the process of lactation providing some cellular resistance to mutation or virus or whichever is the most common cause of mammary carcinoma. Unless you can point me towards a study that demonstrates otherwise, of course. Unauthorized Cinnamon, everything I am finding on allergies and exposure to cow’s milk is saying that, if the baby is going to be allergic, it will be allergic no mater what. Delaying exposure to cow’s milk seems to delay when the allergy sets in, but doesn’t prevent it. Gut closure against the whole absorption of proteins has been well studied for many decades. Proteins passing into the blood intact is simply not the way that infants more than a day of age are being exposed to allergens. I’ll scan and post studies if you ask. This post is long enough and I have a feeling it will sink into the abyss of the boards anyway.
That study I quoted above also looked at the levels of Lysozyme and Lactoferrin, two enzymes who both work to make milk an uncomfortable place for bacteria. Lysozyme works by lysing, or exploding, the bacteria cells, while lactoferrin binds up iron so the bacteria can’t have it, so they die from malnutrition. The main function of these enzymes is to keep the mother from getting mastitis, but some researchers think that they might also help keep bacterial counts inside the intestines of the infant lower. However, I couldn’t find any good studies proving this. At any rate, the amount of these enzymes in the milk drops off over the course of lactation, just like the antibodies, and, like the antibodies, what effect they might have would only be inside the gut of the infant, not in the blood stream, and would depend on exactly how much enzyme survived the digestive juices in the stomach.
Similarly, there are theories that the antibodies, what little there are, may have some effect inside the intestine of the infant, but not in the blood stream. But, this has not been well demonstrated. Also, neither lactoferrin, lysozyme, nor the antibodies would have any effect on viruses.
Can you point me towards some studies that demonstrate this difference in mortality rate being due to increased immunological factors from the milk, and not simply because infants who breastfeed are getting better nutrition? I mean, if the mothers are getting good enough nutrition themselves to even be providing milk, isn’t there a good chance that the family has the means to provide overall good nutrition, hygene and stability for their toddler, any of which would increase the survivability of the baby?
Everything I find agrees with you both; Babies who are breastfed are, on the whole, healthier. But, we don’t know why yet. And our persistent ignorance is not for lack of trying. Experts have looked at the antibodies and enzymes in milk and have decided that they aren’t the reason, or at least not the main reason. That’s why theories like the “breastfed babies are fed upright so they get fewer ear infections” mentioned up thread have traction. We’ve discounted the easy ideas and so have to start looking at more complex ones. In all likelihood, healthier breastfed babies probably result from a lot of different reasons, some of which we may not have even thought of yet.
I didn’t come in here with the intention to threadshit, and I hope my posts haven’t been taken that way. In the end, the message is the same: Feeding from the breast is better. I just didn’t want mothers who don’t nurse their toddlers to feel like they were depriving them of medicine, because milk is not medicine.
Here’s another article supporting pullet’s contentions, but also pointing out that the antibodies in milk do have a function, even though they don’t make it to the bloodstream.
Also, I don’t have the means to look up this article (although it sounds like pullet does, so maybe he will be kind enough to summarize for us), but former poster hedra claims (on another board we both belong to) that the timing of gut closure varies depending on feeding method: J Pediatr Gastroenterol Nutr. 1995 Nov;21(4):383-6. Intestinal permeability changes during the first month: effect of natural versus artificial feeding. Catassi C, Bonucci A, Coppa GV, Carlucci A, Giorgi PL. We’re still talking within a month, and it’s sooner, not later, for breastfed babies, so this isn’t going to make much difference in the extended nursing debate, but it’s still interesting.
My mom breastfed my little brother until he was five. She was a member of the La Leche League, and this was around 1980 or so. After a certain age (not sure when) she mainly nursed him at night as a comfort thing. It never struck me as odd, but looking back it is kind of funny to think of my brother saying, “Mommy, I wanna nunie.”
Naturally, now that he’s a grown man we like to tease him about it, but that’s only because we are siblings and that’s what siblings do. We don’t tease our mom about it because it was completely normal to us at that time, and I don’t feel like it was really all that weird (despite popular opinion).