Home » This is how a baby's immune system works - through breastfeeding and antibodies

This is how a baby's immune system works - through breastfeeding and antibodies

Hormone platelets are due to the baby's immune system being activated

Fakta om bebis immunförsvar, om antikroppar och amning. Direkt av professor i klinisk immunologi och mikrobiologi. Har nyfödda bebisar ett fungerande immunsystem eller inte? Vad gör antikropparna i bröstmjölken för nytta? Agnes Wold är professor i klinisk immunologi och mikrobiologi och en av Sveriges främsta experter på små barns immunförsvar och amningsimmunologi.

A healthy newborn has a functioning immune system

The newborn baby is born with a fully functioning immune system. It has full capacity to form immune responses to virtually all types of infections (except: enclosed bacteria). BUT since the child has had no infections, it lacks immunological memory. When you first encounter a virus you become ill. At the same time, the immune system is activated and after the infection has passed, the immune system remembers exactly how this virus looks. If you encounter this virus again, you will not be able to get sick before the immune system is activated and the virus is eliminated.

The immunological memory

Now, unfortunately, there are hundreds of different viruses and if you have not encountered a particular virus you also have no immunological memory, and become ill. Since the child is born without immunological memory, it must simply go through all the viral diseases, to develop its immunity. If there is no vaccine. It is the simple explanation as to why toddlers "are sick always" - preschool children have on average 6-8 viral infections per year), whereas we "only" have 2-4 per year in an adult. The good news is that if you have many infections that small, for example because you are in kindergarten, you get fewer infections when you start school. All because of the immunological memory!

Mothers give children antibody protection!

To compensate the newborn for the lack of immunological memory, antibodies are given by the mother during pregnancy. IgG antibodies are actively pumped through the placenta to the baby, which is therefore born with higher IgG levels in the blood than the mother has! These break down gradually, as the child begins to form its own IgG antibodies.

Calves and pigs, for example, lack this excellent system and are born without these antibodies. They die if they do not receive breast milk immediately after birth, because there is IgG that is taken up in the blood.

A virus is covered by antibodies
Masses of IgG-antibodies attack a virus in the blood. This is due to immunological memory.
Breast milk gives the child IgA antibodies which provide extra infection protection

Man is born fully-pumped with antibodies. As additional protection, the newborn receives large amounts of pre-produced IgA antibodies via breast milk. This IgA is not taken up but is kept on the mucous membranes where they prevent bacteria and viruses from entering the body. Therefore, breastfeeding protects against infections, especially sepsis (“blood poisoning”, ie bacteria in the blood) and bacterial diarrheal diseases. This is vital in poor countries, but in Sweden, blood poisoning is uncommon in healthy full-term infants and we can usually treat it with antibiotics. In principle, no infants in Sweden become ill from bacterial diarrheal diseases (Salmonella, Shigella and others). The bacterial infections that are most common in Sweden are ear infections, where breastfeeding provides some protection.

IgA antibodies protect the immune system from viruses and bacteria

While IgA in the breast milk protects against infections from viruses and bacteria, they also prevent them from coming into contact with the child's immune system and thus delay the build-up of an immunological memory. Nature prioritizes the child to grow up to be better equipped when the infections strike. They do this as soon as breastfeeding ends. Then the child has to make his own antibodies. In countries with a lot of infections and lack of clean water, this is a dangerous time when children are often suffering from severe diarrhea, so-called “weaning diarrhea”. Weaning diarrhea does not exist in a country of high hygiene standards such as Sweden. The fact that the child has received IgG from the mother (via the placenta) and IgA (via the breast milk) does not speed up the child's own production, on the contrary.

Breastfeeding offers important diarrhea protection when the water is infected

WHO recommends exclusive breastfeeding (full lactation) for four to six months. The reason is to reduce the risk of infections and malnutrition in poor countries with high infant mortality and lack of clean water and safe food. The main reason for this is that the water, the bottles and the formula there are infested with bacteria, often dangerous ones. In addition, children are often malnourished by formula feeding in poor countries with poor hygiene, both because of diarrhea and because mothers cannot afford to buy enough replacement powder and dilute it too much.

A child in a refugee camp in Uganda
In a refugee camp, like those in Uganda, it is particularly important to protect children as long as possible from infected water. This is why breastfeeding is so important.

In Sweden, where we have clean water and safe food, there are really no strong medical reasons for exclusive breastfeeding (full lactation). Replacement mixed according to the instructions on the package is good enough for the child here, although it does not contain IgA antibodies at all. Just so you know, since olden times you have probably chewed food and put it in the child's mouth. Many studies show that children in all countries and at all times received tasting portions of one thing or the other in parallel with breastfeeding.

You can read more about strengthening the child's immune system by sucking on their pacifiers.

29 thoughts on “Så fungerar en bebis immunförsvar – om amning och antikroppar”

  1. As for the breastfeeding's advantages and disadvantages, I am still shocked at how the medical services in the area (bb & neonatal) have completely lost judgment (including the medical) and do not see any possible disadvantages of breastfeeding.
    I have type 1 diabetes and got pregnancy poisoning with the first child and was cut in v.36. Was very bad because the blood pressure only continued to rise and was on bb for 2 v. Although I took blood pressure lowering (first beta blocker) and my blood sugar disturbed dived at minimum stress (ended up in coma on 2 occasions during my bb time) I was encouraged to breastfeed. The daughter, however, was not so interested and she was also bottle-fed to keep the weight because she was a little early. They came empty and checked the daughter's blood pressure to see that she was not affected by blood pressure lowering. When I then got ACE inhibitors, the pediatrician at bb was a little more cautious but urged me to pump and toss the milk; because it could happen that blood pressure would stabilize, the ACE inhibitor would be exhibited and then I could continue breastfeeding. I printed with ACE inhibitors and a pump! I never used the pump and the ACE inhibitor remained.

    4 years later I was cut with my second child. Now after a major "risk pregnancy"; when the kidneys were already loaded and my ACE inhibitors were exhibited during pregnancy. The daughter had low blood sugar and ended up in neo for a few days. I get back ACE inhibitors + other blood pressure lowering. I am again asked to breastfeed, get a pump and they want me to give it to her via the probe. When I ask if it is so wise about ACE inhibitors (and other blood pressure lowering), when this 4 years earlier was said to affect the children and that it was forbidden when she was in the stomach I get an answer; "You have to give her a little. It is so good with breast milk and we keep track of her blood pressure ”. This was a neo-doctor's word. When she is discharged from neo, I ask another neo-doctor again and point out that when breastfeeding it is difficult to know how much she gets in, I should just pump and measure the quantities (?) That say: “breastfeed / give so a lot of breast milk you can (without specifying where the limit goes) but you have to come back before you are printed from bb and we check her blood pressure ”. Can a neo-doctor be wrong, I think. Printed a day later from bb with pump. Just like all other parents, you want to do what is best for your children, you have also been at risk of pregnancy and yourself have illnesses you want to protect your children from, so you become extremely sensitive to similar breastfeeding requests. Then I am still a used care recipient, can screen and relate critically to information.

    Only a month later, when I can think clearly again, I meet the specialist maternal care, my kidney doctor and diabetes doctor. Everyone says: “You should stop breastfeeding / pumping only compensation. So good is not breast milk that it outweighs any risks due to blood pressure lowering and it is not as good if your blood sugar drops rapidly due to breastfeeding. "
    Unfortunately, I do not think my story is unique and now we still talk about bb and neo at Sweden's leading and most research-oriented university hospital and about a patient (electricity rather 2) where the contraindication for breastfeeding was very obvious.

  2. I think there has been too much talk about breastfeeding benefits and not enough talk about breastfeeding disadvantages. There is no balance in the discussion and thus the fight arises. It has not been allowed to say anything negative about breastfeeding for a very long time. It's only good that in recent years, women have started raising their voices and telling them what they have been up to and saying that there is actually a back side to breastfeeding.

    It is not realistic to only talk about the medical benefits of breastfeeding and total closure because breastfeeding causes some women and children extremely great suffering in the form of pain, bleeding nipples, breast infections, fungal infections, poor weight gain with associated anxiety, depression, etc. Not to mention being 100% burdened with the task of feeding the child and what it can mean for one's freedom and well-being. These things are important! Just because we are women, we should not only face these disadvantages but beyond. In what other context do you only take into account the advantages and the total disregard for disadvantages? In everything else we do, you look at the pros and cons and make a decision afterwards. But with breastfeeding we are expected to buy straight because there is evidence of medical benefits (however small) and therefore we MUST breastfeed our children (however much it costs us).

    And the big question that remains unanswered - is it worth it? Are the benefits of breastfeeding in Sweden greater than the suffering it has caused to all these thousands of women and children? Is it ethically justifiable that Sweden has a breastfeeding policy that only advocates breastfeeding when it can at the same time cause so much suffering for such small benefits?

    The truth is that the differences are very small. Some women would feel cheated if they really understood how small the differences were. Some women have put so much personal time and energy into breastfeeding that they do not want to feel that it has been too little. Others have not experienced any major disadvantages and do not understand what the problem is. And for some women, breastfeeding has become a path to personal salvation.

    In any case, I think it's about time that the discussion about breastfeeding was characterized by humility and was more about "what to do if you want to breastfeed" than "all mothers should breastfeed". Because one constantly talks about the benefits of breastfeeding without any counterbalance, it is not about informed choice, but about breastfeeding.

    If you want to read more on this topic, please read Hanna Rosin's article in The Atlantic from 2009:

    Andrea Nord

  3. I think the fairytale blog is excellent, I follow it and have even thought about it before. Lin who writes that blog also tends to be reasonably nuanced when presenting new findings. The breastfeeding blog, on the other hand, I do not really work as a scientific basis, I think it actually varies a lot in quality. By references to medical claims, I mean references to scientific articles or scientific compilations of studies. On the other hand, it is excellent to refer to blogs with a question if it is correct, so we can sort it out sometimes if we have time (or quickly say yes or no if it is easy, which knowledge background for breastfeeding advice never is).

  4. I can only agree that Swedish moms should have every opportunity to choose if and to what extent they want bottled foods or breastfeeding! We have such good conditions that both alternatives are "good enough". However, I find it strange that Agnes Wold is so confident that it can not have any health benefits even in countries with clean water and good economy to give the baby breast milk! Do I misinterpret the text? As I read the text it sounds like there is no medical reason at all to breastfeed in the western world.
    Do we really know enough to say that? Is it exactly the same to give compensation as breast milk?
    I do not know what it means in practice for children to e.g. get antibodies and stem cells via breast milk, but I have a hard time believing it doesn't have any significance at least at the population level !?
    Of course, this does not mean that these ingredients need to motivate more mothers to breastfeed - especially if the mother is not happy or does not feel good about breastfeeding! But to say just that it does not matter, I think that is exaggerated the other way. (is that going to balance the debate?)
    The breast milk is actually the herb. Would it be strange if it had no benefits - is it not at all trying to emulate breast milk and constantly come up with improvements to the replacement products !? Isn't it needed anymore?

    1. Thus. Breastfeeding is the way nature has developed for mammals to raise their young until they can eat themselves. Therefore, breast milk contains the nutrients the child needs. Breastfeeding “exclusively”, ie not giving anything else besides breast milk, is something that was launched in the 1980s. This idea was based on studies that children in poor countries were polluted with water and fed with dangerous bacteria (Shigella, Campylobacter, Salmonella). Since it was possible to show that children did not need extra water when it was hot (which was usual to give in warm countries without access to clean water), they decided: Only breast milk is best. At that time (the 1980s) this applied to the child's first 4 months (later it was extended to 6 months). This was and is the only reason to call for complete cure, that is, to give nothing but breast milk. In countries like Sweden, the Council on Whelming is completely irrelevant, since we have clean water and clean food.

      Then breastfeeding is inherently infection prevention. This is vital in countries where infants are affected by dangerous infections and child mortality is high. In Sweden, it is of minor importance, as the dangerous infections that breastfeeding protects against (blood poisoning and bacterial diarrhea) are extremely uncommon.

      Another question is whether breastfeeding is “better” from a nutritional point of view than other breeding. The question is wrong. No one has claimed that a mother who wants and can breastfeed should not. The question is whether one who does not want / can / can breastfeed gives their children a noticeably worse start in life. The answer to the question is: No. We cannot measure any significant differences in health between children who have received breast milk compensation, compared to those who are breastfeeding, in a country like Sweden. From a scientific point of view, one can never say that a difference does not exist. But you can say that the difference, if it exists, is very small. So small that it has no practical significance. This is the case with breastfeeding visavi "bottle". No one can prove that breastfeeding is not a little, a little better (but on the other hand, you can also not prove that breastfeeding is not a little, a little worse). But it can be proved that the differences in health between children born on breast milk or bottle milk are insignificant. In a country like Sweden.

      It is peculiar that you are so extremely careful when it comes to breastfeeding that you have to "follow nature". This is how you never reason otherwise. It is unnatural to live in warm, comfortable houses, wear designer clothes, drive a car, read books, wear glasses, shave, use deodorant, fix your teeth, use anesthesia at your dentist….

      I simply think it is a shame that so much importance is attached to a factor that has such a limited significance for children's health, as if it was breastfeeding and for how long. In Sweden, that is. One can compare with how little importance one attaches to whether fathers take their share of parental leave, a factor that is certainly of much greater importance for the child's future health.

    2. Hi Agnes,

      An advantage of breastfeeding that is not dictated here is if the children get so sick that they can neither eat nor drink. Then at least they can breastfeed. My son got so terribly sick when he was 18 months that he didn't eat or drink in two weeks. The only reason he never had to go to hospital and get drip was because I breastfed him. Another good reason is that they cannot be constipated. My son didn't poop for ten days when he was fully 5 months old baby. The only reason I did not have to worry was because he did not eat or drink any of the abrasive powder solution so the breast milk was only absorbed by the body. These two uneasy moments never became serious but could have been if I had given him a bottle of milk.

  5. I think it is sad that nursing cannot just admit that there are actually 2 approved ways to feed an infant. Only propagating for one way causes problems and suffering for those women who are not able to breastfeed or who do not like breastfeeding (and we are quite many). Also, I am tired of the fact that breastfeeding benefits have been raised to the skies so people think the differences are huge when in reality these differences are very small. This means that some people feel justified in insulting women who for various reasons do not breastfeed, or it causes some women to fight bloody with their breastfeeding at a very large personal cost. As Agnes Wold mentioned above, there is no reason to try to nudge all women into breastfeeding when compensation is such a good alternative. I am tired of the bottle-hostile climate that is a result of the breast milk cult that originated in the early 1970s.

    1. If several bottle-feeding moms now feel that we "take the fight", not everyone may have always managed to talk about breastfeeding benefits without conveying guilt. Although that wasn't the point.

      It says something about the feelings that exist both in breastfeeding activists and bottle activists that both have a history writing where today they have to "fight" for it to be wrong in the 70s. My God, I'm an 80s talist! The 70's is quite a long time ago. Can't we just sympathize with each other's experiences of feeding experiences?

      And anyone who wants to tell you that breastfeeding has more medical benefits in rich countries with good hygiene than infection protection for the child and weight loss, menopause and reduction of breast cancer risk at group level with the mother are asked to provide scientific references.

  6. Agnes and Cecilia you are so good! Thank you for taking the fight and going to the bottom with cross-claims and risk-assessments.


    1. I just think it's so sad and shame it should be a fight. Why can't all of us who are interested in infants and their parents spend our time helping them with what the parents want and the babies need help with?

  7. Only ignorance of the cure can speak for advocates: breastfeeding does not have strong medical benefits.
    The cure protects the child's dental health,
    Ovarian & breast cancer in mother.
    Oxytocin has a calming effect, especially valuable in depressed mothers. Mothers who may find it more difficult to interpret the child's signals will, with the help of breastfeeding, have a natural bond / connection with the child. About this, Katherine Kendall Tacket has researched and written about.
    Emotional vital to both mother and child.
    Breast milk has a laxative effect in the child and constipation is uncommon.
    The drinking water is not as pure as one would like to think if you do not buy bottled spring water.
    Drug residues, nitrogen that cannot be filtered out, are found in the tap water.
    Bottles and pacifiers in all honor but full-breastfeeding with breast milk have superior physiological and psychological effects on mother & child.

  8. When did the WHO change its breastfeeding recommendation? As far as I know and read, it is 6 months of full paralysis and then sub paralysis for 2 years or longer that is advocated.

    1. WHO has not changed its recommendations. However, the National Food Agency has changed its recommendations that flavor portions can be introduced from the age of 4 months.

  9. Well, that is, now it is not about agreeing or disagreeing, but whether there are any studies that show a statistical difference in any significant medical parameter, between a paralyzed or fully paralyzed Swedish child. So if there is any difference between a 3-4 month child who receives 50% breast milk and 50% other food, respectively a child of the same age who receives 100% breast milk? If Swedish authorities are to go out and state that it is important to cure up to a certain age, there must be evidence.

    After all, it was very nice that your son did not get the flu! But that cannot be explained by the fact that you had to make antibodies against this particular virus, because it takes a couple of weeks and then he was already exposed to the virus. I also can't explain why, but there are a lot of things that no one can explain with today's knowledge.

  10. I was also somewhat surprised at the view that breastfeeding in a country like Sweden would have no particular medical causes. However, I think that if people do not want to breastfeed, it is much better with satisfied parents than forced breastfeeding. Refers to the review of knowledge published in the medical journal, where it is mentioned that WHO has now changed its recommendations for exclusive breastfeeding to six months.


    1. That being said, this is not an opinion, but a finding that there is no evidence that full-paralysis would have medical benefits compared to sub-paralysis in a country like Sweden. Since Sweden signed the WHO Code, we promised to advocate for breastfeeding and that health care professionals should at all times emphasize the benefits of breastfeeding. I have written to the head of the National Board of Health and Welfare and pointed out the illogical and, in my opinion (here's an opinion!) Illegal not to tell the truth (there are of course cases when breastfeeding is not the best, for example if the mother eats cell toxins and we can not have Swedish laws where we talk about what healthcare professionals should say in medically complicated questions).

      After much curvature in the question from powerful pediatricians, I now find it satisfying that it says this in the article you refer to:
      "In countries with high infection pressure, there is strong support that just 6 months of exclusive breastfeeding reduces the risk of children being infected with certain infections, which is the basis for WHO's global recommendation." So, as I said, WHO's recommendation is founded themselves EXCLUSIVELY on the situation in developing countries and they want Swedish women to heal for 4-6 months in solidarity with them.

      A quiet wonder: I think solidarity is excellent. However, we cannot do that all Swedish men are allowed to reduce their caloric intake by 50% and only drive one week a month. Imagine what good it would be for the world.

    2. Thanks for the reply. But if I read on WHO's website, it is not at all based solely on the situation in developing countries, (where did you see it? What I see is studies from all over the world), on the other hand, there is strong support for breastfeeding care there compared to it eg Sweden , where gastroenteritis is not life threatening in the same way. In the source to which the Medical magazine also refers, I find this, which applies here as much as everywhere:
      “Adults who were breastfed as babies often have lower blood pressure and lower cholesterol, as well as lower rates of overweight, obesity and type-2 diabetes. Breastfeeding also contributes to the health and well-being of mothers; it reduces the risk of ovarian and breast cancer ”

      Solidarity is a beautiful word but what it has to do with the thing I do not understand. As for calories, I'm too fond of mouthing them but I like the idea of driving haha!

    3. Without even reading the studies that should have shown that breastfeeding children later in life suffer less from cardiovascular disease, diabetes, etc. I just want to point out something that is important to remember when interpreting research results (now I do not specifically address you Nina, but to all readers who do not have their own research experience).
      Just because two factors occur simultaneously (eg breastfeeding as a child and lower BMI as an adult) does not mean that one depends on the other. That is, it does not have to mean that there is a causal relationship.
      When studying long-term effects of breastfeeding it becomes extra difficult to know what depends on what and why. For example, it is known that highly educated mothers (as a group) are breastfeeding their children to a greater extent, and breastfeeding them longer. The same group of mothers also more often have stable living conditions, smoke less frequently, weigh less, and eat healthier foods, compared to low-educated mothers (as a group). Factors that have the greatest impact on children's health in the long term. Therefore, it is extremely difficult to isolate a single phenomenon, such as breastfeeding, and to say that it is associated with the risk of developing cardiovascular disease later on. Because humans are not knockout mice living under standardized, strictly controlled conditions. It is not possible to fully adjust for all environmental factors.

    4. I am reading this properly. That is, produce the studies on which the recommendations are based. Will return with posts when I'm done.

  11. Read somewhere that it is good for the child (immune system or intestinal flora) to get the mother's stools during childbirth. Is this correct?

    1. Well, hard to say what is "good". Although I have been researching intestinal flora for 30 years, I cannot give a simple answer to that question. I would say this: Bacteria are not very kind creatures. But we have developed an immune system during our evolution that is adapted to the amount of bacteria (and viruses and parasites) we have been exposed to for a million years. If we now get in drastically much smaller bacteria and fewer different types of bacteria, and get fewer infections, then there is a risk that our immune system starts to find its own host and react to harmless things. Then you get allergies.

      Funny enough, I do not know that anyone investigated about births where the mother poop on the child leads to less allergies than if this does not happen.

  12. Thank you Cecilia (and Lina) for a very educational blog, and thank you Agnes for this informative post!
    Agnes writes "The good news is that if you have many infections that are small, for example because you are in kindergarten, you get fewer infections when you start school."
    I wonder if you might be able to help me, I have previously tried to find sources for the specific correlation at the individual level between the extent of infections in the preschool age and the school age, without any particular success (certainly says more about my ability to search than anything else). Of course, I can buy the mechanism as it is described, but it would be interesting to see what has been shown and how. Do you have any reading tips or maybe better search terms than I could come up with? Thanks in advance!
    / Intern

  13. I can add that it feels as if the women are not respected by the health care when they first say that they do not want to breastfeed and then they hear from the midwife that the colostrum is something totally overweight that a child cannot be without. Many of these women are angry that they were pressured to start breastfeeding for the sake of colostrum, even though they did not want to.

    1. Of course you have to decide for yourself if and how long and how often and how much to breastfeed. The law states that patients (and this includes healthy mothers who have given birth) must be treated with respect and have the right to self-determination.

  14. Thank you for this guest blog! Very well written! There are several members of my Facebook group “The Right to Choose Bottle Feeding” who have sometimes worried that they have not given their children raw milk. It's an argument that some midwives use when moms say they don't want to breastfeed "But please, give the baby only colostrum anyway." I've told them that babies are born with antibodies they get from their mother directly via the umbilical cord. It would be good if you could tell a little more about the importance of colostrum for Swedish children so that women can make an informed choice about whether or not to give colostrum when they are not thinking about breastfeeding.

    1. Okay, what to say about colostrum? It is the first milk. It contains less casein and is therefore not white, but looks more like blood plasma. It contains more IgA than the ripe milk, but on the other hand there is so little colostrum, so the amount of IgA the child gets per day is about the same. There is nothing mysterious about colostrum, it is just a little more concentrated than the ripe milk in terms of certain factors, and has less of others. There are also more immune cells in the colostrum, which it can now have significance.

      In many cultures, the colostrum is considered unfit (because it looks like it was) and discards it. From what I understand from your post, we have apparently today encountered a minor cult of the same body fluid. Strange!

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