Submitted by molllymaybe t3_y6z25l in askscience
Since we have a whole plethora of microorganisms living in our gut system, I was wondering how early/how that is developed in humans? Does it develop while we’re in the womb and if so, how? I hope this question makes sense and thanks in advance!!
>Welcome to biological life; it's disgusting, but it works.
I'd argue it's only disgusting because we choose to see it that way. Biological life is an amazing and diverse work of machinery.
You are correct, of course. But the disgust is also part of our wiring. We evolved to find such things disgusting, because in most cases, slimy, poopy, bloody situations are vectors for disease transmission. It serves survival to find all such sensations and appearances disgusting.
Which is why we also have a circuit for shutting it down during things like sex. The same person who is disgusted by slime and goop and oozing will, if aroused enough, find all of those things attractive temporarily.
It's amazing machinery, and amazing evolutionary programming, but - also really grotesque.
Though, as stated, I only find it so because my meat evolved to keep me from messing with it in most cases.
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>Gut bacteria are crawling all over the anal/genital region all the time, as well.
Serious question... for those of us who frequently go down on our partner, do we have a healthier gut biome (or at least one that more closely resembles our partners)?
You know asking for a friend of course...
I remember reading somewhere that spouses tend to have a similar gut microbione.
I think that may be due to prolonged exposure. Because our bodies attempt to attain homeostasis constantly, our bugs will naturally get rid of a small introduction to something foreign. But if it's a constant input of something foreign it attempts to reach an equilibrium without having to constantly rid itself of foreign bugs.
Short answer - no. Your individual gut biome 'signature' is established in early childhood and as long as you are healthy it doesn't vary much regardless of where you stick your tongue.
Source?
At face value, this implies that probiotics are useless.
Proof of the efficacy of probiotics is pretty mixed. There's only marginal evidence they might be beneficial when taking antibiotics. Many of the bacteria in probiotics fail to establish in the gut. Fecal transplants, on the other hand, show a lot of effectiveness.
Probiotics are not used to establish a healthy flora, but a flora, that wont hurt you.
If there is nothing and intensines are free for colonization you are asking yeast or different bacteria like clostridium to take a hold there.
If it is colonized already, this is harder.
Probiotics may have some moderate benefit if your gut microbiome has been peturbed e.g. you are taking antibiotcs or you've has diarrhea. But if you're healthy then there's not a lot of confirmed benefits.
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I could be wrong, but aren't most supplements useless?
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Probiotics aren't entirely useless. However, if you look there are usually only a couple of type of bacteria in them.
There are hundreds, if not more, different type of bacteria in your gut.
It's not harmful, but unless you've been on some hardcore antibiotics , it's not that helpful either.
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Yeh, its more like it doesn’t change because you already have the same microbiome as your partner.
That’s not true at all…
Antibiotics are a great example, they kill of a huge amount of bacteria a leave behind a micro biome with significantly less diversity. Then through eating some new bacteria can colonize.
In peritoneal dialysis, it is common practice in my region to have patients taking any oral/IV/IP abx to take probiotics to prevent colonization of yeast in the peritoneal cavity.
It should be common everywhere.
Add also clostridium difficile, usually older patients.
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Nah. That doesn't make any sense Why should the first things in your gut be the best?
A course of antibiotics will hammer the bacteria, a different set will surely grow back. Over the course of, call it a year, you have to encounter critters that're better suited than the last lot.
Also, faecal transplants.
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Not likely. Your gut microbe actively defend their "territory" in the gut. They are not going to give up such valuable real estate without a fight. This is called microbial antagonism. So you may ingest all sorts of bacteria be it sex or just eating, if you are healthy you already have microbes in place and whatever you are ingesting basically can't easily take hold because of this. Not saying it can't happen at all, it is just that the microbes are not just "passively" there, they are there and intend to stay. That involves various biological processes they use to make sure they do. One is to simply take up all the real estate so something coming through has no space to colonize.
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Our stomach invests quiet a lot of effort into killing any living cells that enter it. Very little will survive to the gut. Infants are likely to have a pretty weak line of defense.
All of this. This is why cesarian births aren't optimal for the overall health of the baby. I did read somewhere about how one doctor was trying to remedy that situation by doing a quick swipe of birthing muck inside newborn nostrils and mouths when they are born cesarean. I don't remember if anything came of that though or if he proceeded to a testing phase etc.
Yeah, it would seem that issues with cesarian births that are 'sterility-related' (i.e. skin/oral/gut microbiome composition) should be relatively easy to fix with artificial application of the relevant mucus/fluids/culture from the mother.
But as is the case with much of biology and medicine it may also turn out to be much more complicated than simply applying some vaginal mucus, placenta, or what-have-you.
Yeah it's...not well-supported by the literature. This suggests it's apparently more complicated than just the actual passage through the birth canal, too
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I get what you're saying, but cesarean births are usually performed when the probable alternative is a stillbirth, in which case it is giving the optimal outcome.
Surgical deliveries are being shown to alter the development of the microbiome and may well be the explanation for the rise of autoimmune dysfunction, allergies, and food sensitivities.
In that case are C-section babies at a disadvantage somehow? I feel like that would be easily documented as well.
It's a fact, yeah.
But it's not the passage through the vaginal canal that's important, it's the antibiotics that the mother gets.
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It is. Fortunately, bacteria are everywhere, and people are messy and sloppy. One way or another, everyone develops a gut biome.
It's just that the best biome comes from your mother, and establishes early. There is speculation that some issues - including obesity - are strongly related to the specific gut biome people gain in early childhood.
Some morbidly obese people might - I stress might, it hasn't been solidly proved yet - could be victims of, well, not enough poop all over them when they were born. They picked up a gut biome from the environment after, and it may not do the right job - goes the theory.
Cesarian sections bypass this transfer of potentially life-saving bacterium to the child.
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I was taught that same thing. Mammals are born with a "sterile" intestinal tract that will gather bacteria from the world around it shortly after birth. Can't claim any knowledge about baby guts, but with puppies, we give them a dose of probiotics then put them on their dam for first milk. We know bad stuff gets in there but we want our good stuff to get their first and start populating the tract. Interesting stuff on this sub.
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Yep and there's actually research showing a difference in babies born vaginally vs via c section. Some babies born by c section are actually swabbed with vaginal mucus after delivery to help establish a healthy microbiome.
This is really fascinating thank you! I didn’t know that overly-sterile births could potentially be harmful, that’s really interesting
We are not just one being - we are a colony creature. We live only because of other animals that live in, on, and all over us. We couldn't digest our food without our symbiotic gut bacteria. We couldn't avoid being killed by fungus if not for the bacteria on our skin that constantly eats it. We couldn't avoid blindness, save for the microscopic insects that live in our eyelashes - kill them off, and people tend to lose their eyesight.
We are a world, and entire populations live and die upon, and within us. Our biome, our personal ecosystem sustains and protects us.
Yes, sometimes it can all go horribly wrong, when one faction gains an upper hand - that is true. Or if one of the species on us gets into somewhere it doesn't belong, such as if bacteria on the outside manages to get inside. But, in a very real way, we are not one creature.
If we were rendered entirely 'clean', with no cells or organisms upon or inside us of any kind, only human cells, only us, we would die from multiple reasons. It would be a race to see what failed first.
We are many.
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Idk about humans but I study cattle and their immune system is cool. They’re born with essentially no immune system. They get passive immunity from moms colostrum (first thick milk produced after birth) in the form of antibodies/proteins. This passive immunity goes out after about 1-2 weeks and whatever bacteria that happens to be around starts populating the gut. Calves usually get really sick with “scours” when this happens. Their active immunity is kicking in! Then their rumen continues to get populated with microbiota as they eat forage. They’ve got a complex micro biome because they digest/ferment lots of plant material and we are still learning about how this micro biome develops in early life! It’s part of my PhD research :)
It is mostly devoid of bacteria while in the womb, or the mother would be having a far worse time. A bacterial infection within a fetus that has no immune system, and where the mother's immune system cannot reach, but is still contained inside the mother's body? Talk about a nightmare.
So, the human microbiome is instantiated at the time of birth, while the baby is sliding out of the birth canal and vagina. They aren't exactly sterile, especially when outlets that shouldn't be leaking start leaking.
The next major source of inoculation is via breastfeeding. Breastmilk itself isn't sterile, and neither is the delivery vessel. All that ends up passing right though the stomach and lands within the intestines.
And you pick up other critters while eating, breathing, and generally living. They are everywhere, after all.
I would like to add that our personal microbiome is not the same throughout our life. It changes according to what we eat, physical exercise, the environment in which we live in... ect. Also we share a similar microbiome with the people around us most of the time (es. cohabitants). So, after our birth, we receive a first colonization of bacteria that it will change with time.
> while the baby is sliding out of the birth canal and vagina. They aren't exactly sterile, especially when outlets that shouldn't be leaking start leaking.
They absolutely SHOULD be “leaking” during childbirth, by the way. I suppose you meant that they don’t normally leak when not performing certain special tasks.
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I’ve read about an idea that some doctors advocate for caesarean births - since the baby doesn’t get that journey out the birth canal, they put a cloth up the mother’s vagina for a while, then rub that cloth over the baby’s face to inoculate it with that biome. As far as I know this isn’t common, but it’s an interesting idea.
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If a baby is born via c-section and then is bottle fed formula are they more likely to have stomach problems?
Not neceserally: they still are in skin contact with the parents, and babies put EVERYTHING into their mouth, giving ample opportunities for microbes to start living in their guts.
Microbes are everywhere and our body has multiple "built-in" systems which help the good microbes to profalite. The gut microbiome is an ecosystem on its own, constantly changing and growing as our habits, environment, stress level, eating habits (and so much more) change while our immune system works hard to keep them in check and make sure they don't do anything which they shouldn't do.
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Also somewhat important to note, that it still takes time to fully flourish and coat the GI system. This is why it is contraindicated for infants less than 1 year of age be fed honey. Honey isn't pasturized and there can still be clostridium bacteria which can attach to young GI systems causing floppy baby syndrome.
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Just to note that the uterus is not sterile - it contains its own flora, although it's not clear that this can cross the amniotic sac into the fetus's digestive tract.
makes sense, it's partially open to the world for a few days every month, after all.
Most bacteria comes from the breast milk. Not from blood during birth. And most women poop way before birth, and hospitals don't let them eat much to avoid poop on the newborn. https://www.frontiersin.org/articles/10.3389/fped.2019.00047/full
Its to lower the risk of aspiration (vomit being inhaled - can cause pneumonia and even death) if the woman needs a c-section than poop on the baby. When laying flat or being put under anaesthetic there's a higher risk of aspiration for pregnant woman than the regular person as pregnancy hormones relax everything, including the sphincter keeping food in the stomach. It's the same idea as being fasted before surgery. I'm a nurse and studying to be a midwife and to my knowledge, it's never had anything to do with pooping on the baby. I do remember while at uni seeing and reading some studies investigating the role of vaginal flora on inoculating babies' gut biomes, so it is believed to contribute, but breast milk absolutely does provide a good amount as well, you're right.
Technically a chemical pneumonitis rather than a pneumonia, but yes mostly what you said.
Don't they make you eat if your blood sugar drops?
They can have a liquids tray: a warm thin soup broth, unsweetened juice, popsicles, jello.
Sure, or for longer labors. But my point was there isn't commonly a lot of poop involved in hospital birth. Certainly not enough to create the gut biome.
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This is a really cool read thank you!
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If you’re interested in reading a really cool book about micobiomes, the book ‘I Contain Multitudes’ by Ed Yong is great. It answers this question in a great and easy to understand way. It was a fascinating read.
I will definitely check this out thank you! I’ve been looking for interesting books on biology
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Babies tend to have a similar gut microbiome to their mothers because it is transferred at birth as they pass through the birth canal…close to the anus.
Of course, this is one if the problems with C-sections. It’s interesting when you begin to read up on what researchers are beginning to link our gut microbiota to.
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Gut microbiome is established after birth - during birth (passing through the vagina), immediately after birth (sucking on mom's teat), and at all times post-birth (touching things, people, putting hands in mouth). All of this ends up being swallowed and establishing the gut microbiome.
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Petal_Chatoyance t1_issd8j2 wrote
Put simply, babies are most often born in blood and shit. It's messy. And that shit (or thin liquid, or mucus) contains gut bacteria which the baby needs to survive. All it takes is brief contact. Even a birth in water is not free from this issue, the bacteria get into the water. Gut bacteria are crawling all over the anal/genital region all the time, as well.
Babies born under overly-sterile conditions often suffer digestive problems; that messy birth is actually helpful.
They also get some gut bacteria from the mother's mouth, breasts, and any other part of the body they suck or lick.
Fecal bacteria - gut bacteria - get all over everything in such situations, and some of it gets into the babies mouth. Welcome to biological life; it's disgusting, but it works.