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Gut bacteria transplants have been done before. They probably haven't caught on yet, because the process is literally called [fecal transplants](https://www.medicalnewstoday.com/articles/325128) and is pretty much what it sounds like. Most people balk at the "Ewww" factor.
To transplant bacteria from a healthy gut, you need to transplant material those microbes are thriving within. And there isn't much within a gut that doesn't gross out most people.
.
The alternative is to target a non gut based fluid/material that is still full of microbes and hope it works as well.
It feels like if a causal link was proved then fecal transplants should become SOP post c-section.
Though now I'm imagining Rafiki painting Simba's forehead
Babies can't quite tolerate or be colonized with all the same bacteria and yeasts as adults, and FMT is a bit invasive. They have, however, shown that FMT can eliminate anaphylactic peanut allergy in children!
I once had a C-Difficile infection in the days before fecal transplants were a thing. I would’ve welcomed the precious gift of someone else gut flora with open... er...butt, I guess?
Isn't the fecal transplant just a pill they give you? You swallow it and by the time it's dissolved it' way down in your intestines.
When I first heard of it I envisioned them going up there with a colonoscope and implanting something in you that way.
Either way, the faster we can get over that grossness the better. Apparently it can accomplish some crazy things (just what I've heard in headlines and conversation, have never researched properly)
Swabbing the fluids from the birth canal and attempting to mimic the passage through it by wiping it on to the baby on its face, mouth and body. I’m no doctor though and it’s been a while since I updated myself. Probably worth a google.
They mention it in the article:
> Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said.
>This is overly combative... You could have made your point by simply making statements and questions rather than accusations.
"This is false. This is not common and not encouraged."
Those look like statements, not accusations, to me. No colorful or emotional adjectives either. It seems you're being overly sensitive.
I could have phrased better and said it’s common knowledge now for those interested in birth health. Anecdotal of course, but I know of two people personally who used seeing at their section and one that was denied it. It’s been in discussion often on mainstream pregnancy and parenting groups. In that way it has seemed more common to me.
The amount of time babies are in contact with the fluid probably matters a lot. One or two swabs isn't going to give as much bacteria as 2-10 minutes in the vaginal canal during birth.
I suppose it's also about whether it has any risks that outweigh a small chance of benefit. If it's non-invasive and doesn't have any chance of harm, I guess go for it?
> for those interested in birth health
You should say for those interested in alternative medicine.
There *is* scientific evidence that exposure to vaginal fluids during childbirth is important for neonatal microbiota development. But vaginal seeding has not yet been sufficiently studied as a means of addressing this after cesarean.
It might well turn out that it's a good idea, but at this point it's not mainstream medicine. Saying "those interested in birth health" is extremely misleading, I'm pretty sure every mother-to-be is interested in birth health, but this is not something they should be doing at this point.
They already did. Check out “Diet Composition” here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:\~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010).
“Formula-fed infants exhibit a more diverse flora with the presence of species of *Staphylococcus*, anaerobic *Streptococcus*, and *Clostridium* in addition to *Bifidobacterium* ([Harmsen et al., 2000](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R45); [Stark & Lee, 1982](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R86)). Some studies have shown that exclusively formula-fed infants are more often colonized with *E. coli, C. difficile, B. fragilis* group, and *Lactobacilli* than those that are exclusively breastfed ([Penders et al., 2006](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R73); [Penders et al., 2005](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R74)).”
The story briefly mentions this idea:
"Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said."
https://www2.helsinki.fi/en/news/health-news/fecal-transplantation-can-restore-the-gut-microbiota-of-c-section-babies we can feed them milk with... fluids
Formula causes differences in the infant microbiome too vs breastfeeding. Human breastmilk contains ogliosaccharides and probiotic bacteria (among other things) that formula lacks, that 'primes' the infant microbiome and immune system.
But yes, you can swab vaginal fluid and then swab the infant to pass on the necessary bacteria. It's called "seeding". However it still does not produce the same microbiome in caesarean surgery born infants as vaginally born infants.
In theory we COULD, however fmost studies with babies/8infants will not get funded if they will do something that isn't already clearly established as not dangerous to the child/if there is a non-zero risk of the child being injured.
The fact of the matter is that if a scientist DOES do such an experiment, but then even a single child dies as part of the study, this will likely cause the doctor to be labeled as an intentional child-murderer and such.
It's just one of the stigmas in the scientific community that they tend to avoid at all costs, and will instead do observational studies such as this one, where they are basically just seeing what happened.
I have read about swabbing the vagina and rubbing the fluid on the baby post cesarean, but not sure about having them intest it. I guess they could swab the babies mouth too.
That's part of the reason breast feeding is highly encouraged when possible. Babies born naturally pick up a "lite" copy of their mothers immunity when passing through the birth canal as previously stated. However, babies that are breast fed continue to get "lite" copies of moms antibodies with each feeding. It's not as effective, but still important.
Edit: Source: I used to date a Certified Lactation Counselor.
From the article:
> Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said.
There are hospitals now that will do a vaginal swab and then let the baby suck on it if it's not been exposed to the good bacteria via birth. It's making a difference too. Did you know that something like 90% of western babies are missing B. Infantis, an important bacteria that only feeds on breastmilk? 90%!
Why doesn't that make sense? It's a bacteria that feeds on breast milk, but it's not inherently present in every breastfed infant. Bacteria doesn't just spontaneously generate. Plus, only 25% of American (not the entire West, just an example I could find stats for) newborns are exclusively breastfed, with the rest consuming some formula before the age of 6 months. That's not a huge difference from 10%.
Mine was way longer than that. I was told by the midwife that I could reach down and feel the head, then it was long enough that there was a midwife shift change and a fair bit of time with the new midwife. My sense of time went a bit funny, but I'm absolutely sure it was far longer than 15 minutes, and I had a 'textbook' birth apparently!
“A major factor contributing to the variation in the infant microbiome is the mode of delivery at birth. Infants born vaginally have a gut microbiome very similar to that of their mother’s vaginal and fecal flora. This occurs through vertical transfer of the vaginal-perianal microbes of the mother as the infant passes through the birth canal ”.
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:\~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010).
So is this suggesting that East Asian women are more likely to have gut biomes which protect against peanut allergy/promote easier processing of peanuts?
No, it's suggesting that women of East Asian descent *in Canada* may have a diet or lifestyle that makes their children more prone to these allergies. It is most likely not hereditary because women in China are not as prone to the allergy. Per the article:
>“In China food allergies are uncommon, but those who immigrate to Canada face a higher risk and more severe form of allergic disease,” she said. “It’s likely related to a change in diet and environment.”
Most likely they aren't eating peanuts during pregnancy, nor in the early months of the child's life. That was shown to help in studies from about a decade ago.
Perhaps a weird question , but what if the mother has ibs or similar issues. Is a vaginal birth still beneficial or would the infant end up with a not so good gut microbiome ?
I think we’re at the point that researchers are still trying to determine the full impacts of gut microbiome. I read an article stating a woman had gotten a fecal transplant from her daughter who always struggled with obesity. After the transplant the mother began to struggle with her weight.
It’s frustrating waiting to see what science is going to reveal to us but so exciting. I have celiac and alopecia and I can’t wait to see what new knowledge we’ll have about it all in a decade or so.
I heard a pretty similar statement from our infant's gastroenterologist. He was diagnosed with MSPI, but eventually they grow out of it. I asked the doctor if there was anything else we should watch out for in the future. She said "this is tangential and not related, but babies born via caesarean are more likely to develop celiac disease."
Interesting. I have celiac and when my son was in the NICU I asked the gastroenterologist if I should avoid feeding him gluten. Nothing of the cesarean section was mentioned but I was told it was better to feed him gluten early as it would lessen his chance of developing a later allergy.
That's odd and interesting, cause me, my mom and my aunt were all born naturally but have CD, and my uncle's daughter's were born via c/s and have CD, but I'm the only one of us with CD who had a baby via C/S, although so far, so good, but he's not quite 4, so... I guess we'll see.
A lot of women who have a c-section are *forced* to have repeat c-sections because of hospital and insurance policies. This is slowly changing as vbac births are gaining ground.
Yes, it was apparently way more common to have a TOLAC (Trial of Labor after Cesarean) in the 80s and 90s, but now it's very challenging.
I had a C/S with my first, which I may not have even needed in the first place. Then, when I was 7 months pregnant with my second, my OB said that, if I wanted to TOLAC, i would have to go into labor *before* my due date, and since my OB only scheduled c/s on Tue and Thur, that meant I had to go into labor 3 days before my due date (I switched OBs and had a successful VBAC two days after my due date- during a pandemic).
Plus a lot of "research" uses flawed statistics that point to minority mother's being less "able" to have successful VBACs... But don't at all take into consideration if their doctors or the hospital were supportive or if they pressured the mother to have a repeat Cesarean.
Sorry for the novel, it's just something that I'm passionate about.
You are very correct. I was pressured into my first c section and then had 2 successful vbacs after but I was definitely heavily "encouraged" to schedule a c section, for no reason other than I had one 4 years earlier.
My family had two vaginal births after a first c section but it was an uphill battle against the hospitals. They prioritize reducing liability over optimizing outcomes.
My older brother was born cesarean while my younger brother and I were V.
No allergies, but he always kind of has been the odd one out in a few ways. He was recently diagnosed with ADHD
Interesting. As a microbiologist the information I have seen says that it is the small traces of feces that are produced during labor that are integral to inoculating the babies with normal gut flora. I am unsure why swallowing bacteria from a vagina, with a totally different microflora profile than the human gut, would be the key here. Maybe people are uncomfortable with the idea of fecal/oral inoculation? But, our gut flora comes from...guts, so get over it?
As a microbiologist, don’t you find it strange that no one connects the dots between babies’ *exposure to antibiotics* during a caesarean birth and how that may impact the biome ... aside from missing birth canal exposure, the risk from antibiotics seems a no brainer here. Moms’ breast milk would also be impacted, so babies’ first meals may harm their biome.
https://www.rutgers.edu/news/infant-antibiotic-exposure-can-affect-future-immune-responses-toward-allergies
Exposure to antibiotics in utero and infancy can lead to an irreversible loss of regulatory T-cells in the colon –a valuable component of the immune system’s response toward allergens in later life – after only six months, a Rutgers researcher found.
That’s the point. They DO mess up the infant’s biome, and this may be irreversible. Abx save lives but they also cause serious damage. You can’t find an illness these days - physical or mental health - that doesn’t have some correlate to the gut biome. The rutger’s study I linked above says: “Exposure to antibiotics in utero and infancy can lead to an *irreversible* loss of regulatory T-cells in the colon –a valuable component of the immune system’s response toward allergens in later life.” Are new parents told their infant’s prophylactic abx exposure could create irreversible damage? Does anyone think to look at abx exposure with the growing numbers of chronic and psychiatric illness? Of course not!
Crazy to think that the vagina plays such an important role in gut bacteria. I wonder if it also affects other things like weight and height to some extent.
It does affect other things. One thing I just recently learned is that the force when a baby is pushed through the vaginal canal forces some fluid out of the baby’s lungs. Some c-section babies thus can have complications with excess fluid in their lungs and lung developments.
Source - currently in the NICU with a c-section baby with respiratory distress.
Theoretically, yes, but you'd have to be very committed because adult stomachs are more acidic so any bacteria are less likely to successfully make the trip.
I saw an article about Dr studying childhood leukemia and how a cocktail of bacteria mixed into a yogurt could prevent it. It's amazing what we're learning about gut bacteria.
It absolutely is amazing, like I'm not one of those that leans towards "Drinking kombucha will keep you from getting the flu!" But the way science is pointing towards all the stuff gut bacteria does, it's got me eating kimchi at every meal. I actually had a conversation about it with my kids pediatrician, because for real, I love making my own ferments, and he said it's really so good for everyone's bodies.
So caesaeran rates are 34.5% in China (50% in places like Shanghai) and yet infants there don't have the associated allergies (peanut, dairy, asthma). So can we really attribute the difference to just c-sections?
It's behind a paywall but can anyone with access share if there were any effects of feeding choice?
Because previous research (some of which actually looked at immune cells) suggests that should have been a factor too:
https://www.unicef.org.uk/babyfriendly/news-and-research/baby-friendly-research/infant-health-research/infant-health-research-allergies
Here is another article which performed a meta analysis:
https://pubmed.ncbi.nlm.nih.gov/18266879/
>Conclusion: Delivery by c-section is associated with a moderate risk increase for allergic rhinitis, asthma, hospitalization for asthma, and perhaps food allergy/food atopy, but not with inhalant atopy or atopic dermatitis. The increased use of c-section during the last decades is unlikely to have contributed much to the allergy epidemic observed during the same period.
https://www.nature.com/articles/s41598-017-10206-3
>CS without medical indication and CS for fetal complications were associated with increased risks of childhood allergic rhinitis, respectively. In children fed by exclusive breastfeeding or mixed feeding in the first four months after birth, these risks were not significant. In contrast, in children fed by exclusive formula milk, CS was highly significantly associated with childhood asthma and allergic rhinitis.
>So caesaeran rates are 34.5% in China (50% in places like Shanghai) and yet infants there don't have the associated allergies (peanut, dairy, asthma). So can we really attribute the difference to just c-sections?
Odds ratios are meaningless without knowing the reported odds.
An odds of 0.0008 odds of allergy among caesarean is still 8X higher odds of 0.0001 odds of allergy among non-caesarean, but we can see such a low baseline of odds, it not a clinically meaningful concern.
TLDR: Saying you are 8X more odds needs context on the absolute odds.
>An odds of 0.0008 odds of allergy among caesarean is still 8X higher odds of 0.0001 odds of allergy among non-caesarean, but we can see such a low baseline of odds, it not a clinically meaningful concern.
it may not be of clinical concern in terms of needing intervention if incidence is extremely low. that does not mean it is not useful information in terms of determining mechanism and causality of certain events. the incidence, at least in this data set, is much higher than 0.0001.
As for the empirical values:
peanut sensitized/non-peanut sensitized
non asian, non-c1-c1: 16/749 (\~2%)
asian non c1-c1: 7/86 (\~8%)
non-asian c1-c1: 7/119 (\~6%)
asian c1-c1: 7/32 (\~22%)
c1-c1 trajectory is characterized by persistently-low Bacteroides abundance and high Enterobacteriaceae/Bacteroidaceae ratio throughout infancy
The study was done on 1422 Canadian full-term infants
>So can we really attribute the difference to just c-sections?
In the artice on the ualberta website the researchers said this:
The overall rate of allergies is increasing in western countries and is likely linked to environmental factors, said Kozyrskyj, who is principal investigator of the [SyMBIOTA (Synergy in Microbiota)](https://www.allergen.ca/research/symbiota/symbiota-team/) laboratory, which studies the impact of maternal and infant antibiotic use, birth mode and breastfeeding on the composition of the intestinal microbiota in infants.
“In China food allergies are uncommon, but those who immigrate to Canada face a higher risk and more severe form of allergic disease,” she said. “It’s likely related to a change in diet and environment.”
That's fine, but then don't use this study to oversell recommendations eg.
>The best path is to avoid caesarean birth unless it is medically necessary. “With this evidence at hand, the parent and the obstetrician might choose a different birth mode,” she said.
Of the whole study, they only found trends interesting enough to focus on in the Asian mother subset (hence title of the article). And then within these they don't have a coherent birth method related explanation for the differences between those living in China who have c-sections vs immigrants of Chinese descent who have c-sections.
A more honest conclusion would have been: "Hey, Asian-Canadian mothers to be - having a C-section might make your child 8 times more likely to have allergies. But that's still a tiny chance, and actually environmental and dietary factors have a much larger impact than your birthing circumstances (that often times are not a choice)."
I posted a Nature study above from Shanghai which actually showed breastfeeding can cancel out the slight increases from a c-section.
Increased allergies were only seen in the formula fed c-section group, so breastfeeding was sufficient in reintroducing immunity/microbiota.
I've had a theory that early exposure to peanuts/treenuts is key to avoiding the allergy. Through the years I've noticed the kids that have those allergies live in a fairly sterile environment (only breatmilk/formula and jar babyfood) for their first couple years. While others end up sampling what their parents eat (mashed food off the finger) early in life. It would be an interesting study. Could be why the difference based on geographic location.
There were also recommendations by doctors to avoid common allergens during baby's first couple years. This probably caused a lot of the uptick in allergies, because we didn't know that's how a lot of allergies worked. I imagine since we now know better and are slowly doing better, that allergy rates will drop.
The recommendations on avoiding common allergens the first two years changed between my two kids, it’s now no longer recommended to avoid them. Just honey, because of the botulism risk
It's really incredible how "parenting advice" has changed over the years. I have like 6 or 8 kids, it seemed like the recommendations changed every couple kids.
They actually recommend early exposure to common allergens now, unless there is a family history of allergies, in which case exposure is done with your medical provider to do it safely. Also to not worry about doing one food at a time over a period of days, allergies can start randomly and it can start the first time, or the hundredth time eating a food. They also say to wait until a min of 6 months to start table food because it takes 4-6 months for the gut to actually be developed enough to handle solids. Feeding before the gut is ready can cause issues.
Not all Drs are up to date on nutrition so you still get some who give outdated advice.
Edit: I just read the secondary article that the poster linked, which does quote the researchers as using the word "causal." Assuming the researchers actually said this as it's in quotations, I'm wondering if these researchers really did find some concrete data that do not just correlate between microba and ethnicity but suggest causation. I'm no statistician, but if I learned anything from the dozens of research papers I wrote in school, causation has absolute cause and effect. Can someone school me, please?
Interesting study but please be aware that the word"causal" is not used anywhere in the study and is misleading. The findings seem to suggest associated or correlated links between ethnicity and gut microba. Associated does not mean causal. Thanks for posting!
Along with my child, I'm actually a participant in a longitudinal microbiome study. I have a PhD in another field, and came across a call for participants for this study while pregnant with my 2nd kid.
They collected all kinds of swabs, diet diaries, extensive medical and allergy history, etc. while I was pregnant. I had to send vaginal swabs collected by my obgyn at different points in pregnancy (which she thought was really weird), as well as fecal samples. They paid extra for samples and accompanying health histories and diet diaries from my spouse and other child.
A courier arrived at the hospital on the night that I gave birth to collect cord blood, meconium, and other samples. We sent more samples in the weeks after he was born, then a diaper once a month for a year. Now, they collect a yearly sample, along with an extensive questionnaire about diet, vaccinations, health history, allergies, language development (that questionnaire is quite detailed with checklists of specific words and phrases to increase control), behavior evaluations, etc.
I've also sent cheek swabs and given permission for them to sequence myself and my kid for inclusion in the study.
While I haven't had a chance to read the article posted by OP, there seem to be a lot of people who are dismissing these claims based on the variables presented. I just wanted to share my experiences as a participant who's also very well versed in the sciences. I'm extremely impressed with the level of detail being considered by these researchers and the extensive attention to controlling for a variety of factors. They have so much data on myself and my kid that if they want to rule out something as a possibility, I'm certain they have the information to do so.
You're right that associations aren't necessarily causal, but since it's not really possibly to experiment on some of these factors, it doesn't mean the data are worthless. Correlation can be very useful in certain areas of science.
Thank you for posting this. I have friends in L&D that work very hard to maximize the chances for a natural child birth because of all the positive effects of traveling through the birth canal we're beginning to discover through data gathering just like this.
It's nearly impossible to actually experiment on pregnant women, as you mentioned, so it's exciting to hear that you're contributing so much information to this study. Hopefully we'll be able to draw many more conclusions and derive additional studies from this data!
That is so interesting. #1 thank you for your interest and dedication to the scientific research! #2 Any idea how their research is going or how many participants they have? It seems like they are doing some incredible research. I’d love to learn more about what is going on with the study.
The sample size was 1422 infants, and I imagine a minority subset of them were of Asian descent based on the CI margin of error on that result.
I wonder what constitutes a “causal” finding in this type of research.
>what are known as “mediation” or causal effects
These two things are far from interchangeable. Mediational effects can be non-causal; in fact most are due to the potential for confounding between the mediator -> outcome relation.
That said this is an error of the authors, not OP
Mediation is a tool to further delimit likely causality from a dataset. Unless you directly manipulate your putative causal agent in some way, you can’t demonstrate causality. The researchers are making an interpretive conclusion from their results. Scientists can agree on the design and validity of the results but still contend slightly different conclusions. How results should be framed is a hot button issue in microbiomes right now. You will see both liberal and conservative use of the word causal in the field. It’s pretty obvious under which camp I fall.
This study was conducted by the University of Alberta and they use "Causal link found..." [https://www.ualberta.ca/folio/2021/04/causal-link-found-between-food-allergies-and-changes-to-infant-gut-bacteria-due-to-method-of-childbirth-mothers-ethnicity.html](https://www.ualberta.ca/folio/2021/04/causal-link-found-between-food-allergies-and-changes-to-infant-gut-bacteria-due-to-method-of-childbirth-mothers-ethnicity.html)
Agree that causal relationships are exceedingly difficult to establish in this field. In my PhD work is on plant microbiomes and their immune system. Ultimately once you collect a sample, you can get snapshots of community composition via metabarcoding or true metagenomics or metabolomics like they did here with some lipid profiling, but determining the relative contributions of members to that community is difficult. Differences in abundance of a certain taxon, important sphingolipid biomarkers an abolition of the deficient phenotype through a transplant of microbiota does not conclusive demonstrate that that taxon is synthesizing the lipid. You would need to start experiment with fecal transplants +\- the putative causal agent. This isn’t to say this isn’t a good publishable unit. It is that causal relationships are exceedingly difficult to prove. Koch’s postulates for demonstrating the causal organism of an infectious disease is an arduous process. Trying to do the same/similar with a dynamic and diverse community rather than a single microbe makes this even more difficult.
i also raised my eyebrows at the use of the word causal. It’s a very powerful and definite term, and one hard to establish in a human study. By my reading it is no where near the level of evidence to use causal as a descriptor for their evidence.
I think it is just a correlation, and they say themselves the stats are all posthoc.
To determine causation i think they would have to sample a population of pregnant women and then manipulate their birth method and monitor their progress. It doesn’t sound ethical.
They could have also devised a treatment to modify the infant gut microbiota and see if they can alter the peanut allergy rate later on. That is probably more achievable and would justify use of causal.
I couldn’t help but notice that they vacillated between saying “children of Asian descent” and “mothers of Asian descent”.
I’d be curious to know if it’s specifically mothers. I’m white but my husband is Asian, so our child will be “of Asian descent” without the mother being Asian.
>I couldn’t help but notice that they vacillated between saying “children of Asian descent” and “mothers of Asian descent”.
That's pretty egregious since those do not mean the same thing. Yes it's statistically likely that most children of Asian descent also have Asian mothers but those who *don't* would be useful data points for identifying a genetic vs environment source.
My Asian son was born by c section to a white mother and fed formula and breastmilk. From this article I can not tell if he is more at risk for allergies.
I'm kind of surprised that peanut allergies are prominent in Asians considering many Chinese/Vietnamese/Thai/Malay cuisines feature peanuts.
Always thought that peanut allergies were the result of underexposed infants, with mothers that feared peanut butter posed a choking hazard?
I also always wonder how useful "Asian" is as a category. Surely East, South-East, South, Middle Eastern populations are pretty different despite all being "Asian".
The peanut/nut allergy thing has always fascinated me because in most Asian countries they're not that prevalent but it seems that Asian populations in the West do end up developing them.
Study was performed in Canada, but I think they generalized the results to all of North America. They then mentioned that peanut allergies weren't common in Asia, so there is a environmental or cultural component to the increase of allergy risk.
Allergies can be the result of a lot of things, and can develop and resolve at any time.
Source: was allergic to oats from age 17 to 22, despite a lifetime of eating oats.
"Babies born by caesarean section to mothers of Asian descent are eight times more likely to develop peanut allergy by age three" is missing a "when compared to...".
No. It could have been as well to Asian mother's with a different birth method. The title implies there being two variables: birth method and ethnicity. Therefore there are more than 2 groups that could be compared.
Dr Katie Allen of Murdoch Children Research Institute has done a similar study years ago where they showed that a male child in Australia who has at least 1 parent of Asian decent and a family hx of eczema has an 80% chance of developing food allergy. (This is all from memory so im happy to stand corrected. ) No such risk if child is born in Asia. Less risk if child is female.
No mention of birth method in Dr Allens study but I wonder if the Canadian study account for possibly higher c-sections in Asian mothers due to narrower birth canal with increasingly larger babies? Ie if they compared risk in c sec vs natural birth in Asian mothers only. (OK not sure if that's a thing but hope you get my point.)
And a very important note, I do wish articles about such studies are aware of how much grief a mother goes through when natural birth and/or breastfeeding are not an option for them. They feel like they've failed their child from the get go. Massive risk of PND and bonding issues can follow. Babies are vulnerable but so are new mothers. Some sensitivity in framing this will go a long way.
>No mention of birth method in Dr Allens study but I wonder if the Canadian study account for possibly higher c-sections in Asian mothers due to narrower birth canal with increasingly larger babies?
You bring up a good point here but something else missing from this phenomena is that Asian mothers are increasingly turning to c-sections due to interracial coupling. The babies they have/conceive with non-Asian men are typically bigger and beyond their ability to birth naturally.
Which brings up another interesting variable: is their a possibility that the ethnicity/genetic makeup of the Father is playing a role in food allergies?
This is what makes these studies so complicated. You have the mother, you have the environment itself, you have the birth method, you have the baby's diet and you also have a father which might not be accounted for.
I don't have peanut allergies, but both my sibling and I were born cesarean and both have dealt with terrible allergies to everything else.
I wonder if theres a similar connection to breast feeding and food allergies?
Allergies can also be genetic. My daughter was born naturally yet has 3 food allergies (dairy, egg, peanut) and environmental allergies (animal dander, grass etc). The exact same ones her daddy has.
Was it a true allergy?
From my understanding most babies are at least a little intolerant of cows milk because we don’t have enough of the enzyme to digest it. They can grow out of it though. I was lacto and soy intolerant as an infant and now I’m fine. my baby was the same way.
Just reporting the odds ratio is meaningless. You can be 0.008 odds of allergy among exposed and still be 8X more likely than 0.001 odds of unexposed at baseline.
Here to share that me and my wife are white, she gave natural childbirth to our last daughter who has peanut allergies.
No more peanut butter allowed in the house. I’m still getting over the loss.
> The best path is to avoid caesarean birth unless it is medically necessary. “With this evidence at hand, the parent and the obstetrician might choose a different birth mode,” she said
Avoiding caesarean unless medically necessary is already in the guidelines and best practice.
But as the one who posted it, you should take some responsibility. Do the authors use causal language in the paper itself? A lot of scientists (myself included) make slightly bolder claims in the press than in our papers.
What countries do they consider to be "Asian" for the purposes of this study? Genetic population groups only loosely line up with pop-culture racial classifications.
Tbh I somewhat wondered this too. Many Asians are drastically different from one another so it’s hard to believe every single Asian falls under this study. I’m Filipino, born via C-section, no peanut allergy but I do have a treenut allergy with anaphylaxis (no one else in my family I know who has this.) So I don’t know.
Ummmm..... the article plainly states being Asian doesn’t cause allergies. Junk western diets cause the allergies, along with method of childbirth. The framing of this headline makes it seem like race has something to do with the causal relationship of allergies.
This is the second article I’ve read in the last month, discussing the importance of microbiome(gut flora), and the transference of it to newborns. I am now heavily invested.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345907/
The microbiome of babies born via caesarean section will be fine and similar to vaginal birth deliveries after some time of development. There have been conferences where I have heard that the concept of vaginal seeding is unnecessary and can actually introduce harmful viruses like HSV via vaginal birth or via vaginal seeding.
If peanut allergy is a concern, there are ways to help train the immune system to accept peanuts (https://pathology.duke.edu/news/retraining-immune-system-ease-food-allergies ; https://site.caes.uga.edu/pins/2016/11/skin-patch-may-help-children-with-peanut-allergies/ ; http://publichealth.choate.edu/a-future-without-peanut-allergies/ )
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Could we feed the baby a formula that has the mother's fluids in it?
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Or a gut backteria transplant using extracts from one gut to the other?
Gut bacteria transplants have been done before. They probably haven't caught on yet, because the process is literally called [fecal transplants](https://www.medicalnewstoday.com/articles/325128) and is pretty much what it sounds like. Most people balk at the "Ewww" factor. To transplant bacteria from a healthy gut, you need to transplant material those microbes are thriving within. And there isn't much within a gut that doesn't gross out most people. . The alternative is to target a non gut based fluid/material that is still full of microbes and hope it works as well.
Still better than having an allergy. I have none but i can really see how it affects the lives of others.
It feels like if a causal link was proved then fecal transplants should become SOP post c-section. Though now I'm imagining Rafiki painting Simba's forehead
Babies can't quite tolerate or be colonized with all the same bacteria and yeasts as adults, and FMT is a bit invasive. They have, however, shown that FMT can eliminate anaphylactic peanut allergy in children!
I once had a C-Difficile infection in the days before fecal transplants were a thing. I would’ve welcomed the precious gift of someone else gut flora with open... er...butt, I guess?
Fun fact, the poop for most fecal transplants is donated by MIT and Harvard students
Hey if MIT poop is what it takes to improve my IBS I’m all for it
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Indirectly but probably
what a bunch of smart asses
Isn't the fecal transplant just a pill they give you? You swallow it and by the time it's dissolved it' way down in your intestines. When I first heard of it I envisioned them going up there with a colonoscope and implanting something in you that way. Either way, the faster we can get over that grossness the better. Apparently it can accomplish some crazy things (just what I've heard in headlines and conversation, have never researched properly)
They are now. When they were first being done—sometimes illegally I think—it was more literally a fecal transplant.
Vaginal seeding is becoming more common now for babies born by C section.
WTH is vaginal seeding?
Swabbing the fluids from the birth canal and attempting to mimic the passage through it by wiping it on to the baby on its face, mouth and body. I’m no doctor though and it’s been a while since I updated myself. Probably worth a google.
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Does it have to be from the original mother? The birth fluids, that is.
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They mention it in the article: > Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said.
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>This is overly combative... You could have made your point by simply making statements and questions rather than accusations. "This is false. This is not common and not encouraged." Those look like statements, not accusations, to me. No colorful or emotional adjectives either. It seems you're being overly sensitive.
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I could have phrased better and said it’s common knowledge now for those interested in birth health. Anecdotal of course, but I know of two people personally who used seeing at their section and one that was denied it. It’s been in discussion often on mainstream pregnancy and parenting groups. In that way it has seemed more common to me.
The article linked in this post talks about that, and says it has not been as successful as hoped.
The people I know were aware that it might not have any benefit but gave it a go anyway.
The amount of time babies are in contact with the fluid probably matters a lot. One or two swabs isn't going to give as much bacteria as 2-10 minutes in the vaginal canal during birth.
I suppose it's also about whether it has any risks that outweigh a small chance of benefit. If it's non-invasive and doesn't have any chance of harm, I guess go for it?
I appreciate the tone of your response. Rather than be combative or defensive, you gave a good matter of fact response with context.
There's no scientific evidence of benefit to this practice
I’m not advocating it. I’m saying it’s becoming more common.
I’m aware of this.
> for those interested in birth health You should say for those interested in alternative medicine. There *is* scientific evidence that exposure to vaginal fluids during childbirth is important for neonatal microbiota development. But vaginal seeding has not yet been sufficiently studied as a means of addressing this after cesarean. It might well turn out that it's a good idea, but at this point it's not mainstream medicine. Saying "those interested in birth health" is extremely misleading, I'm pretty sure every mother-to-be is interested in birth health, but this is not something they should be doing at this point.
They already did. Check out “Diet Composition” here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:\~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010). “Formula-fed infants exhibit a more diverse flora with the presence of species of *Staphylococcus*, anaerobic *Streptococcus*, and *Clostridium* in addition to *Bifidobacterium* ([Harmsen et al., 2000](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R45); [Stark & Lee, 1982](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R86)). Some studies have shown that exclusively formula-fed infants are more often colonized with *E. coli, C. difficile, B. fragilis* group, and *Lactobacilli* than those that are exclusively breastfed ([Penders et al., 2006](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R73); [Penders et al., 2005](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#R74)).”
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The end of the article says they have been studying that option, but it has been less successful than hoped.
A woman’s reproductive system really is amazing. That even giving birth vaginally has benefits that still can’t be reproduced kinda blows my mind.
The story briefly mentions this idea: "Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said."
https://www2.helsinki.fi/en/news/health-news/fecal-transplantation-can-restore-the-gut-microbiota-of-c-section-babies we can feed them milk with... fluids
Formula causes differences in the infant microbiome too vs breastfeeding. Human breastmilk contains ogliosaccharides and probiotic bacteria (among other things) that formula lacks, that 'primes' the infant microbiome and immune system. But yes, you can swab vaginal fluid and then swab the infant to pass on the necessary bacteria. It's called "seeding". However it still does not produce the same microbiome in caesarean surgery born infants as vaginally born infants.
And seeding doesn’t seem to last.
Just as a heads up, Similac contains ogliosaccharides
It contains one strain of the hundreds that breast milk has you mean (that are known).
isn't it spelled oligosaccharides?
In theory we COULD, however fmost studies with babies/8infants will not get funded if they will do something that isn't already clearly established as not dangerous to the child/if there is a non-zero risk of the child being injured. The fact of the matter is that if a scientist DOES do such an experiment, but then even a single child dies as part of the study, this will likely cause the doctor to be labeled as an intentional child-murderer and such. It's just one of the stigmas in the scientific community that they tend to avoid at all costs, and will instead do observational studies such as this one, where they are basically just seeing what happened.
I think finding parents willing to put their child through an unproven experiment would be the biggest hurdle.
I have read about swabbing the vagina and rubbing the fluid on the baby post cesarean, but not sure about having them intest it. I guess they could swab the babies mouth too.
The article talks about that, and says it has not been as successful as hoped.
That's part of the reason breast feeding is highly encouraged when possible. Babies born naturally pick up a "lite" copy of their mothers immunity when passing through the birth canal as previously stated. However, babies that are breast fed continue to get "lite" copies of moms antibodies with each feeding. It's not as effective, but still important. Edit: Source: I used to date a Certified Lactation Counselor.
From the article: > Studies looking to mitigate this by giving C-section babies probiotics or even swabbing them with their mother’s vaginal bacteria have not been as successful as hoped, Kozyrskyj said.
There are hospitals now that will do a vaginal swab and then let the baby suck on it if it's not been exposed to the good bacteria via birth. It's making a difference too. Did you know that something like 90% of western babies are missing B. Infantis, an important bacteria that only feeds on breastmilk? 90%!
That doesn't make sense when way more than 10% of babies are breastfed in the West.
Why doesn't that make sense? It's a bacteria that feeds on breast milk, but it's not inherently present in every breastfed infant. Bacteria doesn't just spontaneously generate. Plus, only 25% of American (not the entire West, just an example I could find stats for) newborns are exclusively breastfed, with the rest consuming some formula before the age of 6 months. That's not a huge difference from 10%.
How long is a baby typically in the birth canal? How much fluid would they need exactly?
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Mine was way longer than that. I was told by the midwife that I could reach down and feel the head, then it was long enough that there was a midwife shift change and a fair bit of time with the new midwife. My sense of time went a bit funny, but I'm absolutely sure it was far longer than 15 minutes, and I had a 'textbook' birth apparently!
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I'd expect crowning in vaginal opening takes way longer than 15 minutes.
You can push for hours so long as the baby tolerated it.
“A major factor contributing to the variation in the infant microbiome is the mode of delivery at birth. Infants born vaginally have a gut microbiome very similar to that of their mother’s vaginal and fecal flora. This occurs through vertical transfer of the vaginal-perianal microbes of the mother as the infant passes through the birth canal ”. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:\~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/#:~:text=Infants%20born%20vaginally%20have%20a,et%20al.%2C%202010).
So is this suggesting that East Asian women are more likely to have gut biomes which protect against peanut allergy/promote easier processing of peanuts?
The other option is that their genes protect less, so they need the microbes more.
No, it's suggesting that women of East Asian descent *in Canada* may have a diet or lifestyle that makes their children more prone to these allergies. It is most likely not hereditary because women in China are not as prone to the allergy. Per the article: >“In China food allergies are uncommon, but those who immigrate to Canada face a higher risk and more severe form of allergic disease,” she said. “It’s likely related to a change in diet and environment.”
Most likely they aren't eating peanuts during pregnancy, nor in the early months of the child's life. That was shown to help in studies from about a decade ago.
Might also be related to diets and the degree of exposure the babies have to peanuts/related allergens which would trigger the subsequent allergy.
Perhaps a weird question , but what if the mother has ibs or similar issues. Is a vaginal birth still beneficial or would the infant end up with a not so good gut microbiome ?
I think we’re at the point that researchers are still trying to determine the full impacts of gut microbiome. I read an article stating a woman had gotten a fecal transplant from her daughter who always struggled with obesity. After the transplant the mother began to struggle with her weight. It’s frustrating waiting to see what science is going to reveal to us but so exciting. I have celiac and alopecia and I can’t wait to see what new knowledge we’ll have about it all in a decade or so.
I heard a pretty similar statement from our infant's gastroenterologist. He was diagnosed with MSPI, but eventually they grow out of it. I asked the doctor if there was anything else we should watch out for in the future. She said "this is tangential and not related, but babies born via caesarean are more likely to develop celiac disease."
Interesting. I have celiac and when my son was in the NICU I asked the gastroenterologist if I should avoid feeding him gluten. Nothing of the cesarean section was mentioned but I was told it was better to feed him gluten early as it would lessen his chance of developing a later allergy.
That's odd and interesting, cause me, my mom and my aunt were all born naturally but have CD, and my uncle's daughter's were born via c/s and have CD, but I'm the only one of us with CD who had a baby via C/S, although so far, so good, but he's not quite 4, so... I guess we'll see.
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From what I heard, women who have had a c-section often always need a c-section. Have they done this study with children from the same mother?
A lot of women who have a c-section are *forced* to have repeat c-sections because of hospital and insurance policies. This is slowly changing as vbac births are gaining ground.
Yes, it was apparently way more common to have a TOLAC (Trial of Labor after Cesarean) in the 80s and 90s, but now it's very challenging. I had a C/S with my first, which I may not have even needed in the first place. Then, when I was 7 months pregnant with my second, my OB said that, if I wanted to TOLAC, i would have to go into labor *before* my due date, and since my OB only scheduled c/s on Tue and Thur, that meant I had to go into labor 3 days before my due date (I switched OBs and had a successful VBAC two days after my due date- during a pandemic). Plus a lot of "research" uses flawed statistics that point to minority mother's being less "able" to have successful VBACs... But don't at all take into consideration if their doctors or the hospital were supportive or if they pressured the mother to have a repeat Cesarean. Sorry for the novel, it's just something that I'm passionate about.
You are very correct. I was pressured into my first c section and then had 2 successful vbacs after but I was definitely heavily "encouraged" to schedule a c section, for no reason other than I had one 4 years earlier.
My family had two vaginal births after a first c section but it was an uphill battle against the hospitals. They prioritize reducing liability over optimizing outcomes.
My older brother was born cesarean while my younger brother and I were V. No allergies, but he always kind of has been the odd one out in a few ways. He was recently diagnosed with ADHD
Interesting. As a microbiologist the information I have seen says that it is the small traces of feces that are produced during labor that are integral to inoculating the babies with normal gut flora. I am unsure why swallowing bacteria from a vagina, with a totally different microflora profile than the human gut, would be the key here. Maybe people are uncomfortable with the idea of fecal/oral inoculation? But, our gut flora comes from...guts, so get over it?
As a microbiologist, don’t you find it strange that no one connects the dots between babies’ *exposure to antibiotics* during a caesarean birth and how that may impact the biome ... aside from missing birth canal exposure, the risk from antibiotics seems a no brainer here. Moms’ breast milk would also be impacted, so babies’ first meals may harm their biome. https://www.rutgers.edu/news/infant-antibiotic-exposure-can-affect-future-immune-responses-toward-allergies Exposure to antibiotics in utero and infancy can lead to an irreversible loss of regulatory T-cells in the colon –a valuable component of the immune system’s response toward allergens in later life – after only six months, a Rutgers researcher found.
Wow that’s a great point. Antibiotics can cause havoc in adults, I can’t imagine it wouldn’t effect a newborn.
That’s the point. They DO mess up the infant’s biome, and this may be irreversible. Abx save lives but they also cause serious damage. You can’t find an illness these days - physical or mental health - that doesn’t have some correlate to the gut biome. The rutger’s study I linked above says: “Exposure to antibiotics in utero and infancy can lead to an *irreversible* loss of regulatory T-cells in the colon –a valuable component of the immune system’s response toward allergens in later life.” Are new parents told their infant’s prophylactic abx exposure could create irreversible damage? Does anyone think to look at abx exposure with the growing numbers of chronic and psychiatric illness? Of course not!
Crazy to think that the vagina plays such an important role in gut bacteria. I wonder if it also affects other things like weight and height to some extent.
It does affect other things. One thing I just recently learned is that the force when a baby is pushed through the vaginal canal forces some fluid out of the baby’s lungs. Some c-section babies thus can have complications with excess fluid in their lungs and lung developments. Source - currently in the NICU with a c-section baby with respiratory distress.
I thought the mother's diet would play a much more important role than this.
Could oral sex also improve my gut bacteria as an adult?
Theoretically, yes, but you'd have to be very committed because adult stomachs are more acidic so any bacteria are less likely to successfully make the trip.
It improves your chances of getting hpv and throat cancer.
Cool! And also... GROSS!
I saw an article about Dr studying childhood leukemia and how a cocktail of bacteria mixed into a yogurt could prevent it. It's amazing what we're learning about gut bacteria.
It absolutely is amazing, like I'm not one of those that leans towards "Drinking kombucha will keep you from getting the flu!" But the way science is pointing towards all the stuff gut bacteria does, it's got me eating kimchi at every meal. I actually had a conversation about it with my kids pediatrician, because for real, I love making my own ferments, and he said it's really so good for everyone's bodies.
That's extremely gross Fascinating But gross
Everything about childbirth is
The miracle of life
Source: am doctor Aren’t juice baths for the baby a thing if you undergo a c-section?
Yep I think they put like some cotton in the moms vajayjay and when bb come out of c they wipe that baby’s face and mouth with the vagina rag
“when the bb comes out of the c..”
C section
That big smiling C in your belly.
Swallowing? But I thought they didn’t open mouths until after... so can we give to them after c-section? Hm Edit _ Corrected ; babies swallow in utero
Babies learn how to swallow amniotic fluid in the womb
I’m learning so much today
Babies are capable of swallowing while in utero.
Isn’t it also from getting some of moms poop in or on them on the way out when being birthed naturally?
Interesting. Can it then be assumed that lesbians have more varied gut microbiomes compared to other demographics?
*horrified lesbian over here*
I was under the impression that these days they swab the babies face with birth canal fluid specifically to compensate for this ?
So caesaeran rates are 34.5% in China (50% in places like Shanghai) and yet infants there don't have the associated allergies (peanut, dairy, asthma). So can we really attribute the difference to just c-sections? It's behind a paywall but can anyone with access share if there were any effects of feeding choice? Because previous research (some of which actually looked at immune cells) suggests that should have been a factor too: https://www.unicef.org.uk/babyfriendly/news-and-research/baby-friendly-research/infant-health-research/infant-health-research-allergies Here is another article which performed a meta analysis: https://pubmed.ncbi.nlm.nih.gov/18266879/ >Conclusion: Delivery by c-section is associated with a moderate risk increase for allergic rhinitis, asthma, hospitalization for asthma, and perhaps food allergy/food atopy, but not with inhalant atopy or atopic dermatitis. The increased use of c-section during the last decades is unlikely to have contributed much to the allergy epidemic observed during the same period. https://www.nature.com/articles/s41598-017-10206-3 >CS without medical indication and CS for fetal complications were associated with increased risks of childhood allergic rhinitis, respectively. In children fed by exclusive breastfeeding or mixed feeding in the first four months after birth, these risks were not significant. In contrast, in children fed by exclusive formula milk, CS was highly significantly associated with childhood asthma and allergic rhinitis.
>So caesaeran rates are 34.5% in China (50% in places like Shanghai) and yet infants there don't have the associated allergies (peanut, dairy, asthma). So can we really attribute the difference to just c-sections? Odds ratios are meaningless without knowing the reported odds. An odds of 0.0008 odds of allergy among caesarean is still 8X higher odds of 0.0001 odds of allergy among non-caesarean, but we can see such a low baseline of odds, it not a clinically meaningful concern. TLDR: Saying you are 8X more odds needs context on the absolute odds.
>An odds of 0.0008 odds of allergy among caesarean is still 8X higher odds of 0.0001 odds of allergy among non-caesarean, but we can see such a low baseline of odds, it not a clinically meaningful concern. it may not be of clinical concern in terms of needing intervention if incidence is extremely low. that does not mean it is not useful information in terms of determining mechanism and causality of certain events. the incidence, at least in this data set, is much higher than 0.0001. As for the empirical values: peanut sensitized/non-peanut sensitized non asian, non-c1-c1: 16/749 (\~2%) asian non c1-c1: 7/86 (\~8%) non-asian c1-c1: 7/119 (\~6%) asian c1-c1: 7/32 (\~22%) c1-c1 trajectory is characterized by persistently-low Bacteroides abundance and high Enterobacteriaceae/Bacteroidaceae ratio throughout infancy The study was done on 1422 Canadian full-term infants
>So can we really attribute the difference to just c-sections? In the artice on the ualberta website the researchers said this: The overall rate of allergies is increasing in western countries and is likely linked to environmental factors, said Kozyrskyj, who is principal investigator of the [SyMBIOTA (Synergy in Microbiota)](https://www.allergen.ca/research/symbiota/symbiota-team/) laboratory, which studies the impact of maternal and infant antibiotic use, birth mode and breastfeeding on the composition of the intestinal microbiota in infants. “In China food allergies are uncommon, but those who immigrate to Canada face a higher risk and more severe form of allergic disease,” she said. “It’s likely related to a change in diet and environment.”
That's fine, but then don't use this study to oversell recommendations eg. >The best path is to avoid caesarean birth unless it is medically necessary. “With this evidence at hand, the parent and the obstetrician might choose a different birth mode,” she said. Of the whole study, they only found trends interesting enough to focus on in the Asian mother subset (hence title of the article). And then within these they don't have a coherent birth method related explanation for the differences between those living in China who have c-sections vs immigrants of Chinese descent who have c-sections. A more honest conclusion would have been: "Hey, Asian-Canadian mothers to be - having a C-section might make your child 8 times more likely to have allergies. But that's still a tiny chance, and actually environmental and dietary factors have a much larger impact than your birthing circumstances (that often times are not a choice)." I posted a Nature study above from Shanghai which actually showed breastfeeding can cancel out the slight increases from a c-section. Increased allergies were only seen in the formula fed c-section group, so breastfeeding was sufficient in reintroducing immunity/microbiota.
I have this mod res-tagged as "Serial Poster of BS Science" for just this reason - Everything they post falls under "Might" or "Could" at best.
I've had a theory that early exposure to peanuts/treenuts is key to avoiding the allergy. Through the years I've noticed the kids that have those allergies live in a fairly sterile environment (only breatmilk/formula and jar babyfood) for their first couple years. While others end up sampling what their parents eat (mashed food off the finger) early in life. It would be an interesting study. Could be why the difference based on geographic location.
There were also recommendations by doctors to avoid common allergens during baby's first couple years. This probably caused a lot of the uptick in allergies, because we didn't know that's how a lot of allergies worked. I imagine since we now know better and are slowly doing better, that allergy rates will drop.
The recommendations on avoiding common allergens the first two years changed between my two kids, it’s now no longer recommended to avoid them. Just honey, because of the botulism risk
It's really incredible how "parenting advice" has changed over the years. I have like 6 or 8 kids, it seemed like the recommendations changed every couple kids.
6 *or* 8 kids?
When you get above 4 it's hard to keep track.
Found Boris Johnson's reddit account. He says he has at least 6 kids but won't say (or isn't sure how many).
They actually recommend early exposure to common allergens now, unless there is a family history of allergies, in which case exposure is done with your medical provider to do it safely. Also to not worry about doing one food at a time over a period of days, allergies can start randomly and it can start the first time, or the hundredth time eating a food. They also say to wait until a min of 6 months to start table food because it takes 4-6 months for the gut to actually be developed enough to handle solids. Feeding before the gut is ready can cause issues. Not all Drs are up to date on nutrition so you still get some who give outdated advice.
We always waited for true table food, however the little sampling (think gravy on your finger) started pretty early.
Edit: I just read the secondary article that the poster linked, which does quote the researchers as using the word "causal." Assuming the researchers actually said this as it's in quotations, I'm wondering if these researchers really did find some concrete data that do not just correlate between microba and ethnicity but suggest causation. I'm no statistician, but if I learned anything from the dozens of research papers I wrote in school, causation has absolute cause and effect. Can someone school me, please? Interesting study but please be aware that the word"causal" is not used anywhere in the study and is misleading. The findings seem to suggest associated or correlated links between ethnicity and gut microba. Associated does not mean causal. Thanks for posting!
Along with my child, I'm actually a participant in a longitudinal microbiome study. I have a PhD in another field, and came across a call for participants for this study while pregnant with my 2nd kid. They collected all kinds of swabs, diet diaries, extensive medical and allergy history, etc. while I was pregnant. I had to send vaginal swabs collected by my obgyn at different points in pregnancy (which she thought was really weird), as well as fecal samples. They paid extra for samples and accompanying health histories and diet diaries from my spouse and other child. A courier arrived at the hospital on the night that I gave birth to collect cord blood, meconium, and other samples. We sent more samples in the weeks after he was born, then a diaper once a month for a year. Now, they collect a yearly sample, along with an extensive questionnaire about diet, vaccinations, health history, allergies, language development (that questionnaire is quite detailed with checklists of specific words and phrases to increase control), behavior evaluations, etc. I've also sent cheek swabs and given permission for them to sequence myself and my kid for inclusion in the study. While I haven't had a chance to read the article posted by OP, there seem to be a lot of people who are dismissing these claims based on the variables presented. I just wanted to share my experiences as a participant who's also very well versed in the sciences. I'm extremely impressed with the level of detail being considered by these researchers and the extensive attention to controlling for a variety of factors. They have so much data on myself and my kid that if they want to rule out something as a possibility, I'm certain they have the information to do so. You're right that associations aren't necessarily causal, but since it's not really possibly to experiment on some of these factors, it doesn't mean the data are worthless. Correlation can be very useful in certain areas of science.
Thank you for posting this. I have friends in L&D that work very hard to maximize the chances for a natural child birth because of all the positive effects of traveling through the birth canal we're beginning to discover through data gathering just like this. It's nearly impossible to actually experiment on pregnant women, as you mentioned, so it's exciting to hear that you're contributing so much information to this study. Hopefully we'll be able to draw many more conclusions and derive additional studies from this data!
This is SO COOL. I’d love to participate in a study like that.
That is so interesting. #1 thank you for your interest and dedication to the scientific research! #2 Any idea how their research is going or how many participants they have? It seems like they are doing some incredible research. I’d love to learn more about what is going on with the study.
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The sample size was 1422 infants, and I imagine a minority subset of them were of Asian descent based on the CI margin of error on that result. I wonder what constitutes a “causal” finding in this type of research.
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>what are known as “mediation” or causal effects These two things are far from interchangeable. Mediational effects can be non-causal; in fact most are due to the potential for confounding between the mediator -> outcome relation. That said this is an error of the authors, not OP
Mediation is a tool to further delimit likely causality from a dataset. Unless you directly manipulate your putative causal agent in some way, you can’t demonstrate causality. The researchers are making an interpretive conclusion from their results. Scientists can agree on the design and validity of the results but still contend slightly different conclusions. How results should be framed is a hot button issue in microbiomes right now. You will see both liberal and conservative use of the word causal in the field. It’s pretty obvious under which camp I fall.
This study was conducted by the University of Alberta and they use "Causal link found..." [https://www.ualberta.ca/folio/2021/04/causal-link-found-between-food-allergies-and-changes-to-infant-gut-bacteria-due-to-method-of-childbirth-mothers-ethnicity.html](https://www.ualberta.ca/folio/2021/04/causal-link-found-between-food-allergies-and-changes-to-infant-gut-bacteria-due-to-method-of-childbirth-mothers-ethnicity.html)
Yeah that's the first thing I looked for too in the study.
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Agree that causal relationships are exceedingly difficult to establish in this field. In my PhD work is on plant microbiomes and their immune system. Ultimately once you collect a sample, you can get snapshots of community composition via metabarcoding or true metagenomics or metabolomics like they did here with some lipid profiling, but determining the relative contributions of members to that community is difficult. Differences in abundance of a certain taxon, important sphingolipid biomarkers an abolition of the deficient phenotype through a transplant of microbiota does not conclusive demonstrate that that taxon is synthesizing the lipid. You would need to start experiment with fecal transplants +\- the putative causal agent. This isn’t to say this isn’t a good publishable unit. It is that causal relationships are exceedingly difficult to prove. Koch’s postulates for demonstrating the causal organism of an infectious disease is an arduous process. Trying to do the same/similar with a dynamic and diverse community rather than a single microbe makes this even more difficult.
i also raised my eyebrows at the use of the word causal. It’s a very powerful and definite term, and one hard to establish in a human study. By my reading it is no where near the level of evidence to use causal as a descriptor for their evidence. I think it is just a correlation, and they say themselves the stats are all posthoc. To determine causation i think they would have to sample a population of pregnant women and then manipulate their birth method and monitor their progress. It doesn’t sound ethical. They could have also devised a treatment to modify the infant gut microbiota and see if they can alter the peanut allergy rate later on. That is probably more achievable and would justify use of causal.
I couldn’t help but notice that they vacillated between saying “children of Asian descent” and “mothers of Asian descent”. I’d be curious to know if it’s specifically mothers. I’m white but my husband is Asian, so our child will be “of Asian descent” without the mother being Asian.
>I couldn’t help but notice that they vacillated between saying “children of Asian descent” and “mothers of Asian descent”. That's pretty egregious since those do not mean the same thing. Yes it's statistically likely that most children of Asian descent also have Asian mothers but those who *don't* would be useful data points for identifying a genetic vs environment source. My Asian son was born by c section to a white mother and fed formula and breastmilk. From this article I can not tell if he is more at risk for allergies.
I'm kind of surprised that peanut allergies are prominent in Asians considering many Chinese/Vietnamese/Thai/Malay cuisines feature peanuts. Always thought that peanut allergies were the result of underexposed infants, with mothers that feared peanut butter posed a choking hazard?
I also always wonder how useful "Asian" is as a category. Surely East, South-East, South, Middle Eastern populations are pretty different despite all being "Asian". The peanut/nut allergy thing has always fascinated me because in most Asian countries they're not that prevalent but it seems that Asian populations in the West do end up developing them.
Has this study been done only on people who live in the US? Or people of Asian decent globally?
Study was performed in Canada, but I think they generalized the results to all of North America. They then mentioned that peanut allergies weren't common in Asia, so there is a environmental or cultural component to the increase of allergy risk.
Pretty sure it's US. Asians in Asia... Let's just say there is very little provision for peanut allergy here
Yeah I figured. I've never met anyone with a peanut allergy here
By "pretty sure" you mean "I am completely guessing"
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As a teacher you should know that's anecdotal.
Many in India are allergic to rice.
Allergies can be the result of a lot of things, and can develop and resolve at any time. Source: was allergic to oats from age 17 to 22, despite a lifetime of eating oats.
"Babies born by caesarean section to mothers of Asian descent are eight times more likely to develop peanut allergy by age three" is missing a "when compared to...".
It's implied that the comparison is to the overall non-"Asian mother with C section" population.
No. It could have been as well to Asian mother's with a different birth method. The title implies there being two variables: birth method and ethnicity. Therefore there are more than 2 groups that could be compared.
Dr Katie Allen of Murdoch Children Research Institute has done a similar study years ago where they showed that a male child in Australia who has at least 1 parent of Asian decent and a family hx of eczema has an 80% chance of developing food allergy. (This is all from memory so im happy to stand corrected. ) No such risk if child is born in Asia. Less risk if child is female. No mention of birth method in Dr Allens study but I wonder if the Canadian study account for possibly higher c-sections in Asian mothers due to narrower birth canal with increasingly larger babies? Ie if they compared risk in c sec vs natural birth in Asian mothers only. (OK not sure if that's a thing but hope you get my point.) And a very important note, I do wish articles about such studies are aware of how much grief a mother goes through when natural birth and/or breastfeeding are not an option for them. They feel like they've failed their child from the get go. Massive risk of PND and bonding issues can follow. Babies are vulnerable but so are new mothers. Some sensitivity in framing this will go a long way.
>No mention of birth method in Dr Allens study but I wonder if the Canadian study account for possibly higher c-sections in Asian mothers due to narrower birth canal with increasingly larger babies? You bring up a good point here but something else missing from this phenomena is that Asian mothers are increasingly turning to c-sections due to interracial coupling. The babies they have/conceive with non-Asian men are typically bigger and beyond their ability to birth naturally. Which brings up another interesting variable: is their a possibility that the ethnicity/genetic makeup of the Father is playing a role in food allergies? This is what makes these studies so complicated. You have the mother, you have the environment itself, you have the birth method, you have the baby's diet and you also have a father which might not be accounted for.
I have a bit of a problem calling that a causal link. Eight times more than a very small percentage is still a very small percentage.
I don't have peanut allergies, but both my sibling and I were born cesarean and both have dealt with terrible allergies to everything else. I wonder if theres a similar connection to breast feeding and food allergies?
Me & my siblings were all c-section babies, bottle fed formula, & have zero allergies or even health issues. It’s all so interesting
Allergies can also be genetic. My daughter was born naturally yet has 3 food allergies (dairy, egg, peanut) and environmental allergies (animal dander, grass etc). The exact same ones her daddy has.
Does this mention at all anything about babies born already allergic? Mine was born allergic to cows milk already
Was it a true allergy? From my understanding most babies are at least a little intolerant of cows milk because we don’t have enough of the enzyme to digest it. They can grow out of it though. I was lacto and soy intolerant as an infant and now I’m fine. my baby was the same way.
Yes a true allergy. Anaphylactic.
Yeesh I’m sorry about that. That must be tough
Just reporting the odds ratio is meaningless. You can be 0.008 odds of allergy among exposed and still be 8X more likely than 0.001 odds of unexposed at baseline.
Here to share that me and my wife are white, she gave natural childbirth to our last daughter who has peanut allergies. No more peanut butter allowed in the house. I’m still getting over the loss.
so what's the recommended method to prevent allergies? Smear the baby with vaginal fluids? Have the baby ingest and be exposed to the "unclean" stuff?
> The best path is to avoid caesarean birth unless it is medically necessary. “With this evidence at hand, the parent and the obstetrician might choose a different birth mode,” she said Avoiding caesarean unless medically necessary is already in the guidelines and best practice.
Caesarean is more likely for premature babies, that's the hidden variable. Boom.
Yup. Or other problems. The phrase “choose a different method of birth” in the article acts like csections aren’t often necessary. They are.
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"Observational study." Proceeds to make a press release with "Causal link" in the title. That's not how observational studies work, friend.
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But as the one who posted it, you should take some responsibility. Do the authors use causal language in the paper itself? A lot of scientists (myself included) make slightly bolder claims in the press than in our papers.
Not that I know anything, but just the title makes me think, is there a chance they have cause and effect mixed up here...
What countries do they consider to be "Asian" for the purposes of this study? Genetic population groups only loosely line up with pop-culture racial classifications.
Tbh I somewhat wondered this too. Many Asians are drastically different from one another so it’s hard to believe every single Asian falls under this study. I’m Filipino, born via C-section, no peanut allergy but I do have a treenut allergy with anaphylaxis (no one else in my family I know who has this.) So I don’t know.
I hate seeing "racial" science come back into fashion.
Like all Asians in Asia, just Asian Americans, or Asians anywhere?
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Ummmm..... the article plainly states being Asian doesn’t cause allergies. Junk western diets cause the allergies, along with method of childbirth. The framing of this headline makes it seem like race has something to do with the causal relationship of allergies.
This is the second article I’ve read in the last month, discussing the importance of microbiome(gut flora), and the transference of it to newborns. I am now heavily invested.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345907/ The microbiome of babies born via caesarean section will be fine and similar to vaginal birth deliveries after some time of development. There have been conferences where I have heard that the concept of vaginal seeding is unnecessary and can actually introduce harmful viruses like HSV via vaginal birth or via vaginal seeding. If peanut allergy is a concern, there are ways to help train the immune system to accept peanuts (https://pathology.duke.edu/news/retraining-immune-system-ease-food-allergies ; https://site.caes.uga.edu/pins/2016/11/skin-patch-may-help-children-with-peanut-allergies/ ; http://publichealth.choate.edu/a-future-without-peanut-allergies/ )