16 ms·

Impact of breast milk on IQ, brain size and white matter development (2010)

169 points by lainon 9y ago

c3534l 9y ago
I'm not sure why this study from 7 years ago is being dug up because it's not a particularly good, interesting, or definitive study. Some problems with it: 1. Small sample sizes. 2. Significance was only found in one subset of the population. Given enough ways to divide up groups of people, you will almost always get false positives. 3. Not an experimental design. 4. The study did not control for simple factors like income or the health of the parent.
- samat 9y ago
  2. Is explained in the abstract, all other issues are legitimate, though.
- petters 9y ago
  > this study from 7 years ago is being dug up That is not fair. You're making it sound like it's a JS framework. Seven years is nothing in this case.
  - dublinclontarf 9y ago
    I suppose the point being made is that enough time has passed for the study to have been properly validated; as the parent comment points out, lots of issues have been found with it.
    - lostcolony 9y ago
      That, and the fact it then isn't newsworthy. A single data point isn't science. It -might- be news, if it was a super recent data point (though, obviously, requires peer review and replication). This is neither.
      - ColanR 9y ago
        Old stuff is reposted here all the time. If it's interesting to the HN community, it's news.
    - jfaucett 9y ago
      > as the parent comment points out, lots of issues have been found with it. I'm not familiar with the research here so I can't say either way. But a preliminary google scholar search turned up a lot of articles which seem to suggest that breastfeeding has a bunch of positive impacts on numerous intelligence and general well-being metrics. The article itself has been cited 209 times according to google scholar [1], and this study [2] (cited 400+ some odd times) seems to accept some of the propositions made in this paper as givens. Anyway, I think it would have been interesting if the null hypotheses here weren't rejected. I kind of expect evolution to have optimized human breastmilk over alternatives for infant development. 1. https://scholar.google.com/scholar?cites=15094195751510081699&as_sdt=2005&sciodt=0,5&hl=en https://scholar.google.com/scholar?cites=1509419575151008169... 2. http://pediatrics.aappublications.org/content/129/3/e827.short http://pediatrics.aappublications.org/content/129/3/e827.sho...
      - deleted 9y ago
        [deleted]
- dalbasal 9y ago
  Our study also helps provide a framework for future mechanistic studies on I realize that repeat studies are important generally in science. But, many studies (particularly health related) seem to have such a result built into their design. If you get a result, it will just be preliminary and require a larger sample study moving on. Is there a mechanism in science for actually taking these preliminary results and validating/falsifying them more conclusively? Does a result like this make a larger scale study this team's top priority for the next study? Will these results convince another team to do the full study? Otherwise, it feels like there's something structurally wrong. If the study is designed as a non-conclusive prototype or framework, what's the point unless it leads to other studies?
  - m12k 9y ago
    I wish there was a sort of Snopes/Politifact/Rotten Tomatoes for science - an independent body that queried the top scientists in each field, and used this to quantitatively map the current state of the art and the consensus (or lack thereof) around that field's theories. Instead of e.g. 'the current state of CRISPR research' or 'P vs NP' being something that lived implicitly in the minds of the few researchers that keep up to date with all the relevant papers, it could be explicit on the site for all to see (including journalists, who would finally have an easy way to avoid putting their foot in their mouth with another 'Scientists show that lung cancer causes smoking!' headline). Even if all that could be said in a given area was 'Correlation has been shown, causation has not, a study is underway to try to establish this, and 60% of randomly queried researchers in the area believe causation will be proven' then that would still be super valuable. The result "99% of climate researchers and meteorologists believe climate change to be manmade" is a great result, but it would be much more hard-hitting if it came from an institution that was already considered to be reliable.
    - ever1 9y ago
      This mechanism already exists in some way with top journals and peer-reviewing. Their credibility relies on their capability to select the most important and proven papers.
- DangerousPie 9y ago
  I agree this is a weak, small study but I'm not sure I agree with your point 4. Obviously this all depends on having a large-enough sample size to start with, but if the groups are properly randomized they shouldn't have to control for income/health of parents (since it's not correlated with the independent variable). I'm also not sure what you mean by #3.
  - ballenf 9y ago
    > In the trial of interest here, mothers elected to breastfeed but varied in their success in expressing milk and, therefore, in the need for supplementary feeding. According to randomisation before breastfeeding commenced, these infants were given one of three supplements: a nutrient enriched preterm formula (PTF), a standard term formula (TF; used in the 1980s for feeding preterm infants) or banked breast milk (BBM; provided by unrelated donors and unfortified). Since the mothers self-selected breastfeeding, the study makes the assumption that banked breast milk (from a random donor) is equivalent to fresh milk from the mother. It assumes that the act of suckling on the mother's breast has no bearing on brain development. See recent evidence regard pre-term babies and skin contact: http://handtohold.org/resources/helpful-articles/the-benefits-of-kangaroo-care/ http://handtohold.org/resources/helpful-articles/the-benefit... Finally, it ignores other (more recent) studies showing how the mother's milk reacts to signals from the baby's saliva (backwash from baby sucked back into breast). https://www.sciencenews.org/blog/growth-curve/backwash-nursing-babies-may-trigger-infection-fighters https://www.sciencenews.org/blog/growth-curve/backwash-nursi... (Not saying these links aren't equally or more flawed, but it's avenues of causation ignored.) Wouldn't a valid study require randomized instruction to mothers about whether to breastfeed? Is that ethical? Compliance is equally tough: breastfeeding can be incredibly difficult for some moms/babies. Further, couldn't the difficulty in breastfeeding also be correlated to the effects -- could children reject breastmilk based on the mother's health or otherwise based on the "quality" of the milk? Please forgive if I'm asking questions that are well understood -- by no means am I claiming to be knowledgeable in this field. But I do have kids and went through hell with one of them on this, so I'm very interested in the research.
- alexandercrohde 9y ago
  It's not clear to me why you are picking at the mechanics here. Are you arguing a different study that shows the same thing should be substituted? Because it's my understanding that the evidence shows a breastmilk->IQ correlation as well as all the other health benefits [https://en.wikipedia.org/wiki/Breastfeeding#Baby https://en.wikipedia.org/wiki/Breastfeeding#Baby]
- slededit 9y ago
  Complaints about small sample sizes are practically a stock answer at this point. I've never seen a study posted that didn't have this complaint. It would be much more useful to talk about the statistical significance in more quantitative terms.
sbenitoj 9y ago
What's amazing is that people even feel the need to study whether breastmilk is superior to processed alternatives -- would a zoologist ever recommend baby mammals receive any food other than their mother's milk to facilitate optimal development? Why do humans think they're any different?
- std_throwaway 9y ago
  Nature "learns" by trial and error while humans have the capacity to reason about things. In the long run intellect will win (although in most cases we are far far from that point).
  - coldtea 9y ago
    >In the long run intellect will win Citation needed. What's even more possible is that in the long run nature will win -- it is a far more powerful force than intellect. In the very least, let's see how intellect fares against the heat death of the universe...
    - dmichulke 9y ago
      I think GP means to that for many problems, the time span for finding a local optimum in an evolutionary way ("nature") is longer than in a scientific way ("human trial and error + reasoning"). Of course, there are probably species that burn through a few generations per hour but these are not really suited to solving problems that mammals can.
      - coldtea 9y ago
        >I think GP means to that for many problems, the time span for finding a local optimum in an evolutionary way ("nature") is longer than in a scientific way ("human trial and error + reasoning"). For some problems regarding the functioning of living things yes, but for other problems evolution doesn't apply, and nature (aka the universe) can "strike" before science had the time to find anything to protect against them (e.g. a meteor hit). And for other problems still, science might be the one that created them (e.g. nuclear annihilation, global warming, etc). >Of course, there are probably species that burn through a few generations per hour but these are not really suited to solving problems that mammals can. No, but some of them could e.g. mutate and kill all humans or enough to destroy civilization.
deleted 9y ago
[deleted]
epx 9y ago
Well, I had none of this breast milk stuff, poor me!!
- coldtea 9y ago
  And who said it didn't have an impact?
- libeclipse 9y ago
  Sample_size = 1;
- fgjjgutjvnu 9y ago
  And here you are on HN... (SCNR)
rayiner 9y ago
This study does not control for maternal IQ or socio-economic status. Later studies show that much of the link between breastfeeding and cognitive development is due to confounding effects (in particular, higher SES mothers are more likely to breastfeed): http://bmjopen.bmj.com/content/3/8/e003259 http://bmjopen.bmj.com/content/3/8/e003259 > Conclusions Much of the reported effect of breastfeeding on child neurodevelopment is due to confounding. It is unlikely that additional work will change the current synthesis. Future studies should attempt to rigorously control for all important confounders. Alternatively, study designs using sibling cohorts discordant for breastfeeding may yield more robust conclusions. See also: http://pediatrics.aappublications.org/content/early/2017/03/23/peds.2016-1848 http://pediatrics.aappublications.org/content/early/2017/03/... > RESULTS: Before matching, breastfeeding was associated with better development on almost every outcome. After matching and adjustment for multiple testing, only 1 of the 13 outcomes remained statistically significant: children’s hyperactivity (difference score, –0.84; 95% confidence interval, –1.33 to –0.35) at age 3 years for children who were breastfed for at least 6 months. No statistically significant differences were observed postmatching on any outcome at age 5 years. The linked study also yields some odd results: > In the total group %EBM correlated significantly with Verbal IQ (VIQ); in boys, with all IQ scores, TBV and WMV. VIQ was, in turn, correlated with WMV and, in boys only, additionally with TBV. No significant relationships were seen in girls or with grey matter. A meta-study that adjusted for maternal IQ only (but not socioeconomic status, which independently correlates with higher rates of breastfeeding) found a very small effect on IQ: https://www.ncbi.nlm.nih.gov/pubmed/26211556 https://www.ncbi.nlm.nih.gov/pubmed/26211556 > We included 17 studies with 18 estimates of the relationship between breastfeeding and performance in intelligence tests. In a random-effects model, breastfed subjects achieved a higher IQ [mean difference: 3.44 points (95% confidence interval: 2.30; 4.58)]. We found no evidence of publication bias. Studies that controlled for maternal IQ showed a smaller benefit from breastfeeding [mean difference 2.62 points (95% confidence interval: 1.25; 3.98)]. In the meta-regression, none of the study characteristics explained the heterogeneity among the studies.
- dm319 9y ago
  Yep, there are no good experimental designs for breastmilk that are also ethically ok. What is really interesting about this study is that it is based on a a cohort of pre-term babies in randomised and blinded study from the 1980s [1] - where they randomised between formula and donor breast milk. You can read the conclusions easily from the link, but essentially the donor breast milk fed babies did far worse than the formula fed ones, both overall and in subset analysis. Their conclusion is that preterm babies are in need of adequate nutrition, and, reading between the lines, donor breast milk does not provide this. Where the paper gets confusing is when we start to look at the analysis of the mother's breast milk, which occurred in a follow-up study in the 90s [2]. Of course, this was not randomised, and was parental choice. The 90s paper showed a significantly higher IQ in those fed with mother's breast milk. I say this is confusing because the later papers mention that the trial is randomised (the result of which showed a negative effect for breast milk, albeit donor), while they are actually comparing two groups in an observational study (mother's breast milk vs not). So actually, we go back to the usual 'can we correct for everything' in an observational study? We should be very cautious drawing conclusions from observational studies - there are nice examples of these studies showing the exact opposite of the randomised study - for example in this trial which set out to show anti-oxidants prevented cancer [3], they managed to show simultaneously that the obversational findings directly contradicted the randomised findings. A better study is the cluster-randomised study [4] in Belarus, but even this study has many flaws - it was cluster-randomised, those randomised to receive teaching on the benefits of breast milk also received a lot more input and support from their midwives and hospitals in general. There was a significant difference in IQ between groups, though the measurement was not blinded. There was a trend, but no significance in the difference between teachers rating of the groups. Another study looking at sibling pairs didn't find a difference between siblings who had and hadn't been breastfed - this is still an observational study, but being siblings it controls for a few more things. [5] Anyway, there are lots of issues in breast-feeding research. Another is comparing 1st to 3rd world, where other issues, particularly infection risk becomes important. Formula milk contains iron, which is pretty important in cognitive development. Breast milk does not contain any. This may have been an evolved mechanism to protect from infections, given that (almost) all infections require ready access to iron, and may explain the increased risk of serious infections in 3rd world countries. To sum up, I don't personally believe there is good enough evidence to recommend breast feeding over formula feeding. For a parent it should come down to individual situations. Our first child was slightly micrognathic, which made breast feeding very painful. In retrospect we pursued breast feeding for far too long, and it was causing stress in both mother and child, which I doubt is beneficial to psychological health. Our second kid would only take breast and was easy to feed. Our third took breast without a problem, but was left hungry so needed topped up with formula. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1792630/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1792630/ [2] https://www.ncbi.nlm.nih.gov/pubmed/1346280 https://www.ncbi.nlm.nih.gov/pubmed/1346280 [3] https://www.ncbi.nlm.nih.gov/pubmed/8127329 https://www.ncbi.nlm.nih.gov/pubmed/8127329 [4] https://www.ncbi.nlm.nih.gov/pubmed/18458209 https://www.ncbi.nlm.nih.gov/pubmed/18458209 [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633819/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633819/
d--b 9y ago
Seriously, stats on 26 boys...
JackC 9y ago
As a recent parent I would love it if there was more realistic health information for parents about the benefits of breastfeeding. As best I can tell from metastudies (which I'm totally unqualified to read), the scientific answer right now is: there may be some effect, but if so it's too small to reliably measure and may be swamped by other interventions. (I could be wrong! That's why I want better info.) (Compare to, say, the advice to have infants sleep on their backs to prevent SIDS, or the HPV vaccine, which have clear and measurable health impacts at a population level.) This matters because breastfeeding has costs that tend to be ignored. Just from personal experience, it pushes disproportionate work onto my wife in a way that's hard to correct for and detracts from parenting. And given that she's working full time, it's also a huge investment of resources -- if you take her work time into account, we're spending tens or hundreds of dollars a day for this. And many women get injuries and infections, soldiering through months of agony for that health benefit that may or may not exist. Setting aside the health of the parents (and we shouldn't, that's an easy trap), breastfeeding uses a lot of resources that could go toward other interventions for the child. Maybe it's all worth it? But I wish there was a better conversation about the tradeoffs.
- Nokinside 9y ago
  You are talking about breastfeeding. The article talks about breast milk. In the case the distinction is not clear, many mothers use breast pumps. >WHO can now say with full confidence that breastfeeding reduces child mortality and has health benefits that extend into adulthood. On a population basis, exclusive breastfeeding for the first six months of life is the recommended way of feeding infants, followed by continued breastfeeding with appropriate complementary foods for up to two years or beyond. http://www.who.int/maternal_child_adolescent/topics/newborn/nutrition/breastfeeding/en/ http://www.who.int/maternal_child_adolescent/topics/newborn/...
  - Pharylon 9y ago
    The WHO isn't a great source for breast feeding, because of weird political and historical reasons. In the 1960s, Nestle started pushing formula hard in developing countries in Africa. And by "pushing," I mean they hired people to dress as nurses and tell women that they should use formula because it was healthier than breast milk. They also gave women free samples, knowing that if they used the samples in the beginning, the women would have a hard time getting their milk to come in later, "hooking" them on the formula. What made it worse is that the formula was very, very expensive to these people, and often didn't have any instructions printed in a language the mother could read (assuming they were even literate in any language), causing the formula to be routinely under-dosed. Oh, and they often didn't have access to safe drinking water, which is kind of important for formula. We don't know how many babies died because of Nestle's actions, but it was probably in the millions. This led to the huge Nestle formula boycott of the 70s. The WHO started pushing breast feeding hard, and created a whole panel to do it, made up of breast-feeding advocates who viewed it as a kind of panacea. That wouldn't have been a problem normally because strong believers in breastfeeding were probably needed to counteract the corporate push towards formula, but there was a big complication: AIDS. In 1981 the first cases of HIV transmission by breast milk were reported, and by the mid-80s, doctors knew for certain that HIV could be transmitted by breast feeding. But the breast-feeding advocates in the WHO wouldn't accept the facts. Even in the 90s the WHO was "debunking" that "myth" in their literature to third-world mothers. We don't know how many babies died because the WHO told HIV-positive mothers that they should breast feed, but it was probably in the millions. To this day, the WHO promotes breast-feeding heavily (which is fine, they should) but they play up the benefits of it more than is really scientifically defensible. Their breastfeeding outreach isn't run by impartial people, but by true-believers in the power of breastfeeding. So take their info with a grain of salt.
colordrops 9y ago
It's funny to me that everyone shits on Soylent and how obviously bad it is and yet needs a PhD to figure out if they should breastfeed instead of giving their newborn "formula". Have any of you looked at the ingredients in formula? It's garbage.
- spraak 9y ago
  That's a great analogy
- nollbit 9y ago
  Except the the science doesn't appear to support that. Read the thread.
- logfromblammo 9y ago
  Even George Costanza knows it's okay to eat garbage if it's on top.~ People in general are way too picky about what they shove down their gullets. It's just chemicals, and the chemicals in formula are close enough to natural milk that it won't kill fragile human babies. Likewise, the chemicals in Soylent are close enough to food that you can quaff it in lieu of eating. The only problem is determining which chemicals are actually important, which is somewhat difficult, because yadda yadda yadda unethical human experimentation.... But that wire-mom vs. cloth-mom monkey experiment should also suggest that there's more to breastfeeding than just nutrition.
mkempe 9y ago
Apart from claims of positive IQ impact, breastfeeding has many other proven benefits (as widely reported by WHO and in Sweden): "Breastfed children are at a lower risk of infections such as acute otitis, gastroenteritis, and respiratory tract infections. ... Women who have breastfed also receive health benefits through a somewhat reduced risk of developing breast and ovarian cancer and diabetes type 2."
eli 9y ago
Sightly offtopic, but recent or prospective parents on HN may appreciate the book "Expecting Better" by Emily Oster, which takes a critical economists eye to advice and studies about pregnancy. Sort of in the vein of Freakonomics.
all_usernames 9y ago
There are at this time 112 comments on this page. I searched for "emotion" and got zero hits, and only one comment mentioned "bonding." A problem with any scientific assessment of the human condition is the narrow focus, and these studies only take into account a few variables out of thousands. Emotional bonding between mother and child is a huge factor in breastfeeding -- that's common sense that doesn't require scientific validation, although it would be very interesting to see studies from that perspective.
- silencio 9y ago
  Parents that bottle feed (bm or formula) can still bond with their babies. I exclusively pump, and it made me really happy to see that my male partner was able to feed the baby and do a lot of skin-to-skin/holding time in the early days. I love cuddling with my kid too. Bottle didn't change that at all.
- rayiner 9y ago
  I'd call it handwaving rather than common sense. What does emotional bonding even mean? Are bottle fed children more emotionally distant and less clingy? Remember: in the 1970s, only 25% of children were ever breastfed. Are Gen X-ers emotionally distant compared to boomers and millenials?
  - watwut 9y ago
    I recall articles that say that current teenagers and young adults have closer relationships with their parents then previous generation. However, much more changed in the child raising then just breastfeeding.
cerealbad 9y ago
to all expectant mothers nervous about whether you should breast feed or not, it's definitely a huge and important decision, so i have devised an experiment you can undertake right now to try to gather more data so you can make an informed decision. ask your husband* to suck your nipple then gauge reaction, offer a favorite bottle as an alternative just to be sure. *results may be vary based on husband iq.

169 points by lainon 9y ago

I'm not sure why this study from 7 years ago is being dug up because it's not a particularly good, interesting, or definitive study. Some problems with it: 1. Small sample sizes. 2. Significance was only found in one subset of the population. Given enough ways to divide up groups of people, you will almost always get false positives. 3. Not an experimental design. 4. The study did not control for simple factors like income or the health of the parent.

samat 9y ago
2. Is explained in the abstract, all other issues are legitimate, though.
petters 9y ago
> this study from 7 years ago is being dug up That is not fair. You're making it sound like it's a JS framework. Seven years is nothing in this case.
- dublinclontarf 9y ago
  I suppose the point being made is that enough time has passed for the study to have been properly validated; as the parent comment points out, lots of issues have been found with it.
  - lostcolony 9y ago
    That, and the fact it then isn't newsworthy. A single data point isn't science. It -might- be news, if it was a super recent data point (though, obviously, requires peer review and replication). This is neither.
    - ColanR 9y ago
      Old stuff is reposted here all the time. If it's interesting to the HN community, it's news.
  - jfaucett 9y ago
    > as the parent comment points out, lots of issues have been found with it. I'm not familiar with the research here so I can't say either way. But a preliminary google scholar search turned up a lot of articles which seem to suggest that breastfeeding has a bunch of positive impacts on numerous intelligence and general well-being metrics. The article itself has been cited 209 times according to google scholar [1], and this study [2] (cited 400+ some odd times) seems to accept some of the propositions made in this paper as givens. Anyway, I think it would have been interesting if the null hypotheses here weren't rejected. I kind of expect evolution to have optimized human breastmilk over alternatives for infant development. 1. https://scholar.google.com/scholar?cites=15094195751510081699&as_sdt=2005&sciodt=0,5&hl=en https://scholar.google.com/scholar?cites=1509419575151008169... 2. http://pediatrics.aappublications.org/content/129/3/e827.short http://pediatrics.aappublications.org/content/129/3/e827.sho...
    - deleted 9y ago
      [deleted]
dalbasal 9y ago
Our study also helps provide a framework for future mechanistic studies on I realize that repeat studies are important generally in science. But, many studies (particularly health related) seem to have such a result built into their design. If you get a result, it will just be preliminary and require a larger sample study moving on. Is there a mechanism in science for actually taking these preliminary results and validating/falsifying them more conclusively? Does a result like this make a larger scale study this team's top priority for the next study? Will these results convince another team to do the full study? Otherwise, it feels like there's something structurally wrong. If the study is designed as a non-conclusive prototype or framework, what's the point unless it leads to other studies?
- m12k 9y ago
  I wish there was a sort of Snopes/Politifact/Rotten Tomatoes for science - an independent body that queried the top scientists in each field, and used this to quantitatively map the current state of the art and the consensus (or lack thereof) around that field's theories. Instead of e.g. 'the current state of CRISPR research' or 'P vs NP' being something that lived implicitly in the minds of the few researchers that keep up to date with all the relevant papers, it could be explicit on the site for all to see (including journalists, who would finally have an easy way to avoid putting their foot in their mouth with another 'Scientists show that lung cancer causes smoking!' headline). Even if all that could be said in a given area was 'Correlation has been shown, causation has not, a study is underway to try to establish this, and 60% of randomly queried researchers in the area believe causation will be proven' then that would still be super valuable. The result "99% of climate researchers and meteorologists believe climate change to be manmade" is a great result, but it would be much more hard-hitting if it came from an institution that was already considered to be reliable.
  - ever1 9y ago
    This mechanism already exists in some way with top journals and peer-reviewing. Their credibility relies on their capability to select the most important and proven papers.
DangerousPie 9y ago
I agree this is a weak, small study but I'm not sure I agree with your point 4. Obviously this all depends on having a large-enough sample size to start with, but if the groups are properly randomized they shouldn't have to control for income/health of parents (since it's not correlated with the independent variable). I'm also not sure what you mean by #3.
- ballenf 9y ago
  > In the trial of interest here, mothers elected to breastfeed but varied in their success in expressing milk and, therefore, in the need for supplementary feeding. According to randomisation before breastfeeding commenced, these infants were given one of three supplements: a nutrient enriched preterm formula (PTF), a standard term formula (TF; used in the 1980s for feeding preterm infants) or banked breast milk (BBM; provided by unrelated donors and unfortified). Since the mothers self-selected breastfeeding, the study makes the assumption that banked breast milk (from a random donor) is equivalent to fresh milk from the mother. It assumes that the act of suckling on the mother's breast has no bearing on brain development. See recent evidence regard pre-term babies and skin contact: http://handtohold.org/resources/helpful-articles/the-benefits-of-kangaroo-care/ http://handtohold.org/resources/helpful-articles/the-benefit... Finally, it ignores other (more recent) studies showing how the mother's milk reacts to signals from the baby's saliva (backwash from baby sucked back into breast). https://www.sciencenews.org/blog/growth-curve/backwash-nursing-babies-may-trigger-infection-fighters https://www.sciencenews.org/blog/growth-curve/backwash-nursi... (Not saying these links aren't equally or more flawed, but it's avenues of causation ignored.) Wouldn't a valid study require randomized instruction to mothers about whether to breastfeed? Is that ethical? Compliance is equally tough: breastfeeding can be incredibly difficult for some moms/babies. Further, couldn't the difficulty in breastfeeding also be correlated to the effects -- could children reject breastmilk based on the mother's health or otherwise based on the "quality" of the milk? Please forgive if I'm asking questions that are well understood -- by no means am I claiming to be knowledgeable in this field. But I do have kids and went through hell with one of them on this, so I'm very interested in the research.
alexandercrohde 9y ago
It's not clear to me why you are picking at the mechanics here. Are you arguing a different study that shows the same thing should be substituted? Because it's my understanding that the evidence shows a breastmilk->IQ correlation as well as all the other health benefits [https://en.wikipedia.org/wiki/Breastfeeding#Baby https://en.wikipedia.org/wiki/Breastfeeding#Baby]
slededit 9y ago
Complaints about small sample sizes are practically a stock answer at this point. I've never seen a study posted that didn't have this complaint. It would be much more useful to talk about the statistical significance in more quantitative terms.

sbenitoj 9y ago

What's amazing is that people even feel the need to study whether breastmilk is superior to processed alternatives -- would a zoologist ever recommend baby mammals receive any food other than their mother's milk to facilitate optimal development? Why do humans think they're any different?

std_throwaway 9y ago
Nature "learns" by trial and error while humans have the capacity to reason about things. In the long run intellect will win (although in most cases we are far far from that point).
- coldtea 9y ago
  >In the long run intellect will win Citation needed. What's even more possible is that in the long run nature will win -- it is a far more powerful force than intellect. In the very least, let's see how intellect fares against the heat death of the universe...
  - dmichulke 9y ago
    I think GP means to that for many problems, the time span for finding a local optimum in an evolutionary way ("nature") is longer than in a scientific way ("human trial and error + reasoning"). Of course, there are probably species that burn through a few generations per hour but these are not really suited to solving problems that mammals can.
    - coldtea 9y ago
      >I think GP means to that for many problems, the time span for finding a local optimum in an evolutionary way ("nature") is longer than in a scientific way ("human trial and error + reasoning"). For some problems regarding the functioning of living things yes, but for other problems evolution doesn't apply, and nature (aka the universe) can "strike" before science had the time to find anything to protect against them (e.g. a meteor hit). And for other problems still, science might be the one that created them (e.g. nuclear annihilation, global warming, etc). >Of course, there are probably species that burn through a few generations per hour but these are not really suited to solving problems that mammals can. No, but some of them could e.g. mutate and kill all humans or enough to destroy civilization.

deleted 9y ago

[deleted]

epx 9y ago

Well, I had none of this breast milk stuff, poor me!!

coldtea 9y ago
And who said it didn't have an impact?
libeclipse 9y ago
Sample_size = 1;
fgjjgutjvnu 9y ago
And here you are on HN... (SCNR)

rayiner 9y ago

This study does not control for maternal IQ or socio-economic status. Later studies show that much of the link between breastfeeding and cognitive development is due to confounding effects (in particular, higher SES mothers are more likely to breastfeed): http://bmjopen.bmj.com/content/3/8/e003259 http://bmjopen.bmj.com/content/3/8/e003259 > Conclusions Much of the reported effect of breastfeeding on child neurodevelopment is due to confounding. It is unlikely that additional work will change the current synthesis. Future studies should attempt to rigorously control for all important confounders. Alternatively, study designs using sibling cohorts discordant for breastfeeding may yield more robust conclusions. See also: http://pediatrics.aappublications.org/content/early/2017/03/23/peds.2016-1848 http://pediatrics.aappublications.org/content/early/2017/03/... > RESULTS: Before matching, breastfeeding was associated with better development on almost every outcome. After matching and adjustment for multiple testing, only 1 of the 13 outcomes remained statistically significant: children’s hyperactivity (difference score, –0.84; 95% confidence interval, –1.33 to –0.35) at age 3 years for children who were breastfed for at least 6 months. No statistically significant differences were observed postmatching on any outcome at age 5 years. The linked study also yields some odd results: > In the total group %EBM correlated significantly with Verbal IQ (VIQ); in boys, with all IQ scores, TBV and WMV. VIQ was, in turn, correlated with WMV and, in boys only, additionally with TBV. No significant relationships were seen in girls or with grey matter. A meta-study that adjusted for maternal IQ only (but not socioeconomic status, which independently correlates with higher rates of breastfeeding) found a very small effect on IQ: https://www.ncbi.nlm.nih.gov/pubmed/26211556 https://www.ncbi.nlm.nih.gov/pubmed/26211556 > We included 17 studies with 18 estimates of the relationship between breastfeeding and performance in intelligence tests. In a random-effects model, breastfed subjects achieved a higher IQ [mean difference: 3.44 points (95% confidence interval: 2.30; 4.58)]. We found no evidence of publication bias. Studies that controlled for maternal IQ showed a smaller benefit from breastfeeding [mean difference 2.62 points (95% confidence interval: 1.25; 3.98)]. In the meta-regression, none of the study characteristics explained the heterogeneity among the studies.

dm319 9y ago
Yep, there are no good experimental designs for breastmilk that are also ethically ok. What is really interesting about this study is that it is based on a a cohort of pre-term babies in randomised and blinded study from the 1980s [1] - where they randomised between formula and donor breast milk. You can read the conclusions easily from the link, but essentially the donor breast milk fed babies did far worse than the formula fed ones, both overall and in subset analysis. Their conclusion is that preterm babies are in need of adequate nutrition, and, reading between the lines, donor breast milk does not provide this. Where the paper gets confusing is when we start to look at the analysis of the mother's breast milk, which occurred in a follow-up study in the 90s [2]. Of course, this was not randomised, and was parental choice. The 90s paper showed a significantly higher IQ in those fed with mother's breast milk. I say this is confusing because the later papers mention that the trial is randomised (the result of which showed a negative effect for breast milk, albeit donor), while they are actually comparing two groups in an observational study (mother's breast milk vs not). So actually, we go back to the usual 'can we correct for everything' in an observational study? We should be very cautious drawing conclusions from observational studies - there are nice examples of these studies showing the exact opposite of the randomised study - for example in this trial which set out to show anti-oxidants prevented cancer [3], they managed to show simultaneously that the obversational findings directly contradicted the randomised findings. A better study is the cluster-randomised study [4] in Belarus, but even this study has many flaws - it was cluster-randomised, those randomised to receive teaching on the benefits of breast milk also received a lot more input and support from their midwives and hospitals in general. There was a significant difference in IQ between groups, though the measurement was not blinded. There was a trend, but no significance in the difference between teachers rating of the groups. Another study looking at sibling pairs didn't find a difference between siblings who had and hadn't been breastfed - this is still an observational study, but being siblings it controls for a few more things. [5] Anyway, there are lots of issues in breast-feeding research. Another is comparing 1st to 3rd world, where other issues, particularly infection risk becomes important. Formula milk contains iron, which is pretty important in cognitive development. Breast milk does not contain any. This may have been an evolved mechanism to protect from infections, given that (almost) all infections require ready access to iron, and may explain the increased risk of serious infections in 3rd world countries. To sum up, I don't personally believe there is good enough evidence to recommend breast feeding over formula feeding. For a parent it should come down to individual situations. Our first child was slightly micrognathic, which made breast feeding very painful. In retrospect we pursued breast feeding for far too long, and it was causing stress in both mother and child, which I doubt is beneficial to psychological health. Our second kid would only take breast and was easy to feed. Our third took breast without a problem, but was left hungry so needed topped up with formula. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1792630/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1792630/ [2] https://www.ncbi.nlm.nih.gov/pubmed/1346280 https://www.ncbi.nlm.nih.gov/pubmed/1346280 [3] https://www.ncbi.nlm.nih.gov/pubmed/8127329 https://www.ncbi.nlm.nih.gov/pubmed/8127329 [4] https://www.ncbi.nlm.nih.gov/pubmed/18458209 https://www.ncbi.nlm.nih.gov/pubmed/18458209 [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633819/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633819/

d--b 9y ago

Seriously, stats on 26 boys...

JackC 9y ago

As a recent parent I would love it if there was more realistic health information for parents about the benefits of breastfeeding. As best I can tell from metastudies (which I'm totally unqualified to read), the scientific answer right now is: there may be some effect, but if so it's too small to reliably measure and may be swamped by other interventions. (I could be wrong! That's why I want better info.) (Compare to, say, the advice to have infants sleep on their backs to prevent SIDS, or the HPV vaccine, which have clear and measurable health impacts at a population level.) This matters because breastfeeding has costs that tend to be ignored. Just from personal experience, it pushes disproportionate work onto my wife in a way that's hard to correct for and detracts from parenting. And given that she's working full time, it's also a huge investment of resources -- if you take her work time into account, we're spending tens or hundreds of dollars a day for this. And many women get injuries and infections, soldiering through months of agony for that health benefit that may or may not exist. Setting aside the health of the parents (and we shouldn't, that's an easy trap), breastfeeding uses a lot of resources that could go toward other interventions for the child. Maybe it's all worth it? But I wish there was a better conversation about the tradeoffs.

Nokinside 9y ago
You are talking about breastfeeding. The article talks about breast milk. In the case the distinction is not clear, many mothers use breast pumps. >WHO can now say with full confidence that breastfeeding reduces child mortality and has health benefits that extend into adulthood. On a population basis, exclusive breastfeeding for the first six months of life is the recommended way of feeding infants, followed by continued breastfeeding with appropriate complementary foods for up to two years or beyond. http://www.who.int/maternal_child_adolescent/topics/newborn/nutrition/breastfeeding/en/ http://www.who.int/maternal_child_adolescent/topics/newborn/...
- Pharylon 9y ago
  The WHO isn't a great source for breast feeding, because of weird political and historical reasons. In the 1960s, Nestle started pushing formula hard in developing countries in Africa. And by "pushing," I mean they hired people to dress as nurses and tell women that they should use formula because it was healthier than breast milk. They also gave women free samples, knowing that if they used the samples in the beginning, the women would have a hard time getting their milk to come in later, "hooking" them on the formula. What made it worse is that the formula was very, very expensive to these people, and often didn't have any instructions printed in a language the mother could read (assuming they were even literate in any language), causing the formula to be routinely under-dosed. Oh, and they often didn't have access to safe drinking water, which is kind of important for formula. We don't know how many babies died because of Nestle's actions, but it was probably in the millions. This led to the huge Nestle formula boycott of the 70s. The WHO started pushing breast feeding hard, and created a whole panel to do it, made up of breast-feeding advocates who viewed it as a kind of panacea. That wouldn't have been a problem normally because strong believers in breastfeeding were probably needed to counteract the corporate push towards formula, but there was a big complication: AIDS. In 1981 the first cases of HIV transmission by breast milk were reported, and by the mid-80s, doctors knew for certain that HIV could be transmitted by breast feeding. But the breast-feeding advocates in the WHO wouldn't accept the facts. Even in the 90s the WHO was "debunking" that "myth" in their literature to third-world mothers. We don't know how many babies died because the WHO told HIV-positive mothers that they should breast feed, but it was probably in the millions. To this day, the WHO promotes breast-feeding heavily (which is fine, they should) but they play up the benefits of it more than is really scientifically defensible. Their breastfeeding outreach isn't run by impartial people, but by true-believers in the power of breastfeeding. So take their info with a grain of salt.

colordrops 9y ago

It's funny to me that everyone shits on Soylent and how obviously bad it is and yet needs a PhD to figure out if they should breastfeed instead of giving their newborn "formula". Have any of you looked at the ingredients in formula? It's garbage.

spraak 9y ago
That's a great analogy
nollbit 9y ago
Except the the science doesn't appear to support that. Read the thread.
logfromblammo 9y ago
Even George Costanza knows it's okay to eat garbage if it's on top.~ People in general are way too picky about what they shove down their gullets. It's just chemicals, and the chemicals in formula are close enough to natural milk that it won't kill fragile human babies. Likewise, the chemicals in Soylent are close enough to food that you can quaff it in lieu of eating. The only problem is determining which chemicals are actually important, which is somewhat difficult, because yadda yadda yadda unethical human experimentation.... But that wire-mom vs. cloth-mom monkey experiment should also suggest that there's more to breastfeeding than just nutrition.

mkempe 9y ago

Apart from claims of positive IQ impact, breastfeeding has many other proven benefits (as widely reported by WHO and in Sweden): "Breastfed children are at a lower risk of infections such as acute otitis, gastroenteritis, and respiratory tract infections. ... Women who have breastfed also receive health benefits through a somewhat reduced risk of developing breast and ovarian cancer and diabetes type 2."

eli 9y ago

Sightly offtopic, but recent or prospective parents on HN may appreciate the book "Expecting Better" by Emily Oster, which takes a critical economists eye to advice and studies about pregnancy. Sort of in the vein of Freakonomics.

all_usernames 9y ago

There are at this time 112 comments on this page. I searched for "emotion" and got zero hits, and only one comment mentioned "bonding." A problem with any scientific assessment of the human condition is the narrow focus, and these studies only take into account a few variables out of thousands. Emotional bonding between mother and child is a huge factor in breastfeeding -- that's common sense that doesn't require scientific validation, although it would be very interesting to see studies from that perspective.

silencio 9y ago
Parents that bottle feed (bm or formula) can still bond with their babies. I exclusively pump, and it made me really happy to see that my male partner was able to feed the baby and do a lot of skin-to-skin/holding time in the early days. I love cuddling with my kid too. Bottle didn't change that at all.
rayiner 9y ago
I'd call it handwaving rather than common sense. What does emotional bonding even mean? Are bottle fed children more emotionally distant and less clingy? Remember: in the 1970s, only 25% of children were ever breastfed. Are Gen X-ers emotionally distant compared to boomers and millenials?
- watwut 9y ago
  I recall articles that say that current teenagers and young adults have closer relationships with their parents then previous generation. However, much more changed in the child raising then just breastfeeding.

cerealbad 9y ago

to all expectant mothers nervous about whether you should breast feed or not, it's definitely a huge and important decision, so i have devised an experiment you can undertake right now to try to gather more data so you can make an informed decision. ask your husband* to suck your nipple then gauge reaction, offer a favorite bottle as an alternative just to be sure. *results may be vary based on husband iq.