Do breastfed children have higher IQs? The answer is annoyingly hard to uncover
stuartritchie.substack.com
stuartritchie.substack.com
The analysis presented here seems convincing in the sense that we don’t have good evidence that breastfeeding increases IQ. But from what I remember there is good evidence that it improves the baby’s immune system among many other things.
So bottom line is in the absence of massive amounts of strong evidence against breastfeeding, by default you should favour it. And if in the end the IQ effect isn’t real at least you improved your baby’s health (and hence survival chances). If you have the option to breastfeed, go for it.
And as the article stated, if for whatever reason you cannot or will not you probably don’t need to feel too bad about it because the effects while positive are at the margin to the best of our current knowledge and formula is getting better every decade.
Losing that flexibility would be worthwhile only if there was strong evidence that breastfeeding had advantages that can’t be replicated with formula. On that front it should be noted that the vast majority of GenX and older millennials were formula fed, as breastfeeding rates plummeted in the 1970s and 1980s. If there was a massive impact from that it would have been apparent.
And finally, I think it's incredibly selfish to argue about equitably splitting feeding times, at the likely expense of your child's health and growth.
Young adults and men seem to be less healthy than ever. Plummeting testosterone, crazy rates of allergies, increased suicide rates, high depression.... But your right, if feeding them processed junk was bad, we'd see signs of it by now.
Young adults and men are less healthy than ever because we play on our computers instead of tilling soil and fighting in wars.
It is associated with less GI infections, ear infections, asthma, lower blood pressure, lower cholesterol and risk of type 2 diabetes.
1. https://www.researchgate.net/publication/261881391_Epigeneti...
2. https://www.sciencedirect.com/science/article/pii/S193131282...
As a counterpoint I’ll say that to the extent that the transfer of antibodies prevents or reduces infant illness, that is a win in the dimensions you describe on its own. A sick infant is both wildly impractical and hard to bond with.
For example, in this interventional cohort study with breastfeeding promotion [1], ”the percent of children having pneumonia and gastroenteritis declined 32.2% and 14.6%, respectively, after the intervention.”
[1] https://www.nec.navajo-nsn.gov/Portals/0/NN%20Research/Biolo...
Does breastfeeding negatively impact father-child bond ? I find it highly unlikely. We do know for a fact that it’s better for health.
Exclusive breastfeeding (not exclusively feeding breastmilk, but exclusively breastfeeding) would to a certain extent, yes.
In early stages of life the mother’s presence will never not be essential.
And the science shows that the health benefits are minimal.
All the nurses, midwives, and doctors I know declare otherwise
That's the conclusion of a new study that looked at markers of physical and mental health across the generations."[1]
Of course, there could be many reasons for that.
[1]https://www.webmd.com/a-to-z-guides/news/20210325/gen-x-mill...
The whole process is as simple as dragging the baby over, taking one breast out and bringing them near to it. The baby will take care of the rest.
Mothers do get sleep, including during the day together with the baby. There are solutions out there for many frequent or rare problems. A good midwife and experienced mothers in the family / circle of friends are priceless.
Of course some women can’t breastfeed and they deserve support. But downplaying the benefits of breastfeeding because it may hurt the feelings of some mothers is not the way to go.
It’s disappointing but not surprising that you’re saying that mothers need to go to work in the US. AFAIK in many parts of Europe they take many months off (often 6-12) to spend time with the baby. For some of them, it’s the only time in their life that they’ll get the chance to do that. Work can wait.
Why do mothers need to work in the US in the first 6 months of their baby’s life? Why can’t one of the richest countries in the world pay them to stay at home?
As for parental leave: why not pay men to stay home? Why the presumption that women must be the ones to sacrifice their careers? Because "breastfeeding"? That's a pitiful justification.
I'll say this though - breastfeeding can be a complete mystery for new parents and doctors are often clueless about it. A competent midwife which is familiar with the typical issues is priceless. It's good that there's formula available for those cases where the woman can't breastfeed or the baby is having difficulties and the parent's don't know what to do and can't find competent help.
In the EU, the parents get a number of months which can be split between them. Fathers in Germany for example take a few months off. Because breastfeeding, because moms often want to spend time with their babies and yes, sadly often also because they earn more.
Having such a strong prior on preferring it has made many people's lives much harder than necessary.
My argument is merely that our opening position, until proven otherwise, should be that the child benefits. (It can, unfortunately, simultaneously be hard for the mother and beneficial for the child. Many aspects of parenting are.)
And again I do think it’s important to note that huge numbers of children grow up well on formula. So if breastfeeding doesn’t work out for whatever reason there’s no reason to lose sleep over it. We can suspect it is beneficial and yet make a rational choice to forego it based on other factors.
There is a good reason they tell you to put your own oxygen mask on before helping your child in the case of a depressurizing plane.
I think it just protects them while they are fed, does not offer long term protection.
Anecdotally ours started to get way more sick in daycare after we stopped breastfeeding, but it also coincided with autumn season.
>But from what I remember there is good evidence that it improves the baby’s immune system among many other things.
>So bottom line is in the absence of massive amounts of strong evidence against breastfeeding, by default you should favour it.
These are all bad arguments.
It does, it means that newborns don't have to be born developed enough to get their own food.
Even more so it's developing a formula milk industry; it's got to be a huge advantage.
Breastfeeding is important for attachment and mental health, see:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1459116/#:~:tex....
In the absence of health issues to the mother, breastfeeding is always preferable.
It was such a blessing. We got better sleep (tried it both ways), kid got fed more efficiently so wake time was shorter, nice bonding. Neither parent was so heavy a sleeper as to be a danger, no one was intoxicated either.
It’s important to never drink alcohol or go to bed impaired in any way.
Reduces `type 2 diabetes` risk. https://www.nmcd-journal.com/article/S0939-4753(13)00274-3/f...
It reduced the risk of reduced risk of breast cancer, ovarian cancer, and endometrial cancer. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4670483/
Do I need to mention maternal bond as well as weight loss? Instead of dieting or stuff like that, it's a more healthier option.
Just see the 1970s Nestle scandal. https://en.wikibooks.org/wiki/Professionalism/The_Nestl%C3%A...
See also sunscreen [1].
[1]: https://www.outsideonline.com/health/wellness/sunscreen-sun-...
One of the things that caused Robert Lustig [0] to go down the "fructose is a poison" rabbit-hole was he had parents with obese infants coming to him for help. What he found was the WIC-provided formula these mothers were giving these children was full of fructose making the infants obese. I think you'd struggle to produce a similar outcome via breastfeeding.
Bf is really hard for a lot of women, and other women (me) don’t enjoy it. It’s really painful in the beginning, means that I’m solely responsible for feedings and night wakeups, puts me at risk of mastitis, thrush and postpartum depression (probably exacerbated by lack of sleep), requires me to stay close to home for months. There’s nothing special about breastfeeding apart from this feeling people have that “natural” is better. You probably wouldn’t limit your own food intake to what’s “natural” - what you can kill or grow within walking distance of your home - why would you limit your baby’s in the same way?
I remember back in the early 2010's there was this 'hack' going around where you could manage to only sleep for 2 hours or something a day, but you had to grab sleep every 4 hours for 15 minutes to get the REM cycle in. I'm likely totally off on the schedule, but the gist was very little sleep.
Recently, a sibling became a parent and I was reminded of that 'hack' and told them. My sibling just laughed and said 'Oh, so nerds discovered motherhood huh?'.
As the children mature, the heritability of their IQ grows from roughly 0.45 to 0.8 (similar to height) [1]. The fact that the age of the child at the time of the IQ test is such a large factor is often not accounted for in research, which creates inconsistent results. Ideally, breastfeeding research would compare the IQ at adult age of children that were breastfed for different durations, normalized against their parents IQ.
https://en.wikipedia.org/wiki/Heritability_of_IQ#:~:text=Ear....
However, it’s important to realize that environment is generally fairly constrained in these studies. A Twin study is hardly comparing Sierra Leone with Japan, or the Netherlands with North Korea. Extremes like iodine deficiency, disease, or fetal alcohol syndrome are similarly excluded.
FWIW, you see the similar trend in adopted children - as they grow older, their IQ trends from being close to their adoptive parents to getting closer to their (completely uninvolved) biological parent.
except if you look at the other comparisons made (eg. "Unrelated children—Reared together—Adults "), the correlation factor can go quite a bit lower than 0.7-0.8 (eg. 0.04). The fact the correlation can go this low casts doubt on your theory that the environment is "constrained".
“Same person (tested twice) .95 Identical twins—Reared together .86 Fraternal twins—Reared together .55 Biological siblings—Reared together .47 Unrelated children—Reared together .30 Parent-child—Living together .42 Adoptive parent – child – Living together 0.19 Identical twins—Reared apart .76 Fraternal twins—Reared apart .35 Biological siblings—Reared apart .24”
So siblings reared apart had less correlation than unrelated children living together.
Like what “raised separate” means.
Was one raised in a Soviet gulag while the other was raised in an Israeli kibbutz?
That makes me think it's just a generic "I don't like this conclusion so I'll criticize it" Joker card that people play, and not a legitimate debunking.
Sure. To take this line of reasoning to its conclusion, an environment that has no oxygen or is otherwise uninhabitable, would prevent any human from living or having any mental abilities whatsoever. In this sense, environmental influences would completely dominate genetics. Similarly, changing 50% of a human's DNA would have them live life as a stalk of wheat.
What's your point?
Breastmilk contains the most microRNA of any body fluid[1] and has the potential to modulate gene expression, so there may be ways breastfeeding affects the genome that we don't understand yet. How long a child is breastfed is associated with epigenetic differences in children.[2]
Breastfeeding is negatively associated with the methylation of LEP. Childhood obesity is associated with lower cognitive performance.[3]
1. AAP talk on long term breastfeeding epigenetic effects: https://www.youtube.com/watch?v=-bUeSqPOCTc
My interpretation is that after removing the social bias which is usually prevalent in related studies and discussions, not much of an effect can be observed.
The older one had not enough breastfeeding and had much more minor illness over the years.
The younger one had all breastfeeding during the early time and only had 2 illness in the similar time period.
As for others, I cannot comment yet. Let's see.
Nobody wants to think they're a bad parent and the vast commercial interests here don't make this any easier.
I don't think we have enough data.
Or breastfeeding from a wet nurse vs breastfeeding from one's biological mother?
Sounds like we still know so little, but I'd be curious about these two questions as well.
https://www.who.int/health-topics/breastfeeding
Too clever by half springs to mind with this article.
Your sanity has a bigger influence on the well being of your child than any single factor like religiously breastfeeding.
Breastfeeding is incredibly convenient when the mom is not working, and cost efficient. But if it becomes impossibly inconvenient or costly, eg while mom is working, dont beat yourself up if you have to resort to formula to bridge the gaps.
Also, baby formula marketing would lead you to believe that formula with omega3 will make your babies smarter too. That's probably the lie you should disbelieve in.
Raising a confident well adjusted child is more important to me than high IQ, and there is no objective way to measure that.
If you can breastfeed your baby, do it. Give it a real go.
But if it is leading to a true loss of sanity, let it go.
I've raised 3 and breastfeeding was a part of each baby's start. There were reasons why none of them made to the promoted 1 year target. But I saw real benefits that I associate with breastfeeding in each child up to today.
Diet before, during and after pregnancy can affect the nutritional composition, and it can be low in vitamin D, iodine, iron, and vitamin K. Vitamin D and K are usually supplemented (K is given at birth).
Some women (around 30% iirc, can't find the number atm) do not have B. infantis because of low gut diversity, which is really important for infant gut health and long term immunity. Infants are usually exposed during vaginal birth, so babies born by c-section are at risk for not having B. infantis colonize their gut. Breastmilk can be a source of B. infantis.
Some communities with heavy environmental contamination have had lead levels as high as 41.1 ppb [1]. Baseline heavy metal content for most areas tends to be more in line with formula.
Maybe one way to think about it is this: walk into an elementary school and interact with kids in a classroom for any amount of time you want, access all their test scores. Then guess which kids were breastfed and which were not. I would bet that you wouldn’t do much better than chance.
If you spent a day with a class of kids you'd probably (unless asking them specific questions about it) not be able to guess any specifics of their parents' different parenting techniques, does that mean that parenting doesn't matter and kids should just be ignored when not being fed?
The effect of having loving parents completely dominates whether you breastfeed or bottle or formula.
1) Because large effects are more robust than tiny effects to things like researcher bias, choice of statistical methods, and experimental error.
2) because perturbing large effects are more likely to see real world difference for every day life than small effects. The conclusion from studies of breastfeeding versus bottle is it does not matter because it is a tiny and likely negligible effect (even if the effect is highly statistically significant).
This does not elicit faith that the author has any insight whatsoever.
Edit:
I’m not particularly motivated by talk of IQ in general because the groups that get fixated on it rarely have overlap with my own interest in human cognition. I’ve found this stuff to often be sensationalist navelgazing nothingness at best.
I find IQ topics go as you suggest, generally.
Parenting topics around IQ are a slightly different beast: middle-class American parents (at least) are obsessed with making their baby smarter than your baby. It has been a thing for 35+ years. Something about the competitiveness of the boomers in the mid-80s spiked a baby IQ frenzy that has only worsened.
I think the author is very smart at selling Substack Subscriptions to post-COVID moms.
In my experience it’s been the opposite. There’s stigma around breastfeeding in public. People aren’t breastfeeding and using formula because of a lack of education and the associated stigma.
I think these studies are a big part of it. There’s pressure from doctors and hospital staff to breastfeed when you have a new baby, and a key part of the sales pitch is increased IQ. It’s not hard to see how that causes serious guilt for moms who use formula.
Of course this is anecdata.
Ours UCSF, pressured and pressured my wife to breastfeed even though her milk was having massive problems coming in. Instead of allowing formula they only allowed donor breast milk supplementation by tubes that were taped to my wife's nipples, to attempt to prevent "nipple confusion".
The way it was explained to us, the idea is to continue to stimulate milk production while supplementing. We used it for a week until production was sufficient. I personally enjoyed this as it allowed me to be more involved and removed the stress of knowing if we were feeding our child enough while still getting what we could from breastfeeding.
We definitely had a great hospital. With all the stress and lack of sleep, I'm not sure I would've kept calm if they'd imposed stuff that way. Not letting you the choice of using formula when using the breastfeeding aid seems crazy.