
Breastfeeding 'linked to higher IQ' - datashovel
http://www.bbc.com/news/health-31925449
======
paulfr
Just 2 weeks ago, I won a machine learning contest with a $20,000 prize pool
where the goal was to predict the IQ of a child at age 7, based on various
biological measurements and demographic indicators. The data includes whether
a child was breastfed.

After reading the article I did some very quick computations and my finding
based on the model I developed is that children who were not breastfed have an
IQ impairment in the 1-3 IQ points range, after accounting for confounding
factors.

This is very consistent with the results published here.

Compared to this study, I believe the methodology I'm using is more powerful
for three reasons:

\- much larger sample size: the dataset I have access to comprises 12015
children, compared to 3493 for the study

\- a larger set of confounding factors is accounted for: notably, the data
includes height and weight measurements at up to five points in time

\- confounding factors are fully accounted for, rather than hand-waved away.
This is a complex model based on random forests and linear model, and the
results are entirely cross-validated.

Stay tuned for more detailed computations. I will also ask the organizers for
the exact definition of breastfeeding used.

\---

Edit:

On the other hand, the study is still very appealing because according to the
authors, there is little correlation between demographics and breastfeeding in
Brazil, whereas the validity of the effect I'm reporting is dependent on
whether the demographic model is powerful enough to remove the correlation.
Still, I believe most of the correlation is easy to remove, and it isn't clear
that there aren't subtle demographic effects even in Brazil. In particular,
the proportion of participants with missing IQ data seems to decrease with
duration of breastfeeding, and I don't know if they have an explanation for
that.

~~~
mkagenius
> impairment in the 1-3 IQ points range, after accounting for confounding
> factors.

But 1-3 IQ points doesn't seem much, right? I mean, what difference would it
make in real life activities?

~~~
streptomycin
It's roughly the same as the change that happened when we stopped using leaded
gas, which seems to have had a huge affect on society.
[http://en.wikipedia.org/wiki/Tetraethyllead#Toxicity](http://en.wikipedia.org/wiki/Tetraethyllead#Toxicity)

Also it's just one relatively simple thing. Imagine we find several things
that can all increase IQ by a couple points...

~~~
cheatsheet
I've never gotten my IQ tested, but when I read about studies like these -
they usually demoralize me from fear of competitive behavior. I think this
leads to low self esteem, and the imagining that I have a low IQ (high marks
through schooling and post graduate education, MSc, possible imposter
syndrome) as my default attitude. It can be a self defeating attitude, but
what it usually does is make me argue with people about IQ tests, and explain
why they are not necessarily indicative of intelligence, individually or
globally.

I can imagine that merely the act of measuring IQ has significant effect on
the population. I can not imagine a population that exists without it, but I
imagine it would also have a huge effect on society, as you similarly
hypothesize about the 1-3 point increase across the population globally.

------
jtheory
I'm honestly totally in favor of breast-feeding, when it's a reasonable
option. I don't want anyone to _avoid_ breast-feeding because they think (as
was believed for quite a while, actually) that formula is better.

But this line from the OP slightly freaked me out -- just for acknowledging
the possibility:

> But they say mothers should still have a choice about whether or not to do
> it.

Have they _forgotten_ the abortion debate? There are some relevant points in
there, even if formula-feeding actually cost 50 IQ points, reliably.

But it's more than just that.

Parenting is demanding and unavoidably full of compromises, for just about all
parents. Most people just think in overly-simplified terms of what's "right"
and "wrong" in parenting decisions, which means that the mother who can't
breastfeed because she's got mastitis gets to suffer _both_ from the pain and
from guilt of imagining her child's IQ points decreasing; nice.

But really -- feeling guilty whenever you see your child is probably quite a
bit _worse_ than any harm not breast-feeding them may or may not cause.

I feel like there should be just a list of priorities, for parents to review
when they're choosing their individual compromises, and at the top of the list
would be "dedicate time when you're feeling _well_ to your child". Then you
can spend that time actually being supportive, kind, fair, consistent, and all
of those things that go out the window when you're feeling awful.

And you may be feeling awful if you're compromised away too much of your
sleep, if you're in pain, if you've faked being happy for too long, because of
some article you read about something that was "right" or "wrong" for your
child.

All of these other things -- like breast-feeding -- should come below that.

Kids don't want/need more time, full-stop; they want/need more time with
parents who are actually doing okay.

~~~
jwdunne
In some cases, the pressure to breastfeed can do more harm than good. If the
parent is feeling stressed, as it can be an extremely intense and also painful
experience, the bonding process can suffer. More importantly, some mothers
just cannot produce enough milk. The father of my adopted son forced my wife
to breastfeed. Over a 3 month period, the poor boy lost a dangerous amount of
weight and needed a stay in hospital, where he had strict, formula-based
feeding schedule. If my wife was asleep, the nurses wouldn't even bother
waking her up, they'd just feed him.

The result, and not to say this is a cause but a potential contributing
factor, is that this unfortunate boy has major developmental delays, is unable
to speak properly and what he can say he often doesn't understand. I
personally have had my past investigated by social services to ensure I won't
have a negative impact on his development (I suffered from psychosis in my
teenage years, likely due to stress from attention deficit disorder and a
traumatic event). Teachers and myself have noticed, for example, he regularly
speaks well out of context, which is notably worse than his peers. There's a
tough road ahead.

With articles like this, we are looking at individual, specific factors when
the reality is much more complicated and results from an interplay of
thousands of microscopic to large and obvious factors. With children and their
development, it is just not simple. We are, whether we like it or not, complex
systems.

Parents of healthy body and mind want the best for their children. The
pressure of this alone is fantastically great. The results of additional,
external, pressure could do more harm than good.

~~~
deepGem
"More importantly, some mothers just cannot produce enough milk" \- Is there
any anecdotal evidence to prove this. One lactation consultant told us that
this claim is totally false. According to her, all women who give birth can
and will produce enough breast milk and she had the evidence to prove that.

~~~
UnoriginalGuy
She sounds like a real peach.

Honestly that opinion seems more colored by her political views (i.e. breast
feeding good, formula evil) than any scientific or medical evidence.

I've met lactation consultants just like that, and they often go into
diatribes about how hospitals/doctors are evil and push formula on new mothers
(which wasn't true at all, in fact the hospital we used had a nurse
specifically to help mothers breastfeed and offered heavily subsidised
classes).

While getting started with breastfeeding is hard and mothers should be
encouraged to keep at it. Some mothers simply never produce, even after trying
that hard, or that long. At a point you're putting your child's life in danger
if you keep trying without results (and, no, I do not mean after just a few
hours -- that's normal, I mean days).

Honestly I'm pro breastfeeding but I find a lot of other pro breastfeeding
people insufferable. No, sorry, but people are in fact good mothers or fathers
if they use formula. No, sorry, they aren't automatically ignorant if they use
formula. No, sorry, you or your child aren't superior because you breastfeed.
No, sorry, it really isn't appropriate to approach random people in the street
and lecture them on why they're raising their child wrong.

~~~
patja
Is "breastfeeding good, formula evil" really a political view?

It is not hard to find cases of formula being promoted over breastfeeding to
the detriment of infant health and development. Case in point:
[http://en.wikipedia.org/wiki/Nestl%C3%A9_boycott](http://en.wikipedia.org/wiki/Nestl%C3%A9_boycott)

------
rayiner
The 1-3 point IQ advantage is widely and consistently reported in the
literature, and it's probably right as far as it goes. However, studies that
additionally adjust for socioenvironmental factors (mothers who breastfeed are
more likely to read to kids, have larger vocabularies, etc), show results
around 1 IQ point:
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633786](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633786).

The "mothers should have the option" bit in the article was really off-
putting. As if taking the option away was even on the table! It bears keeping
in mind that the vast majority of the current adult generation was formula-
fed. In 1971, only 25% of kids were breastfed in the hospital, and only 8%
were still breastfeeding at 3 months.

As a metacomment, recommendations having to do with parenting are myopic. They
lack any semblance of cost-benefit analysis, and the attitudes in the medical
community about how women should mother date back to a time when womens'
opportunity costs for labor-intensive parenting choices were nothing.

Also often ignored is how these choices affect fathers. Breastfeeding removes
the father's ability to independently take care of an infant. Because feeding
is a bonding experience, this creates a dynamic where the child looks at the
mother as the last line in being comforted. This is a choice couples can make,
but it is one that involves trade offs, which the medical community ignores.
It would be one thing if they just left it to patients, neutrally presenting
the data and letting parents evaluate the trade-offs. But they tend to hide
the data and aggressively push their interpretation of the proper trade-offs.

~~~
grandalf
> Breastfeeding removes the father's ability to independently take care of an
> infant. Because feeding is a bonding experience, this creates a dynamic
> where the child looks at the mother as the last line in being comforted.
> This is a choice couples can make, but it is one that involves trade offs,
> which the medical community ignores.

What about a breast pump? As long as some lactating female provides milk, the
milk can be frozen for months and is nearly as convenient as formula for a
father.

Also FWIW men can lactate if appropriate hormone injections are given.

~~~
dpark
> _What about a breast pump? As long as some lactating female provides milk,
> the milk can be frozen for months and is nearly as convenient as formula for
> a father._

There have been few (if any?) studies that look closely at breastfeeding vs
bottlefeeding pumped milk. Our society has jumped on the "pump and bottle"
wagon because it's seen as a viable way to allow women to go back to work
sooner while still "breastfeeding", but it's not known if this actually has
the same effect.

Does the increase in IQ/whatever come from the nutritional content of the
breastmilk? Does it come from antibodies or other contents that might be
impacted by refrigeration/freezing followed by reheating? Does it come purely
from the emotional bonding that breastfeeding promotes? We don't know, because
we don't even know why breastfeeding is better than formula, and we're
basically giving medical advice blindly when it comes to pumping.

But for what it's worth, the difference is so small as to be pretty
meaningless. The "gap" is going to be dwarfed by other factors, both genetic
and environmental.

~~~
grandalf
True, but I think there has been research into the immunity benefits of breast
feeding at least for the first few months...

------
sjwright
While the article does acknowledge that the study only shows correlation and
not causation, it doesn't suggest what seems to me the most intuitively
obvious alternative hypothesis.

We know that increased rates of mental stimuli and social interaction are
beneficial to a growing brain. Perhaps breastfeeding correlates with parents
that have more free time to interact with their child.

~~~
learc83
Researchers have considered your hypothesis. There have been many attempts to
eliminate confounding variables in these studies (this doesn't mean that they
were necessarily successful in doing so, but they did think about it). Often
they attempt to control for differences in parenting styles, which should
cover how much time they spend interacting with their child.

Also until 6-10 months, babies can't hold their own bottles, so someone is
probably still interacting with them (unless you prop up the bottle and leave
the baby alone, which is possible but not recommended).

~~~
sjwright
Bottles can be held by disinterested third parties.

Boobs rarely can.

------
pgsandstrom
The estimates were not adjusted for parental IQ:
[https://pbs.twimg.com/media/CAXhyklUkAEZ-
PD.jpg](https://pbs.twimg.com/media/CAXhyklUkAEZ-PD.jpg)

Also, the correlation was just 0.42:
[https://pbs.twimg.com/media/CAXofbqUgAE33iR.png:large](https://pbs.twimg.com/media/CAXofbqUgAE33iR.png:large)

------
BenDaglish
It interests me that the conclusion of these studies is almost always
presented as breastfeeding increasing IQ (or conveying health benefits or
whatever). Surely, breastfeeding is the _norm_ , and this headline should be
"Bottle feeding linked to lower IQ"?

~~~
DanBC
Reframing it like that makes it seem like parents who formula-feed (because
you can pump breast milk into a bottle) are harming their children.

There's already enough pressure on women to breast feed and I'm not sure it's
useful to put more on. It'd be better to make sure women can get rapid access
to breast feeding consultants.

~~~
BenDaglish
>makes it seem like parents who formula-feed are harming their children

Well, if the studies are to be believed, then that's exactly what _is_
happening. I completely understand the "pressure on mothers" argument, but I'm
not sure that really flies, especially given the (albeit more subtle these
days due to legislation) opposite pressure put on mothers by Nestlé and the
rest.

I also find the fact that initial breastfeeding rates vary so wildly by
country (from 98% in Sweden though to 57% in the US) interesting, and again
more likely to do with commercial and social pressures of the same kind than
to do with physical differences between mothers worldwide. While-ever the
argument is presented as "Breast is Best" rather than "Artificial is Worst", I
suspect this will continue.

~~~
DanBC
I suspect that socially progressive Sweden makes it easy to breastfeed while
repressive US (Facebook bizarely banned photographs of breastfeeding mothers)
doesn't.

------
datashovel
I definitely take studies like this with a grain of salt, though I do find
them interesting. This one does appear to be from a sufficiently large sample
size.

Besides this, though, I find it interesting that humans feel they can
sufficiently reverse engineer breast milk to replicate the health benefits.
Not saying at all that eventually this won't be possible or probable.

But the "original formula" has gone through at least tens of millions if not
hundreds of millions of years of evolution. From this respect I'm in complete
awe that we have this nature-given tool, and astonished that more humans don't
do this for their children.

~~~
aikah
> I definitely take studies like this with a grain of salt

as everybody should, the problem is the media publishing these stories know
that the only thing people read are the headlines.

> Experts say the results, while not conclusive ...

The article says one thing and its opposite. The goal here isn't to inform but
to distract. Absolutely no conclusion can be made out of reading this article.

~~~
colordrops
What exactly is wrong with this study?

~~~
aikah
Because you read the study ? there isn't even a link to the study in the
article. The article is garbage.

------
cssmoo
Maybe but it certainly _is_ linked to epic levels of smugness and superiority
complexes on the part of the parents and healthcare system. At least here in
the UK.

My oldest is quite intelligent. We've had "I bet she was breast fed" more
times than I can count. The reply is "no, it's a combination of genetics and
nurture"...

~~~
learc83
Even the most generous estimates are that breastfeeding adds a few IQ points.
Definitely not noticeable for an individual.

However, at the population level, which is what the healthcare system is
dealing with, that's a huge deal. Imagine if the average IQ of the entire
population were shifted up by several points.

~~~
dagw
_Imagine if the average IQ of the entire population were shifted up by several
points._

I guess it depends on the starting point. I imagine that shifting the average
from 85->90 would have a much bigger effect than shifting from 105->110\. Most
studies seem to show a pretty sharp diminishing returns when correlating IQ
points to just about any measure of 'success'.

------
datashovel
I should've done this last night, now that I see that this ended up on front
page for a while.

[http://www.thelancet.com/journals/langlo/article/PIIS2214-10...](http://www.thelancet.com/journals/langlo/article/PIIS2214-109X\(15\)70002-1/fulltext)

[http://www.thelancet.com/pb/assets/raw/Lancet/stories/audio/...](http://www.thelancet.com/pb/assets/raw/Lancet/stories/audio/langlo/2015/langlo_150317.mp3)

------
Symmetry
This is something people have been going back and forth about for decades.
There's even been a study that used more people and was randomized and
controlled. You can read actual literature surveys of all the ways parents can
affect their kids' IQs here:
[http://squid314.livejournal.com/346391.html](http://squid314.livejournal.com/346391.html)

------
nilsjuenemann
It's already known since a while that breastfeeding is a reason for a higher
IQ. There was a study in 2007 that the correlation between breastfeeding and
the IQ is moderated by genetic variant in FADS2.

[http://www.ncbi.nlm.nih.gov/pubmed/17984066](http://www.ncbi.nlm.nih.gov/pubmed/17984066)

------
amelius
There is also a negative link between breastfeeding and ADHD, [1].

[1] [http://www.medicaldaily.com/breastfeeding-new-ritalin-
resear...](http://www.medicaldaily.com/breastfeeding-new-ritalin-researchers-
investigate-its-effects-adhd-245873)

------
robmcm
How long before breast milk becomes so valuable women start selling it for
huge profit?

I'm going to set up Boober, an app for breast milk delivery and make millions!

~~~
dagw
It's already happening. You're late to this party.

~~~
robmcm
... as with every idea I have.

------
NateDad
Wrong title... Should say "giving formula reduces IQ"

