How much a baby is touched leaves measurable effects on DNA methylation (2017) (opens in new tab)

> I did it not for the posted reasons, but just beacuse it felt right to me.

It probably felt right because it's natural. Newborns pretty much stayed with their mothers 24/7 for all of human history. This is true for chimps ( our closest ancestors ) and even our common ancestor. It's only recently with the push to get women into the workforce where women were encouraged to separate from their newborns so that they could go back to work.

> As soon as they came out, I held them and sang and hummed the same tune to them. It immediately calmed them - with my first, she immediately relaxed and stopped crying whil the nurse took her vitals, measurements and pricked her heel.

The mother's voice also helps premature babies develop. The fetus probably has gotten accustomed to the mother's voice in the womb and associates it with comfort and safety. Perhaps it's an evolutionary relic since many newborn animals are drawn to their mother's voice and vice versa.

https://www.psychologytoday.com/intl/blog/shouldstorm/201909...

Not sure how much it is related, but I learned how touch has a powerfully lasting impact when I read about babies from an underfunded Hungarian orphanage having lots of health problems later in life because of how little they were touched.

Reading, too. My wife and I read to our two boys when she was pregnant with them and they loved book time almost immediately, even though they slept through it for the first month or two.

Fast forward and we have one 4 and one 7 years old and they are obsessed with reading and would do it every waking hour if we'd let them.

Here's another magical experience. No one will believe it, but it's true, so here goes.

We too would read, sing and hum to my son in-womb. While doing so, we'd occasionally hear a loud click, the source of which we couldn't determine. But after he was born, we found out. He would press his tongue hard against the roof of his mouth then release it with a suction "pop". Was he trying to communicate back to us from the womb? We like to think so!

Our 8 week old will cry if she is not held 24/7. Whilst it is incredibly tiring and hard work, we've found a way to make it work.

You need to give that knowledge time to spread. The vast majority of living adults learned in school that the DNA is fixed and the surrounding stuff is just junk. Eventually everyone will know about epigenetics but how else would you spread the information if not with articles like these.

The article never claims that it's mystical...why do you say it's sensationalist?

How long are epigenetic changes supposed to last? Do changes caused by trauma last longer than slower changes?

I have some background to understand this (bioinformatics Honours), but am not an expert. What I can say is that the study at this point, if based on DNA methylation, does not even suggest that the effect is of physical contact is positive (to be Devil's advocate, the DNA methylation from physical contact could have a negative effect).

The study does ask for indicators (crying, behaviour, etc.) but with those parameters you can already try to correlate a lot of physical contact vs. less contact.

They are trying to tell whether methylation is worth studying (at all) in the context of more vs. less contact with your child. Personally, for the purposes of raising a child, I don't think these studies say anything at all. It's more important to stop panicking about nonexistent threats that social media wackos will try to convince you of.

Epigenetics is a very interesting field of study and is like a downtuned Lamarckian inheritance all over again. Things like chronic inflammation are still far from well understood. The body is like having 2 000 000 000 years of Wikipedia and all its edit history crammed into one string of DNA letters. And now we learn that apparently metadata (the DNA methylation) is also crammed into the whole thing and even that changes all the time.

By the way, for that matter, what constitutes "affectionate physical contact" quantitatively is not clear to me. I think each child's particular emotional need at any time is really difficult to pinpoint. I had a great childhood and parents, but I think that I always had a sort of angst (maybe competitive angst?) that really can't be said to be anyone's fault. These days if you feel funny and go the psychologist they will probably say: "Don't worry. It's just appropriate affect. If you spend 15 hours a day on Instagram then you are supposed to feel funny."

This is an example of the sort of cases in which I worry that experts become clouded by zealotry; I think it's more likely that a generalist-at-a-distance will poke the right holes in the methodology of these kinds of studies.

Being touched is an undeniable signal you are surrounded by the tribe, which triggers the reproductive sequence, since it takes a village to raise a child.

That would make a good sci-fi - an army of sociopaths that live until they’re 200 years old.

Can you back up your implication that the saliva epigenome has no other meaningful and impactful correlates?

> "consequences on the epigenome"

Indeed such a stupid phrase. Any dynamic activity in the body, every process or change which happens due to dynamic actions during life is technically a consequence on the epigenome, because it requires some cells/organs to change some chemical reactions, produce more of this stuff and less of that stuff - it requires activating some genes and deactivating other genes. You drink tea - it has consequences on the epigenome. You think happy thoughts instead of sad ones - it has consequences on the epigenome... You excercise - it has consequences on the epigenome...

>I think there is a high chance that is 100% bullshit.

I haven't read the paper this article is based on, so I can't comment on the study or the reliability of the results.

However, epigentic effects related to the degree of maternal touch have been convincingly demonstrated in naked mole rats in crossover studies. I posted about this research previously. (https://news.ycombinator.com/item?id=18749285)

One thing that we know from decades of twin studies is that childhood family environment explains a vanishingly small percent of long-run adult outcomes.

Contextualizing this single study's result against the much larger, more established evidence from twin studies strongly suggests that one or more of the following is true.

- The results are spurious and won't replicate.

- The results are true, but the association is not causal, and is simply proxying correlation with an upstream factor.

- Lack of touch does lead to methylation in the short-term, but by adulthood there's strong reversion to the mean.

- The methylation has no significant impact on any actual metric that we care about like success, health, personality or wellbeing.

I'm not a professional scientist, but shouldn't the spirit of science be curiosity and exploration at all times, not shooting down a new idea as soon as you hear it?

If such an attitude were present in every person, science would not progress at all.

I'm not that long a veteran here, but I think at HN we are more interested in having our minds and ears open and feeling we can comfortably share and discuss articles that make us think, than fostering an attitude like this.

I mean this with respect, whoever you are.

This article is terrible and did the grave disservice of not mentioning the work that has been done on this front using rats. Obviously, we cannot ethically reproduce the RCTs in humans to establish cause and effect, but there's sufficient evidence to form hypotheses and spur investigation in humans. I'm having trouble finding the exact primary literature that I wanted to cite just now, but here are a couple of things worth looking over:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682215/

https://en.wikipedia.org/wiki/Michael_Meaney

scientific study: "The importance of touch in development", Brain Research Centre and Department of Psychology, University of British Columbia, Vancouver. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2865952/#__ffn_... (as commented elsewhere)

I think they forgot to say being more touched probably means parents are more close by, more caring. Why would you not touch a baby if you are constantly close by? So probably not BS, just a study say is right, but not for all the right reasons.

To add to that, there are so many problems with self-reported studies.

> They also asked parents to keep track of how long and how often they gave care to their child that involved physical contact, according to a press release.

The article is talking about methylation, which I always interpret to mean they're referring to the epigenome. It doesn't change our DNA, so much as the expression of it.

There's a special thing called "Epigenetics". The genes coded in DNA don't change. But how they're used can change.

There's methyl groups that attach to the DNA. These stop parts of the DNA being read.

There's Histones which wind up your DNA and control how much can be read.

These are used control which parts of DNA are used by which cells. Evey cell has the same Genome, but each cell needs a different program to function, so changing the Gene Expression you get a different kind of cell.

These are not mutations. They're more like tags.

Ditto :D