Chapter 6: Dwarfism and the Importance of Mothers

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Hey there, deep divers.

Have you ever paused to think about how incredible,

how utterly tangible the process of growth is?

One minute you're tiny, the next you're an adult.

But have you ever considered the complex hidden forces that sculpt us?

Things beyond just food, you know?

It seems simple on the surface, doesn't it?

Just eat and grow.

Right.

But the truth is, those intervening steps, the molecular ballet that turns, I don't know, spaghetti into a longer bone, it's actually quite profound.

And what's really fascinating here, I think, is how incredibly vulnerable this whole process is to something pretty unexpected, stress.

Exactly.

That's what we're digging into today.

We're taking a deep dive into a remarkable chapter from Robert M.

Sapolsky's Why Zebras Don't Get Ulcers,

the one called Dwarfism and the Importance of Mothers.

Yes, a powerful chapter.

Our mission, to unpack how stress profoundly impacts growth and development.

We're going to find some surprising facts, some connections.

We'll look at the basic biology, then dive into, well, the shocking idea of stress dwarfism.

We'll look at examples, historical and modern, uncover the biological mechanisms, and even explore the surprising role of touch or, you know, what some might even call love.

This deep dive will really show you how deeply intertwined our emotional and physical realities are, just how much more there is to learn about what makes us, well, us.

OK, let's unpack this.

Growth.

When we talk about growing, it's not just getting taller, is it?

Not at all.

The brain gets bigger, cells divide,

baby fat melts away, muscle forms, voices deepen.

It's like this huge civic expansion project for the body.

That's a great analogy.

And it's hard to believe, like you said, that your femur is made up of tiny pieces of, I don't know, chicken pot pie you ate years ago.

And growth is incredibly expensive, biologically speaking.

It demands this massive constant influx of nutrients, glucose, fatty acids, amino acids, all the building blocks.

And various hormones, they act like the project managers for this whole expansion.

So who's in charge?

Well,

growth hormone, GH, that's the big one.

It dominates.

Sometimes it works directly, breaking down fat cells to divert nutrients, those fatty acids to growing tissue.

OK, direct action.

Right.

Other times, GH first triggers something called somatomedins.

They're a class of hormones that actually promote the cell division, the tissue growth.

Ah, so GH isn't always doing the heavy lifting itself.

It delegates sometimes.

It's more like an orchestra conductor, and it's not a solo act.

Thyroid hormone plays a role, too, promoting GH release and kind of boosting the effects of those somatomedins.

Insulin does something similar, helps potentiate the growth signals.

Then around puberty, things get even more interesting.

The reproductive hormones jump into the mix.

Ah, right.

Puberty, a whole new set of instructions.

Definitely new players on the field.

Estrogen, for instance, promotes bone growth and increases GH secretion, especially in girls.

OK.

And testosterone.

It does similar things for long bones, but it really enhances muscle growth.

That's a big reason why boys tend to get taller and more muscular during puberty.

But here's where it got really interesting for me.

Testosterone, while it promotes growth, can paradoxically speed up the fusion of growth plates, those bits at the ends of long bones.

That's right, yeah.

It's a balancing act.

So if pubescent boys get really high concentrations of testosterone, they might actually end up a bit shorter as adult.

It can happen, yes.

Too much too soon, effectively.

And the flip side.

Boys castrated before puberty often grew quite tall, lanky, long limbs, like the historical castrati.

That morphology, yes, it demonstrates that principle.

A growth -promoting hormone in excess can actually limit final height.

It just shows how delicate the balance is.

It really does.

And that balance, it gets completely thrown off when the body faces severe chronic stress, because growing isn't exactly top priority when you're just trying to survive, is it?

It most certainly isn't.

Your body shifts priorities drastically.

And this leads us to this really shocking phenomenon called stress dwarfism, sometimes called psychosocial or psychogenic dwarfism.

Imagine, say, an eight -year -old child brought to a doctor because she's just stopped growing.

She's getting enough food.

There's no obvious disease, no parasites.

And the doctors can't find anything wrong physically.

Exactly.

No organic cause.

And then it often turns out there's something dreadfully stressful in her life, severe emotional neglect, maybe, or psychological abuse.

And just to be clear here, we're not talking about, you know, the normal stresses of childhood, like moving house or even parents having a tough divorce.

No, no, absolutely not.

Stress dwarfism is extremely rare.

It's seen in cases of just vast, grotesque family psychopathology.

Wow.

These are children who've been maybe incessantly harassed, psychologically terrorized, sometimes even locked in dark closets for months, food slipped under the door.

That's horrifying.

It is.

They present as stunted, years behind in growth, often in mental development too, frequently bruised, flinching postures, haunted expressions.

You get the picture.

Yeah.

But the core insight here is the body making a desperate sort of adaptive choice, suspend growth, conserve resources, deal with the threat.

Is there any recovery possible?

What's fascinating and somewhat hopeful is that if the stressor is removed before the child hits late puberty,

you know, when those growth plates fuse, some degree of catch -up growth is possible.

Wow.

Though often, some shortness and maybe some personality or intellectual stunting can persist.

It leaves a mark.

History even gives us a pretty chilling example, doesn't it?

King Frederick II of Sicily, back in the 13th century.

Ah, the natural language experiment.

Yes.

He wanted to find out what language humans would naturally speak if never spoken to.

So he had infants raised in isolation.

They were fed, clothed, but never held, never spoken to, no interaction.

And the result?

None of them survived.

None.

None.

The lesson, which is crystal clear to us now, is that optimal growth isn't just about calories and warmth.

It requires, as the chronicler put it, clappings of hands and gestures and gladness of countenance and blandishments.

Basically, connection, affection.

Precisely.

These infants, though well fed, they likely died of stressed dwarfism, a stark reminder from centuries ago.

And there's a more subtle, but just as powerful example from post -World War II Germany, right?

The two orphanages study.

Yes, a very telling study.

Both government -run, similar diets, similar medical care.

The key difference was the head caregivers.

The women in charge.

Exactly.

In one, you had Frawling Grun.

Warm, nurturing, played with the kids, sang, laughed.

The other had Frawling Schwartz.

Minimized contact, critical, berated the children.

And the difference in growth?

Predictable, sadly.

Schwartz's kids grew slower.

But then there was this unplanned twist.

Right.

Grin moved on and Schwartz got transferred to Grinsold Orphanage.

Correct.

And what happened?

Growth rates in Schwartz's former orphanage actually increased after she left.

Wow.

While the rates in her new orphanage, Grinsold Place, decreased, it's such a clear demonstration of how a single caregiver's emotional approach could literally impact physical development.

Incredible.

And there was a detail about favorites, too.

Ah, yes.

An important elaboration.

Schwartz wasn't maybe completely heartless.

She apparently had favorites.

These kids got more attention.

And they grew much faster than the other children under her care.

That just highlights the point even more.

It really does.

And it's worth remembering, this wasn't just a post -war German phenomenon.

Back in 1915, even with adequate food, many U .S.

orphanages had mortality rates near 100%.

Almost unbelievable today.

Even later, a third of infants were still dying.

This was when leading experts like Dr.

Luther Holt were actually warning against picking up crying children, calling it a vicious practice.

Tragic irony, isn't it?

The lesser orphanages where staff maybe weren't so up date on that advice probably just followed their instincts.

They often had lower mortality rates.

Because they were actually holding the babies.

It's heartbreaking.

These weren't just statistics.

They were lives lost because of a fundamental misunderstanding of human needs.

Profound misunderstanding.

And then Peter Pan.

There's a poignant real -life story behind that beloved classic.

Yes, J .M.

Berry's story.

It involves a British Victorian family.

The mother's favorite son, David, died young in a accident.

And the mother just shut down.

Completely grief -stricken.

Retreated to her bed for years, totally ignoring her younger son, who was about six at the time.

She'd occasionally mistake him for David, saying she wished her dead son had just stayed a boy forever, never grown up.

Oh, wow.

And this younger boy, deprived of his mother's affection, father was stern and distant.

He seemed to internalize this wish.

Despite being in an affluent family, no disease, no nutrition, he just stopped growing.

He physically stopped growing.

He did.

As an adult, he was barely five feet tall.

His marriage remained unconsummated.

And that forlorn boy was J .M.

Berry.

The author of Peter Pan.

The author of Peter Pan, whose work is just filled with themes of children who don't grow up or who die young.

That's truly heartbreaking.

It gives Peter Pan such a chilling dimension.

Like the psychological trauma just manifested physically.

It seems that way, yes.

So when a child experiences that kind of profound emotional neglect, what's actually going on inside their body to halt growth?

What are the mechanisms?

Right.

The biological nuts and bolts.

Well, the most consistent finding in children with stress dwarfism is extremely low levels of growth hormone, GH, in their blood.

OK.

Low GH.

Where does GH come from again?

It's secreted by the pituitary gland.

And the pituitary is regulated by the hypothalamus up in the brain.

Right.

The hypothalamus releases two key hormones.

Growth hormone releasing hormone, GHRH, to stimulate GH.

The on switch.

Exactly.

And growth hormone inhibiting hormone, GHIH, also called somatostatin, to inhibit GH.

The off switch.

Right.

In stress dwarfism, it seems the main problem is an overabundance of GHIH, the inhibitor.

It's actively driving down GH levels.

So the off switch is stuck on.

Pretty much.

Or the pituitary might also become overly sensitive to GHIH or maybe less sensitive to GHRH.

Either way, GH production plummets.

So it's a double whammy.

Less go signal, more stop signal.

It's like a deliberate physiological shutdown.

Precisely.

And it doesn't stop there.

Beyond just the secretion issues, there's evidence that the target cells themselves, ones that are supposed to respond to GH and somatomedins, become insensitive.

They just don't listen anymore.

Kind of.

Studies on infant rats, for example.

Yeah.

If you deprive them of their mothers, both their GH levels and the activity of a key enzyme for cell division, it's called ornithine decarboxylase or ODC helo.

They both just plummet.

Okay.

And here's the kicker.

If you then inject those stressed rats with GH, it doesn't restore the ODC activity.

The cells just don't respond.

Wow.

So the stress isn't just turning down the hormone.

It's like making the body deaf to it too.

That's a great way to put it.

It creates this systemic multi -layered resistance to growth itself.

Are other hormones involved in this shutdown?

Absolutely.

The sympathetic nervous system, our fight or flight system, seems to be overactive in these kids.

Makes sense, given the stress.

Right.

And its signals, like norepinephrine, can directly inhibit the pituitary from releasing GH.

There's even some evidence that blocking one branch of the system can actually normalize GH levels in a child with stress dwarfism.

Interesting.

What about the classic stress hormones like cortisol?

Glucocorticoids, yeah.

They likely play a role too.

Now their levels are often normal or even low in classic stress dwarfism, but some studies, especially in those infant rats separated from their mothers, show elevated levels.

And glucocorticoids are bad for growth.

Definitely.

They disrupt growth in multiple ways.

They block GH secretion.

They reduce how sensitive target cells are to GH and they directly inhibit the making of new proteins in DNA and dividing cells.

So they hit growth from multiple angles.

They really do.

Even levels just two or three times higher than normal can dramatically halt growth in children.

And it affects more than just hormones, right?

You mentioned digestion earlier.

Indeed.

Kids with stress dwarfism often have significant gastrointestinal problems.

That overactive sympathetic nervous system we mentioned, it can halt the release of digestive enzymes, stop the normal contractions of the stomach and intestines and block nutrient absorption.

So even if they are eating, their bodies just can't use the food properly.

Exactly.

They aren't efficiently extracting the nutrients needed for growth.

It's worth noting classic stress dwarfism, usually seen from age three onwards, seems mostly about the GH shortage.

But infant failure to thrive syndrome often involves these more pronounced GI issues as well.

This brings me back to that incredible hospital study you mentioned.

Yeah.

The one with the nurse.

Yes, that one's just remarkable.

It showed so clearly how sensitive growth is to the emotional environment.

Remind us what happened.

Okay, so a child with stress dwarfism was admitted to the hospital.

He was assigned a special nurse and he became really attached to her.

When he arrived, his GH levels were extremely low and his growth rate was basically flatlined, very low.

A few months later, still in the hospital under her care, his GH levels had more than doubled and his growth rate shot way up.

Why?

Without any hormone treatments?

Without any synthetic hormones and get this, he was actually eating slightly less food than when he first arrived.

So it absolutely wasn't just about nutrition.

Absolutely not.

It proved that point definitively.

But then his favorite nurse went on a three -week vacation.

And his GH levels and growth rate, they plummeted right back down to where they were when he was admitted.

Just from her being gone.

Just from her absence.

And when she came back, both GH and growth rate immediately rebounded.

That's just a stark illustration, isn't it?

How powerfully the body's growth machinery responds to that feeling of connection, of safety.

It really is utterly dramatic.

So if it's not just food or warmth,

What is that critical missing piece for a child in isolation or that rat pup separated from its mom?

How did they figure that out?

Yeah, researchers like Kuhn, Schanberg, and Hoffer dug into this with infant rats.

They systematically tested different factors, smell, milk, warmth.

And they found it really came down to touch.

But not just any touch.

Specifically, the right kind of touch.

What do you mean, the right kind?

OK, so you separate a baby rat from its mom, GH plummets, growth stops, standard finding.

Right.

Then you let it have contact with an anesthetized mother, just the warmth and passive contact.

GH stays low.

OK, so passive contact isn't enough.

Exactly.

But if you mimic the active licking behavior of the mother rat by stroking the pup with a small brush in the proper pattern,

GH levels normalize, growth resumes.

Just from mimicking the licking.

Just from that specific active tactile stimulation.

Other studies also showed that simply handling neonatal rats, just picking them up and touching them regularly makes them grow faster and larger.

So the insight is, it's a specific kind of nurturing touch that signals safety and well -being.

Precisely that.

Active nurturing touch.

Which brings up the huge question.

Does this apply to us, to humans?

It absolutely seems to.

There was an incredibly important study by Tiffany Field and her colleagues.

Directly inspired by this rat work, they looked at premature infants in neonatal wards.

These babies, you know, they get top -tier medical care, incubators, monitors.

But because they're so fragile, they were hardly ever touched.

Right, it was thought best to minimize handling.

Exactly.

So Field's team introduced a really simple intervention.

Just daily gentle touching and massage for some of the infants.

And what happened?

The results were just astonishing.

The touched infants grew nearly 50 % faster than the standard care group.

50%.

50 % faster.

They were also more active, more alert, they matured behaviorally faster, and they were released from the hospital almost a week earlier, on average.

That's huge.

A week earlier saves costs, reduces risks.

Enormous implications.

And months later, these touched infants were still doing better developmentally.

Wow.

What stands out to you about how something so simple, so low -tech, could have such a massive impact?

It really frames the absence of touch as a major developmental stressor, doesn't it?

It absolutely does.

It highlights how fundamental physical connection is.

And, you know, if you step back and look at all this research,

this word keeps kind of lurking between the lines, even though it sounds unscientific.

Which word?

Love.

Something, you know, roughly akin to love seems genuinely necessary for proper biological development.

And it's absence.

That's one of the most aching, distorting stressors we can possibly suffer.

It signals danger at a primal level.

Which sort of brings us to Harry Harlow's monkey experiments.

Famous, but also quite controversial.

Very controversial, yes.

This was back in the 50s to 70s.

Psychology then was really dominated by behaviorism.

Everything's about reward and punishment.

Pretty much.

Positive or negative reinforcement.

So the prevailing theory was babies love their mothers because mothers provide food, relieving hunger.

Simple stimulus response.

Seems logical.

Maybe a bit cold.

Harlow decided to test this obvious idea.

He raised infant rhesus monkeys with two types of artificial surrogate mothers.

One was just wire mesh, but it had a milk bottle attached.

Provided nutrition.

The food source.

Right.

The other was also made of wire, but it was wrapped in soft terry cloth.

Comforting, but no food.

Okay, food versus comfort.

So the behaviorists would predict the monkeys would bond with the wire mother, the food source.

But that's not what happened.

Not at all.

The baby monkeys overwhelmingly preferred the soft terry cloth mother.

They clung to it for hours, especially when scared.

They only went to the wire mother quickly for milk when they absolutely had to, then rushed back to the cloth mother.

Contact comfort won out over food.

Completely.

Harlow's famous conclusion was man cannot live by milk alone.

Love is an emotion that does not need to be bottle or spoon fed.

Powerful stuff, even if the methods were harsh.

What's the lasting insight from Harlow, despite the ethics?

Well, while his methods are rightly criticized today, his work was crucial.

It provided animal models for studying childhood trauma.

It helped us understand how early abuse or neglect can predispose individuals to become abusive parents themselves or to suffer from depression later in life.

So it opened doors for understanding long -term effects.

Well, it's kind of sad and pathetic, as Sapolsky notes, that we need experiments on infant animals to learn about the importance of love,

but maybe even sadder that we still seem to need constant reminders of its importance.

The sobering thought.

Okay, shifting gears slightly.

I'm personally not growing much taller these days, maybe wider, but growth hormone is still secreted in adults.

What's it doing if we're not getting taller?

That's a great question.

In adults, the growth hormones shift focus.

They're less about building the initial structure, the edifice, and more about rebuilding and remodeling.

Maintenance work.

Exactly.

Like the paint job, plastering the cracks.

A lot of this happens in our bones.

Bones aren't static.

They're dynamic, active tissues.

Constantly breaking down and rebuilding.

Constantly.

There's a process called resorption, breaking down old bone, and then formation, building new bone.

Growth hormone, somatomedins, another hormone called parathyroid hormone, which manages calcium and vitamin D.

They all supervise this constant turnover.

And bones are also calcium banks, right?

Our body's federal reserve for calcium, yeah.

Constantly exchanging it with other organs as needed.

So how do stress hormones mess with this delicate balance in adult bones?

Predictably, not well.

Glucocorticoids, especially wreak havoc.

How so?

They inhibit the growth of new bone by disrupting the precursor cells.

They reduce the body's calcium supply by blocking uptake from diet and increasing excretion through the kidneys.

And they actually accelerate the breakdown of old bone, the resorption part.

So less building, more breaking down, and less raw material.

That sounds bad for bone health.

It is.

People with Cushing's syndrome, that's a condition with way too many glucocorticoids, usually from a tumor or people on high doses of synthetic glucocorticoids for medical reasons, they often see a marked decrease in bone mass, increased risk of osteoporosis.

Which is the softening and weakening of bone.

Correct.

And this is especially problematic for older people, where bone breakdown naturally starts to outpace building anyway.

And particularly for postmenopausal women, because dropping estrogen levels also reduce the natural inhibition of bone resorption.

So adding high glucocorticoids on top of that, it's the last thing you need.

So is this only a risk with really high medicinal doses?

Or can everyday stress affect bones?

That's the crucial question.

For a long time, many clinicians thought these were mainly pharmacological effects, only seen at very high unnatural levels.

But more recent work, studies on female monkeys under chronic social stress suggest they can lead to bone loss.

Wow.

So it raises the possibility that even normal physiological levels of stress, if chronic, could actually damage our bones over time.

It certainly raises that concerning possibility, yes.

And there's also a difference in how growth hormone itself behaves during stress in humans versus rats, right?

There is, yeah.

It's quite interesting.

In rats, you stress them, GH levels drop almost immediately and stay low.

But in humans, GH levels actually go up for a period right after the stress starts.

Then with prolonged stress, they decrease.

Why would GH go up initially during stress?

That seems counterintuitive if growth isn't the priority.

Well remember, besides promoting tissue growth, GH also has another important job,

mobilizing energy.

Ah, okay.

How does it do that?

It breaks down stored fats in our fat cells, releases fatty acids and glycerol into the bloodstream, and those are fuel, especially for exercising muscle.

So during acute stress, like needing to run secreting GH makes sense for quick energy.

Exactly.

It's adaptive for immediate energy mobilization, but long -term expensive growth during that emergency, not adaptive.

So how does the body manage that, get the energy without the growth?

It's clever.

While GH is secreted for energy, the body simultaneously blocks the release or the action of the somatoma dins, remember?

Those are the hormones that actually mediate GH's growth effects.

So it uncouples the two functions.

Precisely.

Or tissue sensitivity to somatomedins declines during stress.

So you get the energy benefit of GH without accidentally triggering growth when you really shouldn't be.

That's a neat trick.

Why does GH eventually decline then, even in humans with prolonged stress?

It's likely a compromise.

Maybe the somatomedin shutdown isn't absolutely perfect or complete.

So the body can only afford to use GH for energy mobilization for so long before it risks some undesired growth effects slipping through.

It's about finding that precise balance over time.

Coordinating everything just right.

Okay.

Okay, one last really fascinating area from the chapter.

This cross -cultural study by Landauer and Whiting.

Stressful childhood rituals and adult height.

That sounds like a surprising connection.

It really is a surprising twist.

Back in the 60s, they looked at non -Westernized societies.

They meticulously classified cultures based on whether they had physically stressful developmental rights for children.

Things like piercing, circumcision, scarification, temperature extremes, making them vomit.

Okay, pretty intense stuff.

Yeah.

And crucially, they tried to control for genetics and diet by comparing related ethnic groups.

Some with the rituals, some without.

And what did they find?

The results were really counterintuitive.

For stressful rituals done between ages 6 and 15, it seemed to inhibit growth.

Adults ended up about 1 .5 inches shorter on average.

Okay, that fits the general stress inhibits growth idea.

Right.

For rituals between ages 2 and 6, they found no significant effect on adult height.

But here's the shocker.

For stressful rituals performed on children under 2 years of age, it seemed to stimulate growth.

Adults in those cultures were about 2 .5 inches taller than adults in related cultures without such early life rituals.

Taller.

From stressful rituals, that seems completely backward.

It does, doesn't it?

Now, we have to be cautious.

There are potential confounding factors.

Maybe only the hardiest infants survive those rituals, creating a bias, or other cultural differences.

And there's no direct hormone data from these specific groups and rituals.

Right.

Caveats apply.

Definitely.

But many biological anthropologists interpret these findings as evidence that some types of stressors, particularly very early in human life, might actually stimulate growth under certain conditions.

So the relationship between stress and growth might be more complex than just stress is bad for growth, especially early on.

It suggests a much more nuanced picture, yes.

It challenges a purely negative view of all stressors, particularly in that very early developmental window.

Fascinating stuff.

Absolutely fascinating.

So maybe we can recap this deep dive a bit.

Yeah, let's bring it together.

OK, so we've seen growth isn't simple.

It's this complex, energy -hungry process managed by hormones like GH, some admittance, sex hormones.

Right, the whole hormonal orchestra.

Exactly.

Then we hit the stark reality of stress dwarfism, where severe emotional or psychological stress, not just lack of food, can literally stop a child from growing.

It messes with the hormones, makes cells unresponsive.

And those historical examples King Frederick, the orphanages, even the Peter Pan story, they just hammer home how vital emotional connection is.

Its absence can be as physically damaging as starvation.

Truly.

And the science backs it up, right?

Showing how simple touch, nurturing care can dramatically boost growth in premature infants, which leads us towards acknowledging the power of,

well, love in biology.

Yeah, that word keeps coming up.

We also saw how stress hormones, glucocorticoids, can harm adult bones, potentially raising osteoporosis risk, and how the body cleverly uses GH for energy during acute stress without triggering growth.

Not an adaptive switch.

Right.

And finally, those intriguing cross -cultural studies hinting that maybe, just maybe, certain early life stressors could paradoxically stimulate growth, adding this layer of surprising complexity.

So it really makes you think, doesn't it?

This raises a question for you, our listener.

What really stands out to you about how deeply our emotional world, right from infancy, literally shapes our physical bodies.

Yeah, and how might thinking about that change how we view those simple, everyday acts of care and connection in our own lives and for the people around us?

It's powerful stuff to consider.

It really is.

Just incredible how interconnected our experiences and our biology truly are.

Thank you so much for walking us through all that.

My pleasure.

Thank you.

And thank you for joining us on this deep dive.

We hope you found these insights valuable.

Until next time.