Hey everyone, welcome to the Drive
podcast. I'm your host Peter Aia.
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>> Peter, welcome to another AMA. How you
doing?
>> Very good, thanks.
>> Good. Well, today we're going to talk
about the thyroid. So, this is something
that it seems like people hear about all
the time but really don't understand
well. And so I think what might be
helpful people before we get into it is
maybe just explaining why this is such a
complex complicated topic.
>> Yeah, I don't I mean I think there's
probably several ways to think about
that. Uh but certainly one reason is
that the regulation of thyroid hormones
is quite complicated. Um and that's true
for several reasons, but I'll state one
at the outset which is it's a hormone
system for which the Goldilocks
principle applies. Right? too much is a
problem and too little is a problem.
Now, conversely, if you think about
testosterone, you know, male androgens,
that's not the case, right? Um, there's
really no naturally occurring scenario
where you have too much of it. And by
the way, even when people are having
testosterone replaced, if you give them
too much, they generally just feel
better. Um, so it's not, you know, it's
actually a a more asymmetric um problem,
but the thyroid is is particularly
nuanced. Um, and there's a feedback
system in the brain that works a lot
like other hormones we we know about,
uh, including testosterone. But again,
um, a second thing that then makes this
really complicated is that you have an
inactive hormone. That is the thing
that's actually gets getting secreted by
the thyroid gland that gets converted to
an active hormone locally. Um, and by
the way, there are different ways that
it gets converted. So there are
different enzymes that convert it and
it's so so so I think that's that we're
obviously I we're going to talk about
all of these things. Um
I guess the other thing I would say is
how you interpret the lab test is a
little bit problematic. Um, again, when
you are looking at something like
uh estrogen, progesterone, or
testosterone, provided you're using the
right assay, like an LCMS um test,
you're you can very accurately measure
those hormones. Um, as we'll discuss in
the thyroid, that's not always the case.
Um, I would say another thing that makes
this complicated is the importance of
how symptoms fit into the diagnosis. Now
again that should be part and parcel
with every endocrine diagnosis. It's
just that the symptoms of you know low
estrogen and progesterone and
testosterone are much more uh apparent
and have fewer overlaps with other
potential diagnoses than than we see
with with uh with thyroid. So I think
when you take all of these things
together, it's it's um managing the
thyroid hormone is sort of a ripe
environment for ideologic battles and
pseudocience and sort of a little bit of
chicainery um when it comes to sometimes
practitioners doing more harm than good
when they're trying to treat patients.
Given that, it seems like the best place
to probably start is just explaining to
people what is the thyroid and what does
it actually do.
>> So, it's a small gland with two loes on
either side of your throat. Really
sitting on top of your voice box uh just
below the Adam's apple is really where
it it it starts and then it rises to the
side uh and then goes down the other
side. So it makes uh a hormone but
primarily the one that it makes is
called T4 and it's called T4 because it
has four iodines on it and um the
downstream of that effect is that the
this hormone regulates the metabolic
rate of basically every cell in the
body. So you can think of the thyroid uh
gland as the gain knob on your body's
metabolic amplifier. Um so it's not
really deciding what your cells do so
much as how loudly they do it. Um, so if
you have too little signal and
everything is basically going to run
cold and slow, your heart rate's going
to drop, your weight's going to probably
creep up, you feel like you're operating
at half capacity, you're low in energy,
etc. Too much of it, of course, and
again, it's not a big line between too
much and too little and everything goes
up. Everything's hot and fast. So, your
heart rate goes up. You might even have
unexpected weight loss, anxiety,
insomnia, uh, atrial fibrillation, all
sorts of things like that. Um, I'd say
kind of roughly like 5%
um of adults in the United States have
some clinically [snorts] meaningful
thyroid dysfunction. Um, so for that
reason, I mean, it's wildly prevalent
and that means by definition many people
listening to us right now um are are
experiencing that. Um, but as I've kind
of alluded to, I think it's one of the
more commonly mismanaged conditions I
see. Um, and that's obviously why I want
to spend a lot of time on it. We do see
a lot of patients come into our practice
um, who are being mismanaged in this
regard and I think by extension many
other doctors are probably seeing that
too.
>> Yeah. And so with that mismanagement,
it's almost like there's a lot of
disagreement around this, right? It's
not a super clean topic, not a super
clean biology in a way. And so why do
you think that this can be such a
contentious topic for doctors and people
to understand?
>> I think because the system is complex um
which is not unique to the body. Um but
when you combine that with the fact that
we don't have visibility into its moving
parts, I think that creates a bit of a
perfect storm. So as I kind of alluded
to, the gland mostly secretes an
inactive pro hormone T4. Um, and then
there's a decision about how much of
that hormone becomes the active hormone
T3. But that decision is happening
locally, tissue by tissue.
Um, now TSH, thyroid stimulating
hormone, is a great marker of whether
the gland is being told to work harder.
Um, but it's a step removed from what's
actually happening inside the liver, the
heart, the brain. Then there's also kind
of a real philosophical split. So
there's a camp of physicians I suppose
that think hypothyroidism is
underdiagnosed,
undertreated.
Um and then you know that's kind of the
when you're a hammer everything is a
nail camp right like any problem that
anybody shows up with. If you're
depressed if you're having GI issues if
you're you know having sleep pro
whatever the problem is it's
hypothyroidism. Um, at the other end of
the spectrum, you have a camp of, you
know, other folks who say, "No, no, no,
this is completely overdiagnosed,
uh, by this kind of everybody has
hypothyroidism school of thought." And
basically, we're only going to treat
hypothyroidism if it is so overt that a
medical school student after one hour of
an endocrinology class would be able to
make this diagnosis blindfolded. Um,
as you can probably imagine, I think
both of these schools are incorrect. Um,
and that there's a messy middle ground
where the truth probably lies. And the
goal of this podcast, of course, is then
to kind of walk people through the
physiology carefully enough um that you
can see both the grains of truth on each
side of those uh schools of thought, but
perhaps more importantly what they might
be missing and therefore where we can
hopefully land on uh a place to to treat
people.
>> Yeah. And so on that, it seems like for
a lot of people the first time they
start thinking about the thyroid is
they're either tired, gaining weight,
something just quote unquote doesn't
feel right. You do what anyone does and
they go to Google, they search it, and
there's a ton of people, a ton of things
saying, "Hey, there's something wrong
with the thyroid, their hypothyroid."
And so, how much can you actually tell
from some of those like generic symptoms
like that? Yeah, unfortunately almost
nothing about uh you know fatigue and
feeling off is specific to anyone organ
system or cause. Um and we see this in
formal blinded studies trying to
diagnose hypothyroidism purely off of
symptom clusters without any
biochemistry. So they essentially
couldn't distinguish hypothyroid from
uyroid meaning patients that have normal
levels of thyroid. Um the same
complaints show up with sleep
deprivation, iron deficiency anemia,
pmenopause and menopause related
symptoms. Um and the last one, by the
way, may be one of the single biggest
confounders in my practice, especially
since the timing often overlaps, but
that's maybe a later issue. Um but
what's going on inside the endocrine
system and how to fix it are actually
kind of different. So you do need the
rigor of multiple data sources. Um and
and I think that a lab first approach uh
rather than a symptom first approach is
more likely to get you in the high zone
of probability. Um again based on how
non-specific these symptoms are.
>> So I think it's a good place to then
kind of look at it clinically in your
practice. Right. So, where are you
seeing doctors potentially missing a
real thyroid problem? And where do you
see people on the other end going too
far in that other direction?
>> Well, look, I think a lot of medical
care misses real disease when it treats
a lab value in isolation from the
patient. So, dismissing somebody with a
patchy gland, positive antibodies, and a
family history because their TSH is, you
know, quote unquote normal at 4.2. Um,
and that's so that's a legit failure.
Um, but just as often I'm seeing the
overreach in the other direction. And
this is most visibly in this strand of
uh what people call functional medicine
that treats subclinical hypothyroidism
as close to basically a ubiquitous
finding. Um, so if you go looking,
you'll find practitioners who insist
that the standard TSH ranges are too
permissive and treat a borderline free
T3 or elevated reverse T3 as irrefutable
proof of tissue level hypothyroidism
regardless of TSH or regardless of free
T4 and sometimes regardless of symptoms.
So having decided that a patient has a
thyroid problem, they will build an
elaborate root cause narrative, gut
health, adrenal fatigue, toxic burden,
etc. around kind of a lab picture that
in a large share of cases is actually
within a normal variation or will
normalize on its own. So rather than
just kind of accepting that a person
doesn't have hypothyroidism when their
blood work comes back normal by
conventional standards, they will maybe
um use this kind of functional medicine
framework to um basically assume that
there's a problem at the level of the
conversion of T4 to T3 in the tissue.
Ask the question, what's driving the
conversion impairment? Um I think in
reality a large share of patients with
mildly elevated TSH will normalize
spontaneously
um on repeat testing and I think overt
treatment with standard thyroid hormone
is is not benign. It can actually cause
cognitive symptoms atrial fibrillation
which we've seen countless times bone
loss and more. Um, so I think both
failure modes are real and some patients
go, you know, from their family doctor
and, you know, get hit at one end of it
and then are driven into the clinic of a
quack who hits them with the other end.
And um, again, just to reiterate, I
think both extremes are are are likely
doing more harm than good. Thank you for
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