Hi, I'm Dr. Tracey Marks,
a psychiatrist,
and I make mental health education videos.
Since the pandemic,
and the trend of working
and doing school from home,
have you had more trouble sleeping?
There could be many reasons for that,
but one reason that you might not be aware of
is having a low Vitamin D level
from getting less sun exposure.
In fact, even if your sleep
is about the same,
there's still a good chance
you may have become Vitamin D deficient
in the past two years
from spending more time inside.
Vitamin D is a hormone probably most well known
for growing or building strong bones,
but your bones also need calcium.
But Vitamin D has to be present for the calcium
that you ingest to be absorbed
in your intestines.
If you don't have enough Vitamin D,
you won't absorb enough calcium.
In addition to bone growth,
Vitamin D also affects your circadian rhythm,
also known as your body clock.
How?
Vitamin D is involved
in the pathways that produced melatonin,
which is the hormone
that regulates your body clock.
Also, some research suggests
that there may be a bidirectional relationship
between sleep and Vitamin D,
meaning low Vitamin D
can disrupt your sleep
and inadequate sleep
can lower your Vitamin D levels.
So they affect one another.
So Vitamin D is high up on the food chain
of importance for physical and mental health.
It's believed that circadian rhythm dysfunction
is one of the core features
behind depression and bipolar disorder.
So keeping your sleep schedule on track
is important for a lot of reasons
and you may have a hard time doing that
if you're deficient in Vitamin D.
How do you get enough Vitamin D?
You can get small amounts of it from food
like Vitamin D fortified milk
and oily fish like salmon.
The recommended daily amount of Vitamin D intake
should be between 400 and 800 International Units.
Three and a half ounces of farm raised salmon
contains about 500 International Units.
Wild caught salmon contains a little bit more.
A cup of milk is only about
100 International Units.
So in general,
food is not the best source of Vitamin D.
Instead, the predominant source of Vitamin D
comes from your skin.
When you go out into the sun,
Ultraviolet B rays
penetrate your skin
and react with cholesterol molecules
in the epidermis layer of your skin.
This chemical reaction converts
the cholesterol to Vitamin D3.
Here are some things that reduce Vitamin D production.
Pollution because pollution blocks the UVB rays.
Aging, sunscreen with an SPF of 30 or greater,
clothing that covers your entire body.
Gastric bypass surgery because this surgery
bypasses the part of the intestines
where the oral Vitamin D is absorbed.
Obesity with a BMI greater than 30
and then darker skin because melanin,
which is the pigment that darkens your skin,
it also protects the skin
from the damage
from ultraviolet light exposure.
But it also then reduces
the production of Vitamin D3.
The chemical reaction still happens,
but it means that the darker your skin is,
the longer you need to spend in the sun
to get the same amount of Vitamin D
as someone with lighter skin.
This brings me to the question
of how much Vitamin D
does your skin actually make?
This varies depending on
the time of day, the season,
and the angle the sun hits your skin,
which is influenced
by the latitude where you are.
The further away you are from the equator,
the less UVB rays penetrate the atmosphere.
So this means you have to spend even more time
in the sun to absorb enough UVB.
In some places during the winter months,
you can produce very little Vitamin D
through your skin.
For example, here in the United States,
Boston is located in a northern latitude.
If you live there,
you will likely only produce Vitamin D3
in your skin between the months
of March and October.
The intensity of the sun's UVB rays
varies throughout the day.
You want to aim for noon day sun,
which is when the sun is directly overhead.
But in general,
the greatest intensity occurs roughly
between 10:00 a.m. and 4:00 p.m.
So these are all factors that influence
how much Vitamin D your skin makes.
How much sun exposure produces the recommended amount?
Studies have shown that in summer and spring
with only about 20% of your skin uncovered,
meaning you're wearing normal clothes
with maybe your arms
and your lower legs exposed,
your body can make about the equivalent
of 1,000 International Units of Vitamin D
from 10 to 15 minutes of sun exposure.
If you show evidence of pinkness
in your skin from that sun exposure,
that pinkness suggests that your skin made
about 10,000 to 25,000 International Units
of Vitamin D3.
How long it takes for your skin to show pinkness
depends on how much melanin you have in your skin
and how intense the sun rays are.
A dark skinned person
living far from the equator
in the winter
may not be able to stay outside
long enough to get
1,000 or more International Units of Vitamin D.
If you do get a lot of sun exposure
like you go on a Caribbean vacation
or you participate in an outside sport,
you can tank up on a lot of Vitamin D.
Vitamin D is a fat soluble vitamin,
which means that your body can store it
in fat tissue for later use.
So if you get a lot of exposure
during the spring, summer and fall,
your Vitamin D levels will drop during the winter,
but you still may have enough to keep you
from becoming deficient.
If you can't get enough Vitamin D from the sun, though,
because you spend a lot of time indoors
or you have some other factors
that limit your production of it,
all is not lost.
You can take Vitamin D supplements
to make up the difference.
Some multivitamins will have Vitamin D in them,
but usually in low doses.
So it's probably better to get a dedicated vitamin pill
that is 1,000 to 2,000 International Units
that you would take daily.
You can skip it
if you do something
that gives you a lot of sun exposure.
But even in people who have normal Vitamin D levels,
1,000 International Units a day is still
considered a safe amount to take.
You have to be careful taking more
than 2,000 International Units every day,
especially if you don't know your levels
because Vitamin D gets stored in your fat
and you can become toxic
if you accumulate too much of it.
Interestingly enough, your skin has
its own regulatory mechanism to keep you
from getting Vitamin D toxic
from a lot of sun exposure.
So the toxicity is only an issue
if you're taking high dose supplements.
If you get tested and are found to be deficient,
your doctor will likely prescribe a pill
that is 50,000 International Units
that you take once a week
for six to eight weeks.
So my own view is that it's always
best to get vitamins
and nutrients from food
and not pills if you can.
But in this case,
I think Vitamin D is one
of those important supplements
that is not as easy to get
from food or even the sun
given our indoor lifestyles.
And too much sun exposure
can be damaging to your skin
and sunscreen blocks Vitamin D's production.
So if you are someone
who likes to limit your supplements,
Vitamin D should be at the top of your list
and it's very cheap to buy.
If you live near the equator
and have an outside job,
you probably don't need supplements.
But when in doubt,
get your level checked
and get a specific recommendation
from your doctor about how much you should take.
Thanks for watching.
See you next time.