complex problem: Supplement and all will be well.
With about 40 percent of the world's population considered vitamin D
deficient (1), it does seem a tempting enough solution. If people
aren't getting enough Vitamin D, why not just pump it right into them
After all, without D, our bones grow weaker, our mental health
declines, and our incidence of disease rises, among other problems.
Doing nothing is surely not an option.
Unfortunately, vitamin D supplementation is ineffective at best and
produces dangerous vitamin D toxicity at worst.
Vitamin D Toxicity: How We Get Vitamin D
Vitamin D is sometimes called the sunshine vitamin because it can only
be created when the sun's rays strike our skin, putting it in the rare
class of hormones that use not enzymes as their catalyst, but
What Is Vitamin D?
Vitamin D is one of
the 13 known vitamins, but it's technically a hormone produced by the
body. While 11 of of the 13 vitamins are found in plant foods and can
only be taken in through our diet, D is one of the two -the other being
B12 - which does not conform to our traditional view of
When sunlight hits our uncovered skin, plant-derive sterols in it are
converted by the ultraviolet light into Vitamin D. The vitamin then
goes through processing in the liver and kidney to become
For millions of years, our ancestors made their home in equatorial
Africa, getting all the sunlight they needed by simply existing in
Over the course of hundreds of thousands of years, however, humans
started venturing out of their homeland, heading north and south into
lands where the strength of the sun varied greatly over the course of
Eventually, those who settled where the sun was weak during the winter
adapted to the low-light levels by losing their dark skin
pigment, allowing the body to absorb as much ultraviolet light as
possible. It's unclear if those in far northern and southern regions
were ever able to absorb enough vitamin D for optimal health, despite
their extremely white skin.
Vitamin D Toxicity: The Problem
Today, people have been
taught to fear the sun as a bringer of cancer.
Dermatologists tell them to hide their skin behind clothing and hats,
slathering any exposed skin with strong sun screen lotions, which
theoretically have the potential to block 95 percent of vitamin D
formation when applied regularly and consistently (2).
And during the last several centuries, our civilization has changed
from one where the majority people spent most of their waking hours
outdoors to one where most stay indoors while the sun is out, making
vitamin D production a challenge.
As our diets have worsened and the population's health has declined,
maintaining vitamin D levels has become even harder than it should be
under the circumstances.
Roughly a third of the U.S. population is now considered obese, with
more than 70 percent considered overweight. Because vitamin D is fat
soluble, excess body fat will pull vitamin D out of circulation, thus
contributing to deficiency (3).
Vitamin D Toxicity: How Much Do We Need?
How much vitamin D we need
has long been a matter of contention, and because it's clear that
taking too much causes vitamin D toxicity, and because these guidelines
are used to
judge who is deficient, it's an important question.
Vitamin D levels are usually measured by blood concentration. The most
common suggested levels are (8):
However, several researchers feel that that a level of 75-80 nmol/L
(30-32 ng/mL) may be sufficient (9).
Are these realistic guidelines? In my opinion, no. Even
healthy men and
women in Hawaii considered to have a large level of sun exposure
compared to the general population are unable to reach adequate D
levels under these requirements. In one study, they averaged a level of
31.6 ng/ml. The study's authors noted that 62 ng/ml was the highest
level achieved by any of the participants, which they suggested
may represent the upper healthy limit for anyone wishing to supplement
Another reason to question these guidelines is because people who don't
meet them often fail to manifest any signs of deficiency.
One study of women with seasonally-adjusted vitamin D concentrations
under 50 nmol/L (20 ng/ml), which would be considered deficient by
standard assessments, found they had no increased risk of fractures,
falls, decreased bone density, decreased grip strength, death, cardiac
problems, cancer, heart failure, diabetes, high or low blood pressure,
or increased weight (11).
Of course, it's entirely possible that other issues may be negatively
affected, but no great measure of evidence points to this. It's also
likely that, in the instance of the Hawaii study, greater levels could
be achieved if they exposed themselves to the sun even more frequently
than they are currently doing. It's unclear what benefits they would
derive from doing so.
Vitamin D Toxicity:
It's Clear There Are Consequences
what an actual healthy level may be, vitamin D
deficiency is causing problems. The pharmaceutical industry has
responded by attempting to fortify food with vitamin D and by geting
to take supplements, a high-profit area for them.
To some degree, this has worked well. By 1920, the role Vitamin D
played in preventing rickets, a scourge then affecting large parts of
the United States and Europe due to the reduced amount of time people
were spending in the sun, was discovered. In 1930 the U.S. government
mandated milk be fortified with 10 micrograms (400 IU) of vitamin D per
quart. The measure worked, and cases of rickets virtually
disappeared in the country. Today, rickets are making a comeback
because people are spending even less time outdoors than they were in
the 1930s, leading many to call for increased food supplementation.
Many adults now suffer from osteomalacia and osteoporosis,
which involve the weakening of mature bones. Both are considered
directly linked to vitamin D deficiency. Other disorders where D
deficiency is considered a contributing factor include cardiovascular
disease, cancer, increased overall mortality risk,
falls, diabetes, multiple sclerosis, osteoarthritis, epilepsy and
cognitive dysfunction (9).
The largest fear with D deficiency is bone health, yet in in a 2006
review, 5 of 9 studies looking to see if supplements would reduce the
risk of a hip fracture showed no decrease in breaks or overall
mortality (4). Other studies have shown that the benefits for bone
fracture prevention are small and largely restricted to
institutionalized elderly women and, and to be effective, the studies
must use a combination
of vitamin D and calcium, not vitamin D alone (5,7).
Even though there is an association between lower vitamin D levels and
increased risk of heart disease, strokes, type-2 diabetes, multiple
sclerosis, as well as breast, prostate, and colon cancer, supplements
have not been shown to be effective for these conditions (5-7).
The evidence that D supplements are not preventing or correcting the
problems caused by D deficiency has grown so strong that the medical
opinion in favor of them is changing.
In the March 2010 issue of the Annals of Internal Medicine, the
editorial concludes: "Despite the promise for disease prevention
suggested by available studies, we believe that the evidence for
widespread use of high-dose vitamin D supplementation in the general
population remains insufficient."
What researchers are finding is that supplementation easily raises the
level of vitamin D in the blood, but that this doesn't seem to actually
Vitamin D Toxicity: Supplementing Can Harm You
B12, which the body cannot overdose on, there may be significant
consequences that result from supplementing vitamin D: vitamin D
It's long been known that adults develop vitamin D toxicity
(Hypervitaminosis D) after several months of taking supplements of 1250
micrograms/day (50,000 IU). More recently, smaller doses are even
being reconsidered because even they might introduce vitamin D toxicity
and the attendent health problems.
A number of recent studies have shown that at dosages considered safe
(generally around 300-400 IU/day), increases
LDL-cholesterol, prostate cancer, immune system suppression, autoimmune
diseases, gastrointestinal symptoms, kidney disease, and calcium stones
has been observed caused by D supplements (13-19).
Whether or not this is recognized as vitamin D toxicity, there appears
to be some significant health consequences on the line.
Vitamin D Toxicity:
Then What Should We Do?
Because it appears that deficiency brings on disease but
ineffective at best and possibly harmful, we're left in a real bind.
Damned if you do and damned if you don't? Not quite.
Just like people are looking for quick shortcuts to a healthy body,
fitness, and weight loss, people want the quick fix for the D
deficiency. It's much easier to pop a pill than to actually adjust your
lifestyle to make yourself healthier.
It's no surprise that people who have higher vitamin D levels happen to
be comparatively thin, exercise, eat a relatively good diet, and
generally follow a healthy lifestyle (20).
Similarly, those who have lower levels of vitamin D tend to smoke, have
a parental history of heart attack (which often indicates that the
family norms passed on through generations include a high-fat diet),
drink alcohol regularly, and suffer from chronic illnesses (20).
As mentioned previously, overweight people are also much
more likely to
have a deficiency, and considering that most of the population of
western countries is overweight, this is a big contributing factor.
Researchers often note that those who have low D levels have an
increased risk of disease,
and although this is probably very true, the poor lifestlye that
kept them out of the sun probably contributed to their ill health.
The only safe course is to start changing your life to pursue health.
Vitamin D Toxicity:
The Power Of The Sun
There's no question that the sun exerts an incredibly positive
influence on us, helping our mind, cleansing out skin, and likely
providing us with aid that science does not yet understand.
In my ebook, The
Lifestyle, I talk about how the sun has successfully been
used to assist the body in healing itself in a number of ways, and give
suggestions for incorporating more of it into your life, no matter what
climate you live in.
I feel that it is the only safe way to provide ourselves with D.
Unlike supplement intake, it's virtually impossible to achieve vitamin
D toxicity through sun exposure under most circumstances (21). This is
because within about 20 minutes of ultraviolet exposure in
light-skinned individuals (or 3–6 times longer for darker-skinned
people) the concentrations of vitamin D precursors produced in the skin
reach an equilibrium, and any further vitamin D that is produced is
The amount of vitamin D produced through sun exposure at the point that
skin becomes slightly red has been estimated at 10,000 IU per day (21),
it's not clear how much of this is absorbed by the body.
Vitamin D Toxicity: But I Live In A Far Northern or Far
I live in Connecticut, where
it's likely impossible to generate vitamin D during much of the
although this is not absolutely certain. Many other are in similar
Vitamin D is fat soluble, and if you build up a good store it it, your
body will release it over the course of the winter, though in lower
quantities and quality than D generated by recent sun exposure.
How much D you have circulating during the winter is determined by how
much you produce during the spring, summer, and fall. For instance, you
need to achieve a blood concentration of 40 nmol/I during the
sunnier months to achieve a winter circulation of 15-22.5 nmol/l (23).
How long do our reserves last? By testing people stuck on military
submarines, where they can get no sun, researchers have determined that
it takes two months without sun to reach half-life, that state of
having our reserves reduced by half (24).
Generally, researchers believe a person can generate vitamin D
year-round in the area of land south of 37 degrees north and north of
37 degrees south. In the United States, 37 degrees north runs
close to Richmond Virginia on the east coast and Sanfransico on the
The farther outside of this band you get, the longer the period of time
during the winter when you can get no vitamin D. In Boston, for
instance it's believed that no vitamin D can be generated from late
October to early March. Wherever these periods last for four or
more months, it's possible that you will become deficient. People
living in these regions are more likely to be deficient than those
living closer to the equator, but the point to take home is that not
all of them are.
But even living in a sunny environment is no guarantee. Because people
don't venture outside much, even Australia, which gets tons of sunshine
by American standards, has a large D deficiency problem (9).
It's truly up to you to take the right steps and ensure you expose
yourself to the sun.
Vitamin D Toxicity: Steps You Can Take
The root cause of all vitamin D deficiency is a lack
of sun exposure. First, stop hiding from the sun and slathering on sun
screen. You don't have to worry about achieving vitamin D toxicity from
sun exposure. Simply don't allow yourself to get burnt, but gradually
build up a tan
for exposing yourself more and more each day. In most of the United
States you can generate D for three-quarters of the year. A low-fat
diet with tons of fruits and vegetables can help you not burn.
If you live beyond 37 degrees, the easiest way to
sidestep deficiency is to take a vacation to the tropics in the middle
of winter. A week of sunshine will restore your reserves and get you
through to spring.
If you cannot take a vacation but have wisely exposed
yourself to the sun every day during the spring, summer, and fall, it's
probable that you can make it through a three or four-month "vitamin D
winter" without any problems. Beyond this, you're likely in trouble.
When exposing yourself to the sun, don't listen to
the experts, who may suggest 5-10 minutes is sufficient. Realize that
those with darker skin pigments need much more than this, and that even
very white-skinned people develop tans that cut down on how quickly
they create D as they expose themselves. The key is never let yourself
burn. If you're not burning, you're not overdoing it.
Although there is no science to back it up, there may
be benefits to be derived from exposing as much of your body to the sun
as you can during the winter. I do this and feel that I benefit from
a sunny day in winter, running in a short-sleeved shirt is not
Vitamin D Toxicity:
There May Be No Easy Answer
People want to believe there must be a easy solution to this problem.
The fact remains that our species originated in the tropics, and
leaving them behind has degraded out health in a number of ways. It's
possible that living in the far north or south is inherently unhealthy
due to the lack of sun, and nothing we can do will make up for it.
although you will continue to see them vigerously
promoted, despite what science may have to say about it, because they
are extremely lucrative.
What about tanning beds? They generate vitamin
D on the skin, but they do not replicate the sun's rays, and it's hard
to say how they might affect us. Even so, I'd probably consider a
tanning bed before supplementing because it at least replicates the
basic process of generating D on the skin.
At the end of the day, we're back to the healthy living. Will you live
a healthy life? Will you keep your body fat levels low, eat a raw vegan
diet, exercise regularly, and otherwise create a good lifestyle? If
you do these things, your ability to deal with a any single deficiency
And if if you're unhappy about the amount of sunshine your home gets,
maybe it's time to consider a move.
Enjoy the sun :)
Learn more about the health-giving properties of the sun and how you
incorporate more of it into your life in The
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