Vitamin D - Sunshine Vitamin Helps With Ailments
D, the "sunshine vitamin," has recently become a hot topic.
It was once thought to be a fairly well understood vitamin without
too many surprises. Most experts felt that it was important for
bones and growth and not much else. Recent research, however, suggests
that it might play a role in preventing or treating a long list
of ailments. Diabetes, heart disease, high blood pressure, multiple
sclerosis, cancer and chronic muscular and skeletal pain are just
some of the conditions that are being studied to find out if they
can be cured or improved by vitamin D. But even more surprising
than this long list of diseases which may be helped by vitamin D,
is the fact that many of us seem to be deficient in this vitamin.
This deficiency is puzzling, as it was assumed until recently,
that most people in developed countries were getting adequate amounts
of Vitamin D. After all, our main source of vitamin D is sunlight,
and most of us have easy access to the sun. And, in addition to
sunlight, we have vitamin D fortified foods such as milk, some cereals,
soy drinks and breakfast bars. So, why are so many of us deficient
in vitamin D? And, furthermore, what can we do about it?
To answer these questions, let's first review how our bodies process
and use vitamin D. Vitamin D can either be eaten, or made from a
"pre-vitamin D" when the sun's ultraviolet rays hit our
skin. It then goes through a multi-step process, in which it is
converted from a less active form to a more active form. Once it
is in the most active form, it acts like a hormone and helps the
bones to take in more calcium and become stronger, and, also acts
on the intestines and causes them to absorb more calcium into the
process of converting "pre-vitamin D" to the more active
form can break down at any of its several stages, but, for many
of us, there appears to be a problem during the sunlight phase.
The time of exposure to sun, the angle of the sun, a person's age,
percent body fat and skin pigment all affect this stage of vitamin
D production. Ten to fifteen minutes of direct sunlight exposure,
twice weekly, is needed to produce an adequate amount of vitamin
D, and, although this seems easy to achieve, it is easier said than
done. To get the best exposure to sunlight, it is necessary to be
in the sun during the summer season at midday when it is high in
the sky. It is also advantageous to live within 25 degrees north
or south of the Equator where the sun's rays are more direct. The
less direct the sun's rays, the less vitamin D we make. A study
of vitamin D blood levels of people living in Boston (42.2 degrees
north of the equator,) showed that during the winter months when
the sun is at a more slanted angle, no vitamin D was made. Other
studies of other areas more than 25 degrees above or below the equator
showed the synthesis of vitamin D to be less during the winter months,
and the farther away from the equator, the smaller the amount of
vitamin D that was made.
Sunscreen and clothing can also block UV light and decrease vitamin
D production. Most people living in a temperate climate, such as
in the United States, keep their skin well-covered with clothing,
especially during cold weather, and they use sunscreen liberally
when they actually do venture into the sun. Darker skin color, higher
body fat and age also slow down or block UV light's effect on vitamin
D synthesis. All of these factors can lead to low blood levels of
vitamin D and increase our need to get more vitamin D from our diet.
This is a problem, since vitamin D is almost absent from our food
supply. About the only foods which naturally contain vitamin D are
some fatty fish and a few varieties of mushrooms. Furthermore, there
are restrictions on the amount of vitamin D which can be used to
fortify foods, making it difficult to get what we need through fortification.
So if we cannot get enough vitamin D from foods or from sunlight,
then that leaves only one other solution to getting enough of this
Many nutritionists and doctors have been slow to push supplementation
since there is some confusion about how much and what form of vitamin
D should be recommended. The current recommendations based on the
adequate intake (AI) amounts are: 200 IU per day from infancy to
50 years of age, 400 IU per day from age 50 to 70, and 600 IU per
day for people over 70 years old. These amounts do not appear to
be enough, however. A person is considered to be getting enough
vitamin D when the amount of active vitamin D in the bloodstream
equals 75 nmol/L, and this does not always happen when these amounts
of vitamin D are consumed. Many nutrition experts feel that our
current guidelines are not high enough. Some have suggested that
even the very young should be getting 500 IU per day, and that the
elderly should be taking 1000 IU per day. Some researchers feel
people with darker skin pigmentation should get 2000 IU per day.
Others have suggested that everyone, regardless of age, needs at
least 1000 IU per day.
further confuse the issue, there are 2 forms of vitamin D that are
supplemented: cholecalciferol (vitamin D 3) and ergocalciferol (vitamin
D 2). Vitamin D 3 is the natural form, the same type that is made
in your skin. Vitamin D 2 is made in plankton under natural conditions.
It has about half the strength of vitamin D 3, and interestingly
enough, has been shown to be more toxic when it is overdosed. Both
vitamin D 3 and vitamin D 2 overdoses, however, are rare. At one
time, there was some concern that too much vitamin D could be toxic,
but recent research has shown that 10,000 IU per day can be taken
without any toxic effects.
So we are left with some unanswered questions about this vitamin.
We are not sure of how much or what form should be supplemented.
Furthermore, we are not completely sure what benefits we would receive
if we did take in more vitamin D. The best advice that can be offered
at this time is that if you suspect that you are not getting enough
vitamin D; get your blood level tested. If the test shows you are
deficient, then take whatever amount of vitamin you need to get
it to an adequate level. Although testing blood levels and taking
a prescribed amount of vitamin D, would involve some expense and
the cooperation of your doctor, this would be the best way of making
sure you are getting enough of this vitamin. It is possible to dose
yourself with over-the-counter vitamin D supplements without testing
your blood levels, and it would most likely not be harmful to do
this, as long as you did not take more than 10,000 IU per day. Testing
and then dosing, however, is a more accurate way.
There is an urgent need to find some answers to our questions about
vitamin D since supplementation is, for many people, the only way
they can reap the benefits of this vitamin. Hopefully we will get
more information as more research is done, and we will be able to
start preventing and treating some of the diseases mentioned earlier
in this article. After all, vitamin D supplementation would surely
be a simple way to treat a lot of chronic diseases that have stumped
us for many years.