Copyright (c) 2007 Ainsley Laing
I was doing some research on a topic that my
brother-in-law, an MD who works in university research,
mentioned to me over the holidays. Every time I see this
guy, he always gives me ideas! I came across a startling
introduction to an article written by John Cannell which I
thought I would steal:
What rat poison is safer than water?
The answer is … Vitamin D.
Turns out, there's a lot of new research on this vitamin
and, as my brother in law said, the research is indicating
that many of us need much more of this vitamin than we are
getting. Apparently, vitamin D plays a role in the
prevention of much more than just bone loss. Receptors for
vitamin D are found in most of the cells of the body. It
has been shown to contribute to a healthy immune system,
muscle strength and hormone production.
The major function of vitamin D is to maintain normal blood
levels of calcium and phosphorus. Vitamin D aids in the
absorption of calcium, helping to form and maintain strong
bones. Recent research also suggests it may provide
protection from osteoporosis, hypertension, heart disease,
certain cancers and several autoimmune diseases including
diabetes.
But here's speculation that I found really interesting:
vitamin D may help in weight control. You might have heard
of the study that cites that folks with more calcium in
their diets tended to have lower body mass indices (BMI).
Well, given that vitamin D is responsible for controlling
calcium levels in the blood, it follows that this vitamin
plays a role in the high calcium, low BMI phenomenon.
Researchers have also found that obese people have an
impaired ability to synthesize vitamin D from sunlight.
And, they are looking into the connection between excess
calcium deposits in the arteries (cardiovascular disease)
and low blood levels of vitamin D. Hmmm..
Vitamin D also plays a role in blood sugar regulation.
Swings in blood sugar signal our body's fat storage
mechanism and signals our brain to eat or not.
Don't we get vitamin D from sunlight?
Vitamin D is often called the sunshine vitamin because the
body synthesizes it from sunlight - specifically, from UV-B
rays. Yep, these are the ones we know as the burning rays.
In places further from the equator, these rays are most
available between 10 am and 2 pm. Most of us avoid
spending much time in the sun at these times because we get
sunburned which increases our risk of skin cancer and
premature skin aging. UV-B rays are blocked well by
sunscreens and by glass (glass doesn't block UV-As).
Depending on the pigment in your skin, it takes different
bodies different amounts of time in the midday sun to get
adequate levels of vitamin D. The darker your skin, the
more time you need in the sun to get enough of the vitamin.
So, now on to dietary vitamin D: Cod Liver Oil has a lot
of vitamin D, followed by some oily fishes, lard (pork
fat), butter, dairy fat and egg yolks. Beyond that, it's
pretty difficult to get enough of this vitamin from dietary
sources alone. So, if you work inside and wear sunscreen,
or live at latitudes far from the equator, supplementation
may a good thing.
But even supplementation recommendations are now under fire
by the researchers. The most common recommendations that I
have seen is 400 IU per day for kids, 200 IU per day for
adults under 50 years old and 400 IU per day for those over
50. Some researchers are advocating MUCH higher doses in
the 1000 IU to 2000 IU per day range! There is even a lot
of debate about toxicity levels of this vitamin among them.
Some say more that 2000 IU per day can be toxic, some say
20,000 IU per day is not!
I took a look at my super-duper Women's Multivitamin that I
buy at the health food store. It yields 400 IU per day. I
am 47 years old, live on the equator where there's lots of
UV-B rays much of the day, but work mostly inside and do
wear sunscreen every day. So, I have decided to be on the
safe side to increase my daily dose of vitamin D
supplements to 600-800 IU. This is below what researchers
are saying but above recommendations for my age. Remember
that when looking at this vitamin, it's important to keep
in mind the amount of midday sun exposure you normally get
on average, how far you live from the equator, how dark
your skin is and how much vitamin D your multivitamin
supplies.
Of course, I will keep checking in with my brother in law
and published research to keep track of any updates....and
will keep you posted.
Sources: The Vitamin D Newsletter 08/20/05. John Cannell
http://www.thaifoodandtravel.com/features/vitaminD.html The
Micronutrient Information Center, Linus Pauling Institute,
Oregon State University.
http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/inde
x.html The Mayo Clinic Newsletter, Drugs and Supplements
Section.
http://www.mayoclinic.com/health/vitamin-d/NS_patient-vitami
nd "The Miracle of Vitamin D" by Krispin Sullivan CN.
http://www.westonaprice.org/basicnutrition/vitamindmiracle.h
tml
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About the Author:
Ainsley Laing, MSc. has been a Fitness Trainer for 25 years
and writes exclusively Body for Mind eZine. She holds
certifications in Group Exercise, Sports Nutrition and
Personal Fitness Training. To see more articles by Ainsley
visit http://www.bodyformind.com
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