A lack of vitamin D, a nutrient that is generated primarily through
exposure to sunlight, helps boost the risk of heart attacks and strokes.
Experts estimate that up to half of adults and 30 percent of children
and teenagers in the United States are vitamin D-deficient. There is a wide
array of studies linking increased cardiovascular risk with vitamin D
deficiency. For example, recent data from the long-running Framingham Heart
Study indicated that someone with vitamin D levels below 15 nanograms per
milliliter of blood is twice as likely to suffer a heart attack, stroke or
other cardiovascular problem within two years compared to those with higher
Vitamin D is well known as the "sunshine vitamin" because human skin
makes the nutrient upon exposure to sunlight.
a.. U.S. News & World Report December 1, 2008
a.. Journal of the American College of Cardiology December 9, 2008;
Dr. Mercola's Comments:
I've been writing a lot about vitamin D lately, and that's
because I want it to sink in with each and every one of you reading this
just how important it is for your health. I even recorded a one-hour vitamin
D lecture on the topic to help clear up any confusion.
At this time there are at least 36 organ tissues in your body
whose cells respond biologically to vitamin D, including bone marrow,
breast, colon, intestine, kidney, lung, prostate, retina, skin, stomach and
One of these organs is also your heart, for which vitamin D is
There are a number of physiological mechanisms triggered by
vitamin D production through sunlight exposure that act to fight heart
disease, such as:
. An increase in your body's natural anti-inflammatory cytokines
. The suppression of vascular calcification
. The inhibition of vascular smooth muscle growth
And according to Dr. James H. O'Keefe, director of preventive
cardiology at the Mid America Heart Institute in Kansas City and the lead
author of the above study:
"There are a whole array of studies linking increased
cardiovascular risk with vitamin D deficiency. It is associated with major
risk factors such as high blood pressure, diabetes and stiffening of the
left ventricle of the heart and blood vessels. Inflammation is really
important for heart disease, and people with vitamin D deficiency have
Aside from heart disease, vitamin D influences up to 3,000 of
the 30,000 genes in your body, helping to prevent diseases ranging from
cancer to the flu.
Unfortunately, it's thought that over 95 percent of U.S. senior
citizens and African Americans may be deficient, along with 85 percent of
the American public.
How Much Should You Get (Hint: Don't Listen to the RDA)?
I recently did an expert interview and interviewed one of the
top vitamin D experts in the world, Robert Heaney, MD. He has been studying
vitamin D for over five decades and was one of the consultants that served
on the board in 1997 that actually made the recommendations for our current
vitamin D RDAs.
I won't be posting his interview till the spring but he told me
that over 98% of what is known about vitamin D was learned since 1997. This
was largely because prior to that time there was no simple blood measurement
to detect vitamin D levels.
Be that as it may, the current RDA for vitamin D developed by
the Food and Nutrition Board at the Institute of Medicine of The National
Academies is miserably insufficient as it is only:
. 200 IU for people aged 14-50
. 400 IU for people aged 51-70
. 600 IU for people over 71
The American Academy of Pediatrics has even recently doubled its
recommendation for vitamin D in children to 400 IU a day, and that is also
There's simply no way to reap any benefit whatsoever from these
abysmally low amounts.
Consider this -- in the summertime when you put on your bathing
suit and sunbathe, your body produces about 20,000 IUs of vitamin D!
You might wonder how long you need to sunbathe, well the answer
is that it depends and is highly variable. The time you need to generate
maximum vitamin D is how long it takes for your skin to turn the lightest
pink when you are outdoors. This is called the MED or minimal erythemal
dose. For some people it could be a few minutes while for others it may
actually be hours.
Once you have this exposure it makes absolutely NO SENSE to
continue to expose your skin to the sun as you will only increase your risk
of premature skin aging, wrinkling and skin cancer.
During the winter or times when you have no or very limited
exposure to sunshine, you can make up for the lack of sunlight by using a
safe tanning bed or taking a high-quality natural vitamin D3
How much should you take? 4,000-5,000 units per day is
appropriate for most adults. If you are very heavy you may need to double
that dose, and for children the dose can be half that.
Important Information About Vitamin D Testing
It's possible to overdose on vitamin D when you take it in
supplement form. Because of this it's very important that you monitor your
vitamin D levels by blood testing to make sure your levels are therapeutic
and not toxic.