discussed how sunshine and sunshine-generated vitamin D are good for
individuals with spinal cord injury and dysfunction (SCI/D). For
example, previously I reviewed how the lack of sun exposure and the
vitamin-D deficiency that may ensue is associated with multiple
sclerosis (MS). This update revisits the issue, highlighting studies
that have emerged since then supporting this association.
In brief review, skin synthesizes vitamin D when
exposed to the ultraviolet-B (UVB) component of sunshine. UVB exposure
can vary greatly depending upon many factors, including time of day
(more midday), season (more in summer), latitude (more near the
equator), altitude (more in the mountains), weather conditions, and
In the case of latitude and season, if you live
north of about 37 degrees (roughly, a line from Richmond to
San Francisco), you will have little vitamin-D production during winter
months because the sunís zenith angle is so low that the atmosphere
absorbs most UVB rays before they can reach you. In my case, because I
live in sun-drenched Albuquerque, New Mexico (35 degrees) at
6,000-feet elevation, I will have at least some UVB exposure throughout
Because it is fat soluble, excess, sun-produced
vitamin D is stored in body fat and can be later used in sun-deficient
It should be emphasized that sun exposure, not
food, is our primary natural source of vitamin D. With the exception of
oily fish foods, (e.g., salmon, sardines, mackerel, and cod liver oil),
relatively few foods naturally contain much vitamin D. Although numerous
other foods, like milk, have been vitamin-D fortified, their consumption
is generally not enough to generate health-optimizing vitamin-D levels.
Overall, we have become a
vitamin-D-deficient society because most of us work indoors and have
been indoctrinated to avoid sun exposure. Unfortunately, the lack of
this nutrient is implicated in the development of numerous disorders,
including osteoporosis, cancer, cardiovascular disease, diabetes, and,
the focus of this article, multiple sclerosis..
Scientists have shown that vitamin D
plays a critical role in maintaining an effective immune system.
Virtually any disorder involving the immune system will be influenced by
the lack of this crucial vitamin. This appears to be the case for MS, an
autoimmune disease that causes the body to attack its own central
nervous system (CNS).
Although MS is
influenced by multiple interacting genetic, environmental, nutritional,
hormonal, immunological, and viral factors, its prevalence is strongly
correlated with exposure to UVB-containing sunlight capable of producing
vitamin D and, in turn, the factors affecting such exposure.
incidence increases the farther you live away from the equator; e.g.,
there is more MS in the northern than southern US. Growing up in the
north increases your odds of acquiring MS as an adult, but even as an
adult your risk can be lowered by moving south (e.g., from overcast
Seattle to sunny Phoenix).
In an example involving elevation, Swiss who live
at lower altitudes have more MS than those who live further up in the
mountains with greater exposure to vitamin-D-producing UVB radiation.
In a nutritional example, Norwegians who live near
the ocean and, as a consequence, eat more vitamin-D-rich seafood have a
lower MS risk than those who live inland, even though both groups lack
sufficient sunlight to generate vitamin D through much of the year.
correlations strongly suggest that vitamin-D deficiency is a key factor
in MS development and expression.
supporting the vitamin D-MS link include the following:
Studying 95,000 women, Harvard University scientists concluded
that vitamin-D intake was associated with a substantially reduced risk
of developing MS (2004).
Using the Department of Defenseís Serum Repository of over
seven-million individuals, Harvard investigators determined that
military personnel with higher vitamin-D levels were less likely to
acquire MS (2006).
A 2013 Iranian study showed that MS severity is correlated with
vitamin-D levels. Patients with lower vitamin-D levels tended to have
severe relapsing-remitting MS as opposed to the milder
relapsing-remitting form of MS, and were more disabled.
Finnish investigators demonstrated that high dose vitamin D
resulted in fewer brain lesions, less disability, and better walking
A French study (2012) showed that monthly high-dose vitamin D
resulted in a reduction in relapse rates. Those patients who obtained
the highest levels of vitamin D in their blood had a 75% reduction in
Swedish scientists determined that people with the highest
vitamin-D levels were 61% less likely to develop MS than people with low
Following up on observations indicating that the risk of
developing MS peaks in people born during May (i.e., gestation over the
winter) and decreases in those born in November (i.e., gestation over
the summer), English investigators showed that MS-inclined May newborns
not only had lower vitamin-D levels but also a greater number of
autoreactive immune cells, i.e., the type which can turn on the body
suggest that vitamin-D deficiency is associated with an increased risk
of developing MS or expressing MS symptoms. As such, if you are
concerned about MS, evaluate your vitamin-D levels (a simple test), and
if low, take a vitamin-D supplement or get more sun exposure. Itís a
no-brainer; the odds are it will help you one way or another.
Adapted from article
appearing in December 2013 Paraplegia News (For subscriptions, call
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