Because we don’t work outside like our
agrarian ancestors and limit sun exposure due to warnings from
dermatologists, we have become a vitamin-D-deficient society. Our skin
may be less wrinkled, but below the surface there are health
consequences. The bottom line is that we are much more likely to die
from disorders aggravated by chronic underexposure to
vitamin-D-producing sunlight than disorders aggravated by overexposure.
Studies are showing that vitamin-D deficiency is associated with
numerous health problems, such as osteoporosis, cancer, cardiovascular
disease, mental-health problems, multiple sclerosis, and diabetes.
Furthermore, because an efficient immune
system requires ample vitamin D, virtually any disorder mediated through
immune-system mechanisms will be adversely affected by the lack of this
nutrient. One such disorder appears to be pain. Specifically,
vitamin-D-deficient individuals tend to have more chronic pain, which
seems to be alleviated by vitamin-D supplementation. Although
understandings are still evolving, evidence indicates that vitamin D
regulates the synthesis of key immune-system molecules (called
cytokines) implicated in pain-associated inflammatory responses.
It is uncertain how much supplementation
can lessen the unique pain experienced by individuals with spinal cord
injury or dysfunction (SCI/D). For example, it may help in the shoulder
pain associated with pushing a wheelchair or too many transfers but have
little impact on neuropathic pain. Nevertheless, vitamin-D is a
nothing-to-lose-potentially-much-to-gain approach that, at minimum, will
enhance overall health.
Vitamin-D Deficiency
Vitamin-D levels can be measured through
a simple blood test - even available through Internet self-test kits
(e.g.,
http://www.zrtlab.com/vitamindcouncil/) or walk-in, lab-testing
services popping up in many locations. The test measures levels of a
specific vitamin-D metabolite called 25-hydroxvitamin D which the body
converts to biologically active vitamin D (see figure). Levels above 30
nanograms (one billionth of a gram) per milliliter are considered
sufficient, between 20-29 ng/ml insufficient, and < 20 ng/ml inadequate.
Using these criteria, scientists estimate
that one billion people worldwide lack health-optimizing vitamin-D
levels. At special risk are the elderly and individuals with dark skin
pigmentation, especially those who live in cloudy, northern latitudes.
Wintertime sunlight possesses little of the wavelengths needed to
produce vitamin D in much of the northern U.S.
In my case, moving from sunny Colorado to
the overcast Pacific Northwest resulted in my vitamin-D levels
plummeting to a health-affecting 15 ng/ml. When I relocated to
sun-drenched New Mexico a few years later, levels increased to 50 ng/ml.
Overall, if you don’t have sufficient sun exposure, closely monitor
vitamin-D levels and take corrective actions as needed.
Scientists speculate that people with
physical disability are more likely to have compromised vitamin-D levels
because the disability limits time outside in the sun. One study
indicated that individuals with chronic SCI were twice as likely to have
deficient vitamin-D levels compared to able-bodied individuals. Levels
apparently go down quickly after injury as demonstrated by another study
showing deficient vitamin-D levels in 93% of patients admitted to acute,
inpatient rehabilitation, including 21% who were considered severely
deficient with levels <10 ng/ml.
Vitamin D & Pain
Numerous studies suggest that vitamin-D
deficiency has a role in pain manifestation, including:
1) Dr. Vasant Hirani looked at the
relationship of pain and vitamin-D levels in over 2,000 adults aged 65
and older living in England, a cloudy country whose capital London is
further north than Winnipeg, Canada. Overall, as we age we become less
efficient in synthesizing vitamin D and converting it to its
physiologically active form. Hirani’s study indicated that moderate to
extreme pain was present in 53% of these elderly individuals and was
correlated with poor vitamin-D status.
2) Dr. Wei Huang and collaborators at the
Atlanta VA Medical Center and nearby Emory University evaluated the
effects of vitamin-D supplementation in 28 veterans with chronic pain
and low vitamin-D levels. Age averaged 46 years, 18 were men, and 20
were African Americans (reflecting this group’s tendency to possess
suboptimal vitamin-D levels). The average vitamin-D level was a
deficient 18.6 ng/ml. After receiving vitamin-D supplementation for
three months, levels increased to 26 ng/ml.
Subjects rated their pain before and
after supplementation using a 0 to 10 pain scale, in which 0
corresponded to no pain and 10 as worst possible pain. In addition, a
quality-of-life questionnaire was administered which asked about
physical functioning, the extent health interferes with work, bodily
pain, general health, vitality, social functioning, the degree emotional
problems interfere with work, and mental health. Finally, another
questionnaire was used to assess sleep quality, which is frequently
affected by pain.
Using the 0-10 scale, average pain levels
decreased from 7.1 to 5.7 after supplementation. Overall, subjects
reported fewer areas of pain and a decreased use of pain medications. In
addition, the results indicated an improvement in most of the
quality-of-life components listed above, including the pain
component. Finally, sleep improved after supplementation, e.g., subjects
took less time to get to sleep and slept longer. The investigators
concluded that “vitamin-D supplementation in veterans with multiple
areas of chronic pain can be effective in alleviating their pain and
improving sleep, and various aspects of quality of life.”
3) Individuals with SCI often experience
neuropathic pain due to neural-tissue damage. Although studies focused
on using vitamin-D to lessen such pain are limited, Drs. Paul Lee and
Roger Chen (Australia) examined vitamin-D’s potential to relieve pain in
51 vitamin-D-deficient diabetics. A common disorder in individuals with
SCI, diabetes frequently causes pain-generating, peripheral nerve
damage. Three months of supplementation increased vitamin-D levels in
subjects from an average of 18 to 30 ng/ml. Several pain measures were
assessed before and after supplementation, including a 0 (no pain) to 5
(excruciating pain) scale. Using this scale, pain levels decreased from
3.3 before supplementation to 1.7 afterwards, a 48% reduction.
Conclusion
Of the many therapies discussed in this
Healing-Options series, few have the potential to enhance the overall
wellness of individuals with SCI/D as much as vitamin D. In this era of
costly, side-effect-laden medicine, vitamin D is an extraordinary simple
way to augment health with a huge bang-for-the-buck impact - especially
for people with SCI/D who are prone to vitamin-D deficiency and the
manifold problems caused by this lack. Get more sun exposure, eat a
vitamin-D-rich diet, or take a supplement, and you’ll be healthier.
Adapted from article
appearing in December 2012 Paraplegia News (For subscriptions, call
602-224-0500) or go to
www.pn-magazine.com.
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