Your body can produce its own vitamin D with the appropriate amount
of sun exposure.
Shorter daylight hours, increasing age and avoidance of sun exposure
can lead to vitamin D deficiency.
Vitamin D, though called a vitamin, is really (depending on its
form) a pro-hormone or hormone. Vitamin D is most commonly associated
with regulation of calcium and phosphorus metabolism and, therefore,
bone mineralization. As such, all calcium supplements should also
contain vitamin D. More recent studies also directly link appropriate
levels of vitamin D with healthy blood pressure, glucose levels,
immune function and responses to inflammatory stimuli. In recent
years, a vitamin D deficiency has been correlated with a variety
of other risks. For example, it is noteworthy that the incidence
of prostate, breast and colon cancers is higher in latitudes that
provide less sunlight.
There is growing consensus that the current recommended daily allowance
(RDA) of 400-600IU of vitamin D is insufficient; research suggests
that the RDA be raised to 600-800IU, with 1000IU for any adult with
no sun exposure.
The sun provides a simple and inexpensive way to get adequate vitamin
D without compromising healthy skin. It’s just a matter of
exposing the arms and legs to 5-15 minutes of sunlight two to three
times per week before applying sunblock. The combination of frequency
and duration should be altered for the sun’s intensity.
Aging is an important factor in the sun solution. Ultraviolet exposure
(specifically UVB) works by performing a chemical conversion in
the skin to produce pre-vitamin D, which then goes to the liver
and kidneys for conversion to the active form of vitamin D. Between
the ages of 18 and 80, there is a two-fold decrease in the amount
of pre-vitamin D produced by the skin’s response to sun exposure.
The aging effect is further complicated by the aging kidneys’
ability to perform the conversion to the active vitamin D form.
If exposure to the sun is not an option, good food sources are fish,
cod liver oil and foods fortified with vitamin D, such as milk or
orange juice. Vitamin D supplements are also available. Don’t
let the shorter days of winter compromise your health.
