Country Roads

Renee Kiff
Where would we be without our calendars? Reminding us to send
birthday cards, be on time for appointments, turn the clock ahead —
they keep us ordered and organized. They also are essential for
draining spaghetti. Oh? No? That’s a colander, not a calendar.
Sorry.
Calendars and the addition of maps are helpful in determining
something we all need — vitamin D3.
Most of humankind receives their essential vitamin D from its
source, Ultraviolet B radiation emanating from the sun. The
biologically correct explanation: “Ultraviolet (UV) B radiation …
penetrates uncovered skin and converts cutaneous
7-dehydrocholesterol to pre-vitamin D3, which in turn becomes
vitamin D3.” (Cellular and Molecular Biology; American Journal of
Clinical Nutrition; Current Opinion in Endocrinology and
Diabetes)
By providing vitamin D, the body is able to absorb calcium which
is essential for healthy bones. Besides calcium, vitamin D also
controls phosphorous in our blood. According to eHow, Pauline Gill
writes (and there is no telling what her credentials are – she
could be a column writer or a chicken farmer) “Vitamin D helps
protect the body from high blood pressure, cancer, heart disease
and autoimmune diseases.”
This poses a dilemma. Since the sun is “the only listed
carcinogen that is known to have health benefits” — National
Institute of Health’s llth Report on Carcinogens, what occurs when
we succeed in blocking it out by use of a hat and sunscreen?
Sunscreens with a protection factor of 8 or more blocks most UVB
rays. Shade, from a hat, reduces the rays by 60 percent. So, it is
possible, by use of both, to deny the body’s requirement of vitamin
D.
Geographic area also dictates exposure risks. Sunlight north of
an imaginary line crossing from the Northern California border to
Boston is too weak for the needs of vitamin D synthesis from
November through February. South of a line from Los Angeles across
to Columbia, South Carolina, one can reap the sun’s production of
vitamin D all year long. Smog and cloud cover will affect the
efficiency — complete cloud cover reduces UV energy by 50 percent;
shade or smog by 60 percent.
Additional factors to be considered in the necessary amounts of
vitamin D include skin color. An individual with fair skin can
obtain adequate exposure in ten minutes at high noon on a summer
day. Darker skin will require a longer time.
Depending upon where we reside, the strength of the sun
determines the amount of UV rays. Summer peak radiation can be one
thousand times higher than winter.
So, before we burn our hats and dispose of our sun screen, we
need to be reminded of why we wore those in the first place. The
Department of Health and Human Services reports that “broad
spectrum UV radiation is a carcinogen thought to contribute to most
of the estimated 1.5 million skin cancers and 8,000 deaths due to
metastatic melanoma that occur annually in the United States.”
Moreover, the American Academy of Dermatology advises “use
sunscreen whenever one is exposed to the sun.”
The best online site for extensive information about vitamin D
is located at ods.od.nih.gov/factsheets/VitaminD,
from the National Institute of Health (NIH). Contained in this site
are suggestions for foods containing vitamin D, such as fortified
milk, salmon, tuna, egg yolk; as well as many charts presenting
optimal amounts of necessary vitamin D intake.
For example, NIH recommends 400 IUs (International Units) for
children 0-12 months; 600 IUs for people 1 year to seventy; 800 for
seventy and over.
Now I understand why mom gave us a tablespoon of memorable cod
liver oil every morning. It contained 1360 IUs of vitamin D!
To conclude: everyone needs to eat a balanced diet; older folks
should have their doctor check their vitamin D level through a
blood test, taking supplements if you need them; and outdoor sun
time.
For those of us outdoors for many hours, it is imperative that
we exert moderation regarding sun exposure. As the calendar assists
us organizing the garden, we might consider the colander. It’s
perforated. It may be the answer to just the right amount of UVB
rays if we wear it on our head a half hour every day.
Renee Kiff weeds and writes at her family farm in Alexander
Valley.