Regarding the article “The power of
D” (SN: 7/16/11, p. 22), I was very surprised that there was no mention of
the positive effects of this vitamin
on the debilitating effects of depression. I have lived in northern latitudes
between upstate New York and now
Vermont since my birth in 1954. My
mother reminds me how she used to
worry about the annual return of my
severe depression as a young child,
which turned more serious in January.
I have childhood memories of colds,
bronchitis and pneumonia.
However, after attending a lecture
in Lenox, Mass., two years ago on the
subject of vitamin D, I have been taking larger doses of vitamin D and my
depression has virtually disappeared.
When my doctor learned that I was
doing this, he shared his concern about
potential toxicity. But tests showed my
blood levels for vitamin D were normal.
I would imagine that everyone has to
define the exact amounts right for their
body for themselves, but I do know that
this little golden and translucent pill
has saved my life.
Liz Winn, Marshfield, Vt.
Many studies have linked vitamin D
deficiency with depression. A German
study in 2000 found that people with
depression had lower levels of vitamin
D than those without the condition,
and in 1999 a U.S. study showed that a
megadose of vitamin D (100,000 IU)
resulted in improvement in depression
scores in people with seasonal affective disorder. A third study in Norway
in 2008 randomly assigned depressed,
overweight people to get vitamin D
supplements or placebos for a year
without knowing which. Those receiving vitamin D showed substantial
improvement; those on placebo did not.
— Nathan Seppa
In your five-page article on vitamin D,
you report that 30 minutes of exposure
to sunlight provides about 10 times the
upper recommended daily allowance
( 2,000 international units or IU recommended by the Endocrine Society)
of the vitamin, yet devote much of the
discussion of the appropriate level of
vitamin D to far less effective means
(natural and fortified food, and pharmaceuticals). Wouldn’t recommending
that everybody take each day a five-minute tan (free, less time-consuming
than other means of obtaining vitamin
D, and certainly not sufficient to get
a sunburn) render this whole matter
Ernst L. Leiss, via e-mail
In order to neither underdose nor
overdose on vitamin D, it seems to
make sense to measure vitamin D
blood levels before deciding on how
much to supplement.
Stan Rosenfeld, Fairfax, Calif.
In “The power of D,” two additional
aspects should have been included.
First, it is ultraviolet B sunlight, the
burning wavelength region, which
is necessary to create vitamin D in
our skin. During the winter, even in
southern regions of the United States,
it may be difficult to get enough exposure to ultraviolet B from the sun.
Second, you did not deeply discuss
concerns about exposure to high, possibly toxic levels of vitamin D supplements. I believe this issue involves
possible kidney damage, but I am not
aware of the evidence behind these
concerns. Such a discussion would
have further enriched your excellent
James P. Collman, via e-mail
Overdosing on vitamin D from the sun
appears impossible. The body has a
fail-safe mechanism that shuts down
the vitamin D–making apparatus in
the skin when levels are topped up.
Supplements are another matter, but it
still takes a lot to overdose on vitamin
D. Danish researchers in 1986 found
that people taking 4,000 IU of vitamin
D daily for two months ended up with
blood levels of about 45 nanograms per
milliliter, well within the normal range
and somewhat less than an outdoor
lifeguard would have all summer.
Reinhold Vieth of the University of
Toronto finds that his and other stud-
ies arrive at 10,000 IU a day as a safe
upper daily limit.
According to “Chemicals linked to kids’
lower IQs” (SN: 5/21/11, p. 15), neuro-toxic chemicals may lower children’s
IQs by up to 7 points. There is another
substance associated with a similar IQ
point difference in children, but no one
mentions it. The point spread between
breast-fed and formula-fed children
has been that large in some studies.
Parents are told about the IQ drop of
up to 7 points with pesticides. They’re
told about the IQ drop with low-level
lead exposure. Don’t they deserve to
know about the population-wide IQ
deficit linked to formula-feeding?
Maybe if they knew, they’d insist on
more than the mediocre breast-feed-ing help with which most women are
forced to make do.
Diane Wiessinger, Ithaca, N. Y.
I am a retired chemical engineer who
has had a subscription to Science News
magazine for a couple of years. It excels
in covering many science disciplines
concisely, understandably and timely.
Because it is valuable to my continuing
interest in science, I look forward to
receiving each issue.
William Scudder, Sarasota, Fla.
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