As I've been busy lately, mainly because I have been catching up with
homework at the University, I did not finish my comments to Erich's
message as soon as I usually would when working on a message like
this. Consequently Paul and Kitty let the message go without my
comments as they had not heard from me for 48 hours after finishing
their comments on the message and they suspected I was sick, as they
knew I had been recovering from a flu. I now realise that I probably
should've contacted Paul and Kitty saying that I had started working
on the message but was simply too busy to finish my comments soon.
Anyways here are my comments, finally.

--- In morelife@yahoogroups.com, "Erich Brueschke"
<erich_brueschke@...> wrote:
>
> Greetings:
>
> I am sure that both of you get the lef.org newsletter,
>
> [I have gotten the weekly "Update" newsletter since it began several
> years ago, but I wasn't aware that they had a daily newsletter. I see
> that it is mostly articles of news picked up from elsewhere and since
> those which are of high interest to life extensionists are generally
> posted to sci.life-extension (which I already check almost daily), I
> think getting the LEF newsletter will be information overkill for me.
> However, for many readers of this group who are not reading
> sci.life-extension and doing other research, this daily newsletter may
> be very worthwhile. --Paul]

I used to get LEFs daily newsletter but unsubscribed from it a while
ago since like Paul I am already getting so much information
elsewhere. I don't have time to read everything, also I prefer to do
my own research using pubmed. But when something very important or
interesting appears in LEFs newsletter I will probably not miss it as
someone on the sci.life-extension group or the MoreLife Yahoo group
will likely post it, like Erich just did now (thanks Erich).

> [There are new benefits of vitamin D coming out frequently. In
> addition, there is now good evidence that it is both safe and
> effective at much higher dosages than the RDA. I have recently once
> again increased the daily dose for me and Kitty by another 1000 IU,
> now up to 3351 and 3084 respectively. For us I think that may be
> sufficient since we get some sunshine on our skin all year round. --Paul]

I've been taking a total of 3336 IU of vitamin D for almost a year
now. I upped my dose to that level after reading some research
suggesting that such high doses are safe to take. Another reason I
upped my dose at that time is because I then realised that the amount
of vitamin D I was getting from sun exposure was very low and probably
far from being sufficient for me to maintain optimal levels of vitamin
D. Below I post a few abstracts in support of this.


J Lab Clin Med. 1989 Sep;114(3):301-5.
In vivo threshold for cutaneous synthesis of vitamin D3.
Matsuoka LY, Wortsman J, Haddad JG, Hollis BW.
Department of Dermatology, Jefferson Medical College,
Philadelphia, PA 19107.

Cutaneous vitamin D3 synthesis and release into the circulation is
promoted by skin exposure to ultraviolet B radiation (UVB, spectrum
290 to 320 nm). To determine the relation between UVB energy level and
cutaneous vitamin D synthetic response, we delivered graded increases
of UVB suberythemic radiant energy (3 to 27 millijoules/cm2 [mJ/cm2])
to 32 untanned young white subjects with skin type III
(Fitzpatrick-Pathak classification). Serum vitamin D3 was determined 1
hour before (basal value) and 24 hours after a single whole body
exposure to UVB in a phototherapy unit. The basal vitamin D3
concentration was similar in all individuals (mean +/- SEM for whole
group, 1.6 +/- 0.2 ng/ml). UVB irradiances were followed by
proportional rises in serum vitamin D3 (at 27 mJ/cm2, 14.3 +/- 3.7
ng/ml), and the overall correlation between UVB radiation and
consequent serum vitamin D3 response (r = 0.81; p less than 0.02) was
best described by an exponential function. The minimal UVB radiation
level that produced a significant increase in serum vitamin D3 was 18
mJ/cm2, a value similar to the lowest solar broadband UVB irradiance
that generates previtamin D3 in vitro from the precursor
7-dehydrocholesterol (20 mJ/cm2). Because in the northern United
States winter UVB irradiance does not generally reach this threshold
level, we conclude that individuals living at extreme northern (or
southern) latitudes may have higher dependence on body stores and
dietary supply to meet their vitamin D requirements during winter.

PMID: 2549141

In the abstract above the researchers determined the minimum level of
UVB radiation needed to produce a significant increase in serum
vitamin D3 in untanned white subjects. They then concluded that in the
northern United States UVB irradiance does not generally reach this
minimum level during the wintertime.


J Clin Endocrinol Metab. 1988 Aug;67(2):373-8.
Influence of season and latitude on the cutaneous synthesis of
vitamin D3: exposure to winter sunlight in Boston and Edmonton will
not promote vitamin D3 synthesis in human skin.
Webb AR, Kline L, Holick MF.
Vitamin D, Skin, and Bone Research Laboratory, Boston University
Medical School, Massachusetts 02118.

Sunlight has long been recognized as a major provider of vitamin D
for humans; radiation in the UVB (290-315 nm) portion of the solar
spectrum photolyzes 7-dehydrocholesterol in the skin to previtamin D3,
which, in turn, is converted by a thermal process to vitamin D3.
Latitude and season affect both the quantity and quality of solar
radiation reaching the earth's surface, especially in the UVB region
of the spectrum, but little is known about how these influence the
ability of sunlight to synthesize vitamin D3 in skin. A model has been
developed to evaluate the effect of seasonal and latitudinal changes
on the potential of sunlight to initiate cutaneous production of
vitamin D3. Human skin or [3 alpha-3H]7-dehydrocholesterol exposed to
sunlight on cloudless days in Boston (42.2 degrees N) from November
through February produced no previtamin D3. In Edmonton (52 degrees N)
this ineffective winter period extended from October through March.
Further south (34 degrees N and 18 degrees N), sunlight effectively
photoconverted 7-dehydrocholesterol to previtamin D3 in the middle of
winter. These results quantify the dramatic influence of changes in
solar UVB radiation on cutaneous vitamin D3 synthesis and indicate the
latitudinal increase in the length of the "vitamin D winter" during
which dietary supplementation of the vitamin may be advisable.

PMID: 2839537

According to this abstract human skin exposed to sunlight on a
cloudless day in Boston from November through February produces no
previtamin D3. Furthermore in Edmonton this ineffective period
extends from October through March. However according to a much more
recent abstract, one I had not seen before but post below, the length
of this ineffective period appears to have been overestimated in the
above abstract as the only way the authors could reproduce the results
of that study was by assuming that the column of ozone over Boston was
much higher than what would be expected at that time and location.

[I was surprised by that result for a city of the latitude of Boston, since if
that were really the case there would historically be much more evidence of
widespread vitamin D deficiency among peoples living in the north. In fact, such
a natural deficiency would surely have made northern inland areas of Asia and
Europe (without access to vitamin D from seafood) completely uninhabitable.
--Paul]


The
length of the ineffective period [stated for Boston in the above study] is
closer to what one would expect in
Reykjavik Iceland (where I live) which is located 64 degrees north. As
the abstract below states the degree of UV radiation and consequently
vitamin D synthesis depends on a lot of factors including latitude,
time, total ozone, clouds, aerosols, surface reflectivity and
altitude. The abstract furthermore links to pages on the Internet
containing a calculator which one can use to calculate the daily
duration of vitamin D synthesis at different times, locations and
conditions. It's a very interesting and useful tool.


Photochem Photobiol. 2005 Nov-Dec;81(6):1287-90.
Daily duration of vitamin D synthesis in human skin with relation
to latitude, total ozone, altitude, ground cover, aerosols and cloud
thickness.
Engelsen O, Brustad M, Aksnes L, Lund E.
Norwegian Institute for Air Research (NILU), Tromso, Norway.
ola.engelsen@...

Vitamin D production in human skin occurs only when incident UV
radiation exceeds a certain threshold. From simulations of UV
irradiances worldwide and throughout the year, we have studied the
dependency of the extent and duration of cutaneous vitamin D
production in terms of latitude, time, total ozone, clouds, aerosols,
surface reflectivity and altitude. For clear atmospheric conditions,
no cutaneous vitamin D production occurs at 51 degrees latitude and
higher during some periods of the year. At 70 degrees latitude,
vitamin D synthesis can be absent for 5 months. Clouds, aerosols and
thick ozone events reduce the duration of vitamin D synthesis
considerably, and can suppress vitamin D synthesis completely even at
the equator. A web page allowing the computation of the duration of
cutaneous vitamin D production worldwide throughout the year, for
various atmospheric and surface conditions, is available on the
Internet at http://zardoz.nilu.no/~olaeng/fastrt/VitD.html and
http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html. The computational
methodology is outlined here.

PMID: 16354110

[That is excellent information, Olafur. Particularly since Casa Grande, Arizona,
where Kitty and I spend the winters now, is just below 33' latitude and we get a
fair amount of winter sunshine while there. --Paul]

[I checked out the tool links above. I used the easy (ez) version to compare the
best of sun exposure (cloudless day) for us in Harcourt Park Ontario (alt 414m,
lat. 45' and long. 78.5') with Casa Grande AZ (alt 446m, lat. 33' and long.
112'), leaving ozone layer box at medium (don't know how to determine) and came
up with the following total hours:
Date.....414m, lat45', long78.5..........446m, lat 33', long 112'
9/20.............8.65 hr.......................9.25 hr
12/20............3.25 hr.......................6.25 hr
3/20.............8.35 hr.......................9.05 hr
6/20............11.55 hr......................11.05 hr

(One can find out the altitude of hir town fairly easily with a web search -
many weather reporting stations are listed and they do provide altitude.) The
tool also allows for calculation for other sky conditions and is so helpful that
I'll create a link for it on MoreLife.org.
For the last several days it's been almost entirely cloudy, often with rain. For
such conditions (and all other parameters equal) the tool states that the total
number of Vit D producing hours here in Harcourt Park is 6.95.

A note about the time labels for output. The start and stop hours for the total
number of hours given is labeled "UTC" ( Coordinated Universal Time
http://aa.usno.navy.mil/faq/docs/UT.html and
http://www.timeanddate.com/worldclock/ ) which is the same as GMT. (This gave me
a few minutes confusion but with some added research I now understand the
purpose of UTC. I've emailed the author in Norway with the suggestion that for
the EZ version meant for non-scientists, he change it to "UTC/GMT".) However, no
allowance is given for daylight savings time, so this will need to be kept in
mind by the user. Also, the UTC time is for the exact longitude entered. This
yields far more accuracy then simply using a time zone, makes the start and stop
times not equidistant from 12:00 pm (or 1:00 pm when on daylight saving time)
unless the user is in the center of hir time zone. Interestingly enough,
according to the output of the tool there is slightly more Vit D producing time
after the high point of the sun for the day than before. **Kitty]


According to the calculator linked to in the abstract, in Reykjavik,
at no time in the day is there strong enough UVB radiation for one to
synthesize significant amounts of vitamin D from mid October to the
beginning of March. This means that during this time of the year I
will have to rely exclusively on diet and supplements to get my
vitamin D. Not only that but even in the months when UVB radiation is
strong enough for vitamin D production here in Reykjavik the fact that
I avoid being outside in sunshine, particularly early in the day when
the sun shines at it's strongest, makes sure that even in the mid
summer I probably do not get optimal amounts of vitamin D from
sunshine alone.

As a result of this research I have now decided to
take an extra 1000 IU of vitamin D from October to March giving me a
total of 4336 IU in the wintertime. I also recommend to others, particularly
those who live at northern latitudes where "vitamin D winters" occur to take
higher doses of vitamin D during the winters as it will help them maintain
optimal levels of vitamin D throughout the year. I also plan to get my
1,25-dihydroxyvitamin D (the active hormonal form of vitamin D in the
body) level tested the next time I get an extensive blood test, which
unfortunately probably won't be until the next time I visit the US as
blood tests without any medical reason behind them generally are not
available in Iceland.

> But why? What is it about flu that means outbreaks only occur in the
> winter? Isolated cases occur throughout the year, as reported to the
> Royal College of GPs' Flu Monitoring Unit in Birmingham, proving that
> the virus is in constant circulation year-round.
>
> Now a group of researchers has come up with a novel answer to the
> conundrum. The "seasonal stimulus" behind the annual winter flu
> epidemics is a lack of vitamin D due to shorter days and lack of
sunlight.
>
> And they have even suggested that by taking a mega-dose of the vitamin
> at the first sign of the illness, its worst symptoms might be
> alleviated - which could prove to be a potential life-saver in the
> event of the threatened avian flu pandemic.
>
> The article also points out that:
>
> Vitamin D lowers insulin resistance which is one of the major factors
> leading to heart disease.
>
> It acts as an immunosuppressant and may help protect against the
> development of type 1 diabetes.
>
>
http://www.lef.org/news/LefDailyNews.htm?NewsID=4335&Section=VITAMINS&source=DHB\
_060916&key=Body+ContinueReading

Here is the relevant abstract:

Epidemiol Infect. 2006 Sep 7;:1-12
Epidemic influenza and vitamin D.
Cannell JJ, Vieth R, Umhau JC, Holick MF, Grant WB, Madronich S,
Garland CF, Giovannucci E.
Atascadero State Hospital, 10333 El Camino Real, Atascadero, CA, USA.

In 1981, R. Edgar Hope-Simpson proposed that a 'seasonal stimulus'
intimately associated with solar radiation explained the remarkable
seasonality of epidemic influenza. Solar radiation triggers robust
seasonal vitamin D production in the skin; vitamin D deficiency is
common in the winter, and activated vitamin D, 1,25(OH)2D, a steroid
hormone, has profound effects on human immunity. 1,25(OH)2D acts as an
immune system modulator, preventing excessive expression of
inflammatory cytokines and increasing the 'oxidative burst' potential
of macrophages. Perhaps most importantly, it dramatically stimulates
the expression of potent anti-microbial peptides, which exist in
neutrophils, monocytes, natural killer cells, and in epithelial cells
lining the respiratory tract where they play a major role in
protecting the lung from infection. Volunteers inoculated with live
attenuated influenza virus are more likely to develop fever and
serological evidence of an immune response in the winter. Vitamin D
deficiency predisposes children to respiratory infections. Ultraviolet
radiation (either from artificial sources or from sunlight) reduces
the incidence of viral respiratory infections, as does cod liver oil
(which contains vitamin D). An interventional study showed that
vitamin D reduces the incidence of respiratory infections in children.
We conclude that vitamin D, or lack of it, may be Hope-Simpson's
'seasonal stimulus'.

PMID: 16959053

I do not have access to the full text article but as the abstract
states what may be the most important effect vitamin D has on immune
function is it's stimulating effect on the expression of antimicrobial
peptides. I found some recent evidence that vitamin D directly induces
antimicrobial peptide gene expression in humans (PMID: 15322146, PMID:
15985530, PMID: 1649788). This effect may be particularly important
in the modern world of ever increasing development of antibiotic
resistant microbial strains as resistance of microbial strains to
antimicrobial peptides is highly improbable because of their mechanism
of action (they target the bacterial membrane).

[Thanks Olafur, for your, as always, excellent additional information. --Paul]