From: altar@beaufort.sfu.ca (Ted Wayn Altar)
Subject: Re: Vitamin D from sunshine
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Thu, 7 Jan 1993 23:40:59 GMT

Paula Burch writes:

. . .
>Vitamin D deficiency used to be such a major problem that it was added
>to cow's milk as a supplement. This is hard to imagine since it's now
>said that you need only ten minutes or so a day of sunlight on your face
>hands and forearms, for six months of the year at New York City's latitude
>to take care of all of your needs for the year. If it's that easy to get
>enough, why did so many poor children get rickets? How strange that they
>were unable to get that tiny amount of sun exposure.

>I guess this really belongs under sci.med.nutrition.

Since the vegans here don't consume dairy products or eat fish or
meat, the worry has been raised about whether or not they are getting
enough vitamin D and whether or not they should take supplements.
Now, permit me to address your concern about rickets and sunshine.

There is good article in Scientific American, (Dec. 1970) by
W. Loomis who then said:

    The discovery of the cause and cure of rickets is one of
    the great triumphs of biochemical medicine, and yet its
    history is little known.  Indeed, it is so little known
    that even today most textbooks list rickets as a
    dietary-deficiency disease resulting from a lack of
    "vitamin D".  In actual fact RICKETS WAS THE EARLIEST
    AIR-POLLUTION DISEASE"  (emphasis mine)
    
    
The plain fact of the matter is that rickets is NOT caused
by a poor diet, as are all the other nutritional diseases,
but as Loomis says, by a "deficiency of solar ultraviolet
radiation"!

Solar ultraviolet may be blocked by many means, including
the industrial smog in London and the sunless alleys of
Wezlar.  In London as early as 1888 even the London zoo
animals -- chimpanzees, lions, tigers, bears, deer, rabbits,
lizards, ostriches, pigeons, and many more other species --
showed unmistakable signs of rickets.  Yet at that time a
little distance away in Dublin, Manchester, animals were
being raised without rickets.

Wezlar was a German Town of only 8,000 with exceptionally
narrow streets and dark alleys and consequently was infamous
in the early 19th century for its high rate of rickets.  The
children simply spent almost all of their life indoors and
rarely saw direct sunlight.  It is of course not surprising
that rickets become a major problem in such towns.

For centuries folk custom had taught northern European
mothers to put their infants out of doors even during
January for some "fresh air and sunshine".  Heck, I remember
my mother also trying to get me out of the house because I
needed some "fresh air and sunshine"  :-)   The problem,
however, occurred as the Europe became industrialized and
cities became highly polluted and over-crowded, making for
narrow streets dark streets and literally a blackened sky.
The old folk remedy was no longer effective due to human air
pollution plus poor urban design and overcrowding.

Thanks to the use of fuels that don't emit the same particulate
air pollution as coal plus the better design of our urban
dwellings and streets and we can get more direct sunlight
in our late 20th century cities -- well, maybe not LA  ;-(  --
than were the denizens of 19th and early 20th century
urban housing.  Maybe we should also add that the greater
acceptibility of skin exposure via shorts and the greater
cultural practice of outdoor leisure activity has also
made for more solar exposure.

While we are used to the notion of nutritional deficiencies
and worry maybe unduly about suffering from such
deficiencies, to think in terms of an "ultraviolet light
deficiency should be equally important.

Now, this is maybe a sensitive issue, but the impact of
ultraviolet irradiation on vitamin D in different racial
groups is quite marked.  For instance, 44% of the
ultraviolet light is transmitted through to the active part
of the skin in whites, but in blacks this value is only 3%
The reason why this might be a sensitive fact is that the
lunatic fringe bigot would argue that "nature" didn't intend
Blacks to live at northern latitudes.  But in point of fact
rickets and osteomalacia are not problems among, say,
British immigrant Black West Indians as it is among
Glaswegian Asians or some Canadian East Indians.  The reason
is simply differing cultural life-styles that while quite
advantageous or appropriate in one latitude are not so
advantageous in another.  Asian girls tend to be more
protected, more housebound and suffer the further exclusion
of a less yearly intense Northern sunlight by way of their
national dress.  Hence, it is a COMBINATION of climatic,
cultural, genetic and metabolic effects that act together to
precipitate this problem.  In Britain, the solution was to
supplement chapati flour with vitamin D.  This is better
than supplementing the entire flour supply, or the entire
milk supply and margarine supply as it is done
indiscriminately here in Canada.

I think we need choice on this issue.  If certain groups are
at risk due to their genetics and lifestyle, then by all
means they should have easy delivery of supplementation, but
to require the whole population to consume calciferol when
only a relatively very few need it, is simply rash when
alternative delivery methods to groups at high risk are
possible and when new evidence is coming in linking
calciferol with, atherosclerosis, osteoporosis and cancer.

                                        ted

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