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      Ultraviolet Radiation, Vitamin D and Rickets
                                                                             or
                                   

                                     Where did fair haired people come from ?

The hereditary factors of the early human being in Africa were formed  by the
African life conditions, among other things by the hot African sun

Our African ancestors left in early times the shadow jungle and settled  in the
 more food rich Savanna.They had  to adapt to  the hot,  shadeless Savanna
and lost in a process of evolution their animal'  hair dress.
( Not provablen, but could be)

An advantage: The naked sweating skin  improved  its  ability for  cooling, a
needed for long distance hunting.
A Marathon race in midsummer Australia (TV) Desert, blue  sky. A man can
do it, if he drinks sufficient water. A dog can´t stand the  whole  distance .Its
coat is the limit.  It can evaporate primarily water only on the tongue.

The price:The hairless skin is suspended in the Savanna directly to a deadly
sun  radiation. To survive, a  black  skin is necessary. By storage  of a 
black
coloring  material  (Melanin)   the  skin   was   protected. This  black  Melanin

absorbs about  85 % of the ultraviolet (UV) radiation and prevents
thereby an
otherwise deadly sun burn. An  obviously  necessary and effective
 
protection,
for
a white-skinned naked Irish will probably not survive for a longer time.

Later the African early human left its  southern  homeland  and  migrated in a
course
 of  thousands  o f years  gradually  northward,  step  by  step The sun
became weaker
and weaker and  the skin color changed.
The African  BLACK changed   toward s
a  Mediterranean  BROWN. In  the
high north. Within the ´isolated´ western area
of the Baltic Sea, the immigra-
ting  post  glacial  Magdalénean   reindeer  hunter
  became  a  pale  Scandi-
navian  WHITE.

This change in skin color was enforced by
a typical ´nordic´  illness, caused
by a lack of vitamin D
. The Rickets.
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Vitamin D is a steroid hormone that is produced in  the skin by the action of
sunlight's ultraviolet rays .Vitamin D plays  an  important  role  in  the metabo-
lism of calcium. In its absence, the deposition in the bones does not proceed
normally, and  the softened  bones become curved and  stunted
A narrowed chest  and  pelvis may  be responsible later in life  for increased
susceptibility to lung diseases and difficulties in childbearing.


Vitamin D supplement, usually with milk,has  been important in preventing
the incidence of rickets  in the northern and  temperate climates
. In 1924 it
was demonstrated that curative effects of ultraviolet light  resulted  from the
formation of vitamin D by such irradiation. Pure vitamin D 2 was first iso-
lated
n 1930-31 in England and in Germany.

                      

dunkle Oberhaut = dark skin,
Unterhaut-Fettgewebe= hypodermic fatty tissue
Knochen= bone

Ostsee= Baltic Sea

A dark skin may absorb up to 85 %  of the ultraviolet radiation.The quantity of
vitamin D synthesized in the region of the hypodermic fatty tissue may remain
stable as  long  as  radiation  and  skin coloring changed  n the same way,
approximately according to the function                    

           Amount of Vit.D = function of [UV-radiation / skin color]

If so, then vitamin D becomes -even in the North- sufficiently synthetized and
the necessary daily amount of calcium can be absorbed in the intestine and
be deposited over the bloodstream in the bone. The bone can  harden. If not,
then  an imperfect calcificatiom, softening  and  distortion  of the bones may
result (Typically bowed legs)
                          Darwin´s Theory  *Adapt or Perish*

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According to Darwin´s Theory there are two functions, which enforce genetic
adaptation of the  hereditary  characteristics  of  an  organism to the environ-
ment. It is the interaction between mutation and selection

Mutation (change) Life  originated in  the form of  primordial organisms that
were very simple and very small. All  living  things have  evolved  from  these
lowly beginnings. At present there are more than 2,000,000  known species,
which are  widel y diverse  in size, shape, and  way  of  life, as  well as in the
DNA sequences that contain their genetic information.


The information encoded in  the  nucleotide  sequence of  DNA is, as  a rule,
faithfully reproduced during replication, so that each replication results in two
DNA molecules that are  identical to  each other and  to the  parent molecule.
But heredity is not  a  perfectly  conservative  process;  otherwise, evolution
could not  have take n place.  Occasionally "mistakes,"or mutations, occur in
the DNA  molecule during replication, so  that  daughter cells may differ from
the  parent  cells  in  the  sequence or  in  the  amount  of DNA.
Mutation first
appears on a single cell of an organism, but it is passed  on to  all cells  des-
scended from the first.
(Encyclo. Brittannia)

Selection What  has produced  genetic  variation within natural populations
and the genetic differences among species? There  mus  be  some evolutio-
nary   means  by  which  existing   DNA  sequences  are  changed  and  new
sequences  are  incorporated  into   the gene pools of species.
For  instance  a decrease of number and size of  cells  producing  the  black
Melanin in the skin.

In  case  of  skin  complexion  the   effect  of  selection is obvious. Increased
Melanin
pigmentation is advantageous to inhabitants of tropica Africa,where
dark skin
 protects  them  from  the sun's   ultraviolet radiation; but is not ben-
eficial in
Scandinavia, where the  intensity of sunlight is low and  light  skin is
needed to
support the synthesis of vitamin D. 
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          How dangerous had been the Rickets in northern Europe?

In pratice. Assumed the average value of the skin  colouring in the gene pool
of a population  amounts   to 100 +/- 1. Supposed  furthermore   that  - due  to
mutation- two sisters differ genetically slightly  in  their  skin coloring. One has
a somewhat darker skin coloring factor of 101 and the other one is somewhat
brighter with a factor of 99. These  small ´accidental´ differences  in skin color
can hardly be recognized by a viewer, but this difference is  the biological tool
of selection.

An example.
Less UV- radiation penetrates the skin of  the sister with a  somewhat darker
skin of 101. Consequently less calcium is stored in her bones  and her pelvic
cavity might be  restricted by  rickety  deformation  of  her  pelvic  bones. In its
worth case,  she can´t give   birth to a  child. She  dies  under  the birth
  In the
North   her  ´dangerously  ´colored   skin   factor  of 101 is  not transmitted , is
´deselectet´. 
In  the course of  thousands of years the origenally more Mediterrean colored
gene pool of the immigrating and than isolated post-Magdalénian   becomes
typical.  After Tacitus:" All are  blue-eyed and fair-haired"..

Even  to  day our  babies in  northern  Europe are  further   endangered  by
Rickets.
Therefore they generally receive vitamin D tablets  during the first
18 months..Each
day one, in order to exclude the  danger of  rickets.
(I remember  with ' horror ' a
weekly spoon with sweetend cod-liver oil)

How much UV-radiation do we need?  Between  November and  February in
northern latitudes hardly vitamin D is synthesized in  the skin.  Mothers are in
particular endangered.They need a sunshine  exposition of 30 min on a clear
summer day against noon in a moderate climate.

During the quiet  time  mothers  may  lose  additional  calcium by insufficient
nutrition, because the milk gland extracts the necessary calcium for the baby,
about 400 mg per day  from the  mother  without ' consideration'. The danger
of a bone  softening  threatens,  particularly in  the  process of  several  preg-
nancies. Grandmother´s experience: Each  pregnancy one  tooth !
 Her best
´therapy´: Drinking MILK with its surplus of calcium.

                                  1 kg of   contains  mg calcium  
                                      
    beef                        110
                                         bread                      300
                                         full milk                1200
                                       
cheese                12000

Thereby  it  could  be  that  hunters  as  ´beef-eaters´  get  not enough  Ca,
while
milk as the main food of  cattle/dairy  farmer  provides  a  surplus of
calcium.
( Is the large body size of Tacitus´s  Northerners  due  to  lifelong
 milk drinking?)

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Objections

             Blond hair and blue eyes don´t synthezise vitamin D
                           Correct.Generally the
main objection)

But the trias of skin-hair-eyes  develops in  the outermost of the ectodermal
germlayer with masses of cells, which appeare early in  the
development of
an animal embryo.

In  vertebrates  the ectoderm  subsequently gives  rise  to hair, skin, and  the
lens
of the eye. Thereby conceivable that the Ectoderm as a whole becomes
darkened or depigmentated with more or less Melanin

Inui live in the  polar region.They have  little sun, long  winters , a  brown skin,
black 
hair and dark eyes however no Rickets, but their  food offers a surplus
of vitamin D
(among other things cod-liver oil)

Albinos
develop  not  by  selection and  mutation  but  by a  gene defect. The
synthesis of ectodermal coloring material is genetically imperfect. A too large
pathological jump in the normal mutation rate.

Black hair and blue  eyes. The gene  combination  of  black hair  with  blue
eyes results by crossing, not by selection.The procedure of a  crossing needs
a relatively short time, may be a  matter of  moments. The  effect of  selection
needs thousands  of years.

Wrong nutrition. Nothing is known about  the  level of  vitamin  D in the food
of northern Post-Madalénean reindeer hunter, but i t stands firmly that even to
day in the  North  the  population   can´t completely  compensate  a  deficit of
vitamin D with today´s nutrition.


Facit:
Selection  by
1.) Rickets
2.) genetic isolation
3.) along millennia
enforced
white skin, blue eyes
, fair hair in the North

Branda, R. and J. Eatoil  "Skin Color and Photolysis: An Evolutionary Hypo-
thesis,"Science,  201 1978

Neer, R. M. "The Evolutionary Significance of Vitamin D, Skin Pigment,
and Ultraviolet Light," American Journal of Physical Anthropology, 43. 1975


1-rickets 20.06.04 update

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Cattle may root a wood and thereby help Magdalénian to survive in the North
etr