Fact:
Vitamin
D
Reduces
Breast
Cancer
Risk
A
connection
between
vitamin
D
level
and
the
risk
of
developing
breast
cancer
has
been
implicated
for
a
long
time,
but
its
clinical
relevance
had
not
yet
been
proven.
Sascha
Abbas
and
colleagues
from
the
working
group
headed
by
Dr.
Jenny
Chang-Claude
at
the
German
Cancer
Research
Center
(Deutsches
Krebsforschungszentrum,
DKFZ),
collaborating
with
researchers
of
the
University
Hospitals
in
Hamburg-Eppendorf,
have
now
obtained
clear
results:
While
previous
studies
had
concentrated
chiefly
on
nutritional
vitamin
D,
the
researchers
have
now
investigated
the
complete
vitamin
D
status.
To
this
end,
they
studied
25-hydroxyvitamin
D
(25(OH)D)
as a
marker
for
both
endogenous
vitamin
D
and
vitamin
D
from
food
intake.
The
result
of
the
study
involving
1,394
breast
cancer
patients
and
an
equal
number
of
healthy
women
after
menopause
was
surprisingly
clear:
Women
with
a
very
low
blood
level
of
25(OH)D
have
a
considerably
increased
breast
cancer
risk.
The
effect
was
found
to
be
strongest
in
women
who
were
not
taking
hormones
for
relief
of
menopausal
symptoms.
However,
the
authors
note
that,
in
this
retrospective
study,
diagnosis-related
factors
such
as
chemotherapy
or
lack
of
sunlight
after
prolonged
hospital
stays
might
have
contributed
to
low
vitamin
levels
of
breast
cancer
patients.
In
addition,
the
investigators
focused
on
the
vitamin
D
receptor.
The
gene
of
this
receptor
is
found
in
several
variants
known
as
polymorphisms.
The
research
team
of
the
DKFZ
and
Eppendorf
Hospitals
investigated
the
effect
of
four
of
these
polymorphisms
on
the
risk
of
developing
breast
cancer.
They
found
out
that
carriers
of
the
Taql
polymorphism
have
a
slightly
increased
risk
of
breast
tumors
that
carry
receptors
for
the
female
sex
hormone
estrogen
on
their
surface.
No
effects
on
the
overall
breast
cancer
risk
were
found.
A
possible
explanation
offered
by
the
authors
is
that
vitamin
D
can
exert
its
cancer-preventing
effect
by
counteracting
the
growth-promoting
effect
of
estrogens.
Besides
its
cancer-preventing
influence
with
effects
on
cell
growth,
cell
differentiation
and
programmed
cell
death
(apoptosis),
vitamin
D
regulates,
above
all,
the
calcium
metabolism
in
our
body.
Foods
that
are
particularly
rich
in
vitamin
D
include
seafish
(cod
liver
oil),
eggs
and
dairy
products.
However,
the
largest
portion
of
vitamin
D is
produced
by
our
own
body
with
the
aid
of
sunlight.