Vitamin D vital for brain development
Vitamin D vital for brain development
WASHINGTON: Vitamin D has been known to prevent rickets and promote healthy bones by regulating calcium levels in the body.
But it has been found to play a much broader role than thought
previously, for example, in the proper functioning of the immune system
and in development of the brain.
Evidence continues to pile suggesting that it also protects against
autoimmune diseases, including multiple sclerosis and type I diabetes,
as well as some forms of cancer, particularly colorectal and breast.
In fact, over 900 different genes are now known to be able to bind
the vitamin D receptor, through which vitamin D mediates its effects.
In a definitive critical review, Joyce C. McCann, and Bruce N. Ames,
of Children`s Hospital Oakland Research Institute (CHORI) conclude that
there is ample evidence to suggest an important role for vitamin D in
brain development and function.
Vitamin D is present in only a few foods (e.g., fatty fish), and is
also added to fortified milk, but our supply typically comes mostly
from exposure to ultra-violet rays (UV) in sunlight.
UV from the sun converts a biochemical in the skin to vitamin D,
which is then metabolised to calcitriol, its active form and an
important hormone.
Formation of vitamin D by UV can be six times more efficient in
light skin than dark skin, which is an important cause of the known
widespread vitamin D deficiency among Afro-Americans living in northern
latitudes.
Dark skin has been selected during evolution because it protects
against the burning UV rays of the sun in the tropics. White skin has
been selected for allowing as much UV exposure to make sufficient
vitamin D in Northern (high) latitudes.
Thus, fair-skinned northerners are at risk in Australia or Arizona
for sunburns and UV-induced cancer, while dark-skinned people in the
Northern U.S. or European latitudes
These conclusions will appear Tuesday in the Federation of American Societies for Experimental Biology Journal.
