|
Vitamin D is a fat soluble family of compounds known as vitamins D1, D2
and D3. It is obtained from food, and, uniquely among the vitamins, it can be made in the
skin through the action of sunlight.
What does it do for your body?
The biologically active form of vitamin D is a hormone known as
calcitriol.
BONE - The most important role of vitamin D is to regulate the absorption and use of
calcium and phosphorus, which are vital for normal growth and development of bones and
teeth. Vitamin D stimulates intestinal absorption and reabsorption in the kidneys as well
as maintaining blood levels of calcium and phosphorus. It enables bones and teeth to
harden by increasing the deposition of calcium and may also assist in the movement of
calcium across body cell membranes.
THE IMMUNE SYSTEM - Vitamin D may also be involved in immune system regulation and play a
part in the prevention and treatment of infectious diseases. Parts of the bone marrow
which produce immune cells are receptive to vitamin D.
FERTILITY - Vitamin D is essential for strong pelvic bones and therefore plays an indirect
role in fertility.
HORMONES - Vitamin D plays a role in the secretion of insulin by the pancreas thus aiding
in the regulation of blood sugar. It also affects the parathyroid gland and a hormone that
it produces due to its calcium regulating role.
NERVOUS SYSTEM - Vitamin D ensures the functioning of healthy nerves and muscles by
regulating the level of calcium in the blood. Calcium is vital for normal nerve impulse
transmission and muscle contraction.
Absorption
When taken orally vitamin D is absorbed with fat through the intestinal walls. Vitamin D
can be stored the fat cells of the liver, skin, brain and bones in amounts sufficient for
many months consumption. Exposure to sunlight in spring, summer and autumn makes up for
any shortfall in dietary vitamin D and even short exposure to sunlight during these times
is adequate although there may be problems in winter months in some climates. Babies under
12 months have stores of vitamin D which they accumulate while in the womb.
The production of vitamin D in the body is blocked by anything which blocks ultra violet
light including skin pigment, smog, fog, sunscreen, windows and hats. |
