Vitamin
D: Maintains normal blood levels of calcium and
phosphorus
• Promotes bone mineralization
• May reduce high blood pressure
• Helps build strong bones
What
is Vitamin D?
Vitamin D, calciferol, is a fat-soluble vitamin. It is known as the
sunshine vitamin because it is formed in the body by the action of
the suns ultraviolet rays on the skin. Vitamin D is converted in
the kidneys to the hormone calcitrol, which is actually the most
active form of vitamin D. The effects of this hormone are targeted
at the intestines and bones.
Vitamin D requirements increase with age, while the ability of skin
to convert sunlight into Vitamin D decreases. In addition the
ability of the kidneys to convert calcidiol to its active form also
decreases with age, prompting the need for increased Vitamin D
supplementation in elderly individuals. One billion people in the
world are currently Vitamin D deficient.
What
does Vitamin D do?
The major biologic function of vitamin D is to maintain normal
blood levels of calcium and phosphorus. Vitamin D aids in the
absorption of calcium, thereby helping to form and maintain strong
bones. It promotes bone mineralization in conjunction with a number
of other vitamins, minerals, and hormones. Without vitamin D, bones
can become thin, brittle, soft, or misshapen. Vitamin D prevents
rickets in children and osteomalacia in adults, which are skeletal
diseases that result in defects that weaken bones.
Cardiovascular: Research
indicates that vitamin D may play a role in preventing or reversing
coronary disease. Vitamin D deficiency is associated with an
increase in high blood pressure and cardiovascular risk. When
researchers monitored the vitamin D levels, blood pressure and
other cardiovascular risk factors of ***9 people, of an average age
of *9 years for 5 years, they found that those people with low
levels of vitamin D had a *2% higher risk of a cardiovascular event
than those with normal vitamin D levels.
What
are signs of Vitamin D deficiency?
The use of sunscreen with a sun protection factor (SPF) of 8
inhibits more than *5% of vitamin D production in the skin. To
avoid vitamin D deficiency dermatologists recommend supplementation
along with sunscreen use.
The reduced pigmentation of light-skinned individuals tends to
allow more sunlight to be absorbed even at higher latitudes,
thereby reducing the risk of vitamin D deficiency. However, at
higher latitudes (above *0°) during the winter months, the
decreased angle of the sun's rays, reduced daylight hours,
protective clothing during cold weather, and fewer hours of outside
activity, diminish absorption of sunlight and the production of
vitamin D. Because melanin acts like a sun-block, prolonging the
time required to generate vitamin D, dark-skinned individuals, in
particular, may require extra vitamin D to avoid deficiency at
higher latitudes.
Vitamin D deficiency can result from inadequate intake coupled with
inadequate sunlight exposure, disorders that limit its absorption,
conditions that impair conversion of vitamin D into active
metabolites, such as liver or kidney disorders, or, rarely, by a
number of hereditary disorders. Deficiency results in impaired bone
mineralization, and leads to bone softening diseases, rickets in
children and osteomalacia in adults, and possibly contributes to
osteoporosis.