VITAMIN D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced by the body when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis.
However, vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation.
The first occurs in the liver and converts vitamin D to 25-hydroxy vitamin D, also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D also known as calcitriol.
Vitamin D is essential for promoting calcium absorption in the intestines and maintaining adequate serum calcium and phosphate concentrations to enable normal mineralisation of bone and prevent hypocalcemic tetany.
It is also needed for bone growth and bone remodelling by osteoblasts and osteoclasts. Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults.
Together with calcium, vitamin D also helps protect older adults from osteoporosis.
We are now going beyond the skeletal system and going into the cardiovascular system. Vitamin D it appears, is good for the heart.
A new study presented on Nov 16 at the American Heart Association’s Scientific Conference in Orlando, Florida, confirmed a strong association between the presence of reduced vitamin D levels and a greater risk of coronary artery disease, stroke, heart failure and dying among men and women 50 years of age and older. Read more…
