functional medicine and nutritional genomics - American Association ...

AAPI’S NUTRITION GUIDE TO OPTIMAL HEALTH: USING PRINCIPLES OF FUNCTIONAL MEDICINE AND NUTRITIONAL GENOMICS
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Vitamin D:
The Essential
Sunshine Nutrient
and Its Many Roles
Jay H. Mead, MD,
FASCP
Vitamin D is a fat soluble vitamin and prohormone
that exists in several different forms. Ergocalciferol
(Vitamin D2) is not produced in the body and
comes from plant sources, whereas cholecalciferol
(Vitamin D3) is found in cold water fish, such as
salmon, mackerel and sardines, is often fortified in
milk and is manufactured in the skin with
adequate exposure to the sun’s UVB rays i .
The New England Journal of Medicine estimated
that 30-50% of children and adults in the US are
at risk for vitamin D deficiency and 32% of
healthy adults age 18-29 were measured as
Vitamin D deficient at the end of a winter in
Boston ii . This is likely a consequence of
inadequate dietary intake
that may be exacerbated by fat malabsorption
coupled with insufficient exposure to UVB sunlight.
Note: Synthesis from sunlight requires that the sun
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be greater than 45˚ above the horizon and most
sunscreens block UVB rays. People with
increased melanin (darker skin) require longer
exposures to sunlight to produce the same amount
of Vitamin D.
Effects
Bioactive vitamin D binds to specific receptors in
the cell (known as VDRs or Vitamin D
receptors) iii and induces the transcription of more
than 50 genes iv
that have far reaching effects in
the body, including the follwing:
Osteoporosis / Calcium Balance – Vitamin D
increases intestinal absorption of dietary calcium,
increases reabsorption of calcium filtered by
kidneys and mobilizes calcium from bone when
there is insufficient dietary calcium. We have long
known the influence vitamin D had in formation of
bone, as evidenced by the incidence of rickets
with low Vitamin D levels v
.
2012