Vitamin D - "The Sunshine Vitamin"

"You are My Sunshine, My Only Sunshine . . ."

What are our sources of vitamin D?

• Sunlight.    For most people, the major source of vitamin D is the D3 form obtained from exposure to sunlight.   Humans and other vertebrates create Vitamin D3 (cholecalciferol) in their skin after exposure to ultraviolet B (UV-B) light (from the sun or artificial sources). 
• Vertebrate animal meat and oily fish.  In addition to sunlight, we can also obtain vitamin D3 form by consuming vertebrate animal or fish flesh.   But of the fish, only oily fish has any significant quantity
• Invertebrate meat, plants and fungi.  Invertebrates, plants and fungi create vitamin D2  form when exposed to UV-B radiation.   We obtain vitamin D2 by consuming these foods.
• Supplements.   Due to various limiting factors to sun-derived sources (e.g. fear of melanoma, amount of available UV-B radiation, exposure times, use of sunscreens), most people today fall short of their vitamin D needs without a dietary/supplementary source.    Supplemental D2 and D3 can be synthesized in a lab setting.  D2 only stays in the bloodstream a few days (compared to weeks for D3).     So one would need to supplement D2 regularly.

Enzymes in the body convert both D2 and D3 vitamins into CALCIDIOL 25(OH)D (its circulating D form), and then the kidneys (and also the cells to some degree) convert this to CALCITRIOL 1,25(OH)₂D (its active form)

Vitamin D Deficiency - A Silent Epidemic

How to Obtain Vitamin D

What does vitamin D do for us?

Vitamin D does much more than aid calcium absorption for bone strength

Vitamin D is important because of the many functions it performs in virtually ALL the body's cells

• Upregulates almost 3000 genes
• Aids absorption of several minerals -not just calcium
• Regulates immune system / inflammation
• Increases blood's oxygen-carrying capacity
• Enhances INSULIN production
• Promotes optimal cholesterol levels -supporting cardiovascular health

And the list goes on . . .

Vitamin D Functions

Vitamin D Health Benefits

Nearly every cell in the body contains vitamin D receptors.

Meaning the cells utilize vitamin D

Vitamin D receptors

Body's dietary vitamin D journey

• Vitamins D2 and D3 from dietary sources are packaged in chylomicrons and transported via the lymphatic system into venous circulation;
• Enzymes in the body convert both D2 and D3 vitamins into CALCIDIOL 25(OH)D (its circulating D form), and then the kidneys (and also the cells to some degree) convert this to CALCITRIOL 1,25(OH)₂D (its active form)

Forms of Vitamin D made in the Body

• Availability and conversion of vitamin D to its active form depends on several factors.   Including skin color and having a sufficiency of dietary fats

Factors Affecting D3 Availablility and Conversion in the Body

References

http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/

http://www.westonaprice.org/basicnutrition/vitamindmiracle.html

http://sunlightandvitamind.com/samples.htm Naked at Noon Krispin Sullivan