Sources of VITAMIN D

Prefer to obtain VITAMIN D from Sun and Food

Vitamin D from Supplements / Fortified Foods

D2 vs. D3. The two manufactured forms typically used to fortify food, such as milk, orange juice, bread and cereals, and used in vitamin supplements are:

• VITAMIN D3 (cholecalciferol). Typically made by irradiating lanolin from sheep's wool with ultra-violet light.

• VITAMIN D2 (ergocalciferol). Synthesized in a lab setting, usually by irradiating ergosterol (plant D2 precursor) extracted from yeast.

Studies conclude that VITAMIN D3 is considerably more potent than D2 (conservatively stated at 4 times more potent). In one particular study, although both D2 and D3 initially produced a similar rise in blood CALCIDIOL, after 3 days it then fell rapidly to baseline within 14 days, while D3 treated people continued to rise to a peak by 14 days, and then stayed high.

Armas LA et al, VITAMIN D2 is much less effective than VITAMIN D3 in humans. J Clin Endocrinol Metab 2004;89:5387-91] Abstract/FREE Full Text

It is suggested that this reflects the different affinities of D2 and D3 for the VITAMIN D binding protein. Also, D2 is broken down more rapidly than D3, and has a shorter shelf-life. One study estimated D2 at 20-40% as efficient as D3 at raising blood CALCIDIOL levels.

Trang HM, Cole DE, Rubin LA, Pierratos A, Siu S, Vieth R: Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2. Am J Clin Nutr 1998, 68:854-858. PubMedAbstract | PublisherFullText

Since the drug companies have a license for the use of the patented D2 form of D, expect to find that form in prescription supplements.

Daily Supplemental Dosages of VITAMIN D3

(VITAMIN D3 is preferred to D2)

As mentioned above, due to many factors, VITAMIN D Dosage is highly individual and the only way to know for sure if you are getting the right amount is to test your blood 25(OH)D level

Age	Dosage
Under 5	35 IU/#/day
Age 5-10	2500 IU
Age 18-30	5000 IU
Pregnant Women	5000 IU

( 1 µg vit. D = 40 IU )

The VITAMIN D council recommends ~ 4000 IU from dietary intake in the absence of UV-B light

- D3 Supplementation increases CALCIDIOL blood level - increasing D3 intake increases the liver's CALCIDIOLproduction, boosting the CALCIDIOL blood level. The kidneys and other body cells must produce CALCITRIOL (the active form of VITAMIN D) from CALCIDIOL. Blood CALCIDIOLlevels do not plateau until after about 3-4 months of consistent supplementation. Vieth R, et al, 2001.

- Under stress or treating disease condition, ensure maximize dosage

- Because VITAMIN D is fat-soluble, it is better utilized when taken with fat-containing meals

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