Overview

Why should someone supplement with vitamin D?
Many clinical trials have demonstrated the benefits of vitamin D to support bone strength and density:^†

• Supplementation with vitamin D at dosages of 700-800 IU daily or higher has been associated with a 23-26% improvement in bone health, especially for older adults.^†

Why use Vitamin D3 1000 IU?
It is convenient:

• Vitamin D3 provides an easy way to increase intake of cholecalciferol - the same form of vitamin D our bodies create naturally.

To support healthy bones:^†

• Healthy bones need vitamin D to properly use calcium and phosphorus.^† Vitamin D helps regulate calcium and phosphorus absorption through the intestines, reduces kidney excretion of calcium, and regulates the amount of calcium in the bones.^†

To support a healthy immune system and other health functions in the body:^†

• Vitamin D has been shown to enhance healthy cell replication and division, as well as influencing healthy glucose metabolism.^†

Directions

One tablet daily. May increase to one tablet twice daily, or as directed by your healthcare practitioner.

Pill Size

Interactions and Depletions

Technical Data

Description

Vitamin D-3 contains 1000 IU of vitamin D per tablet, in the form of cholecalciferol (D3). This form of vitamin D is from a natural source. Research has shown that cholecalciferol is more potent and has greater health benefits, especially for bone health, than ergocalciferol (D2).^{† 1}

• Natural source of vitamin D
• High dose level for greater support of bone density and immune function^†
• 1000 IU of vitamin D per tablet

Introduction

Vitamin D is considered to be both a vitamin and a prohormone. Because human skin cells can synthesize adequate vitamin D after exposure to UV-B rays from sunlight, it is sometimes called the “sunshine vitamin.” ² A precursor (7- dehydrocholesterol) of vitamin D can be converted by skin cells into cholecalciferol, or vitamin D3. Vitamin D3 is then converted in the kidneys and liver to 1,25-dihydroxyvitamin D3, or calcitriol, which is the principal active hormonal form of vitamin D.³ As a vitamin, vitamin D can also be absorbed from food.

How Does It Work?

The most well known benefit of vitamin D is its role in supporting bone health.^† Vitamin D helps regulate calcium and phosphorus absorption through the intestines, reduces kidney excretion of calcium, and regulates the amount of calcium in bones.^†4 This nutrient is critical for healthy skeletal development and bone mineralization.^†5 New research has focused on the ability of vitamin D to enhance healthy cell replication and division, as well as influencing healthy glucose metabolism.^{† 6,7}

The primary source of vitamin D is through exposure to sunlight. However, many Americans, particularly the elderly, are lacking in vitamin D. From 38-60% of elderly institutionalized adults have been found to have inadequate intake of vitamin D (depending on time of year tested).^8,9 This is believed to be due to both a failure to gain exposure to adequate amounts of sunlight (many elderly spend little time outdoors), and because the vitamin D synthesis process becomes less efficient with aging.¹⁰ Supplemental vitamin D intake is therefore especially important in older adults.^†2

Vitamin D and Immune Health^†
Many epidemiological studies have found vitamin D intake is associated with immune function.^† New research is clarifying how the hormonal form of vitamin D – 1,25-dihydroxyvitamin D – impacts the immune system.^† The first mechanism of action is through the regulation of cellular proliferation, differentiation, apoptosis, and angiogeneis.^{† 11,12} Many cells, including breast, brain, prostate, and colon tissue, as well as immune cells, have receptors which can be activated by 1,25-dihydroxyvitamin D.^†13 Cell studies have shown that vitamin D, in the form of cholecalciferol, supports normal prostate cell replication and division.^†14 Secondly, vitamin D is a potent immunomodulator, and has been shown to stimulate human macrophage cell activity.^†15

Vitamin D and Bone Health^†
Vitamin D influences bone density both through its facilitation of calcium absorption through the intestinal tract, and its affect on bone deposition and bone resorption.^† In women with low serum levels of vitamin D, increasing vitamin D intake has been shown to increase intestinal calcium absorption by up to 65%.^{† 16} In bone, vitamin D stimulates bone turnover, while exerting a protective effect on osteoblasts (bone building compounds).^{† 17}

The classic bone disease associated with vitamin D deficiency is rickets. Characterized by bowed legs, a bent spine, and weak, toneless muscles, rickets was thought to have been a disease of the past in the United States. However, a 2004 case review found 166 cases of children with rickets reported in the medical literature between 1986 and 2003.¹⁸

Many clinical trials have demonstrated the benefits of vitamin D to support bone strength and density.^† Supplementation with vitamin D at dosages of 700-800 IU daily or higher has been associated with a 23-26% improvement in bone health, especially for older adults.^†19 Experimental vitamin D (cholecalciferol) dosages have been as high as 100,000 IU (given as one 100,000 IU capsule taken 4 times a year) in trials documenting benefits for bone health.^†20

Cholecalciferol vs. Ergocalciferol
Vitamin D supplements generally provide this vitamin as either cholecalciferol (vitamin D3) or ergocalciferal (vitamin D2). Ergocalciferol is derived from plant or fungal sources. It is not produced in the body. Cholecalciferol is from animal sources and is the form synthesized by the body.⁸ Although ergocalciferol may be preferred by vegetarians, research has established that cholecalciferol is the more potent form of this vitamin.¹ Clinical trials have noted that cholecalciferol raises serum levels of vitamin D3 2-3 times higher than equivalent doses of ergocalciferol.^†1

Vitamin D intake and Dosage
As noted above, dosages given in clinical trials have been much higher than the current 200 IU daily Adequate Intake (adults) recommended by the Institutes of Medicine (IOM). The IOM has also set the no-observed-adverse-effect-level (NOAEL) at 2000 IU daily (based on the serum levels of vitamin D associated with hypercalcemia).²¹ As a comparison, the United Kingdom has published a guidance level of 1000 IU daily as the recommended intake.²²

Suboptimal levels of Vitamin D intake has been documented, especially among older adults. From 38-60% of elderly institutionalized adults have been found to be lacking in vitamin D intake (depending on time of year tested).^8,9 In a study of women living in Michigan, 67% were lacking in vitamin D, as indicated by a 25-hydroxyvitamin D (the hormonal form of vitamin D) level of less than 20 ng/mL. Non-Caucasians were 3 times more likely than Caucasians to have low vitamin D levels. Participants with total vitamin D intake < 400 IU/day from diet and supplements were 10 times more likely to have low vitamin D levels than others.²³ A study of pregnant women living in the northern United States found that 85% of black mothers had insufficient levels of vitamin D, while 47% of white mothers had insufficient levels.²⁴

Many experts disagree with the guidelines set by the IOM, and feel that the minimum recommended intake for Americans needs to be raised.^25,26 Although extremely high levels of vitamin D intake have been associated with hypercalcemia, toxicity of vitamin D has not been reported in dosages up to 10,000 IU daily.²⁷

Conclusion
Vitamin D-3 provides a convenient way to increase intake of cholecalciferol – the natural form of vitamin D – to promote a strong immune system, as well as healthy bones.^†

Recommendations

One tablet daily. May increase to two tablets daily or as directed by your healthcare practitioner.

Precautions

If pregnant, nursing, or taking prescription drugs, consult your healthcare practitioner prior to use.

How Is It Supplied?

• 06939;90 tablets

Storage Recommendations

Store at controlled room temperature, 59° to 86°F (15° – 30°C).

References

1. Houghton LA, Vieth R. The case against ergocalciferol (vitamin D2) as a vitamin supplement. Am J Clin Nutr. 2006;84(4):694-7.
2. Vitamins A, D, E and K. In: Wardlaw GM, Insel PM. Perspectives in Nutrition. 2nd ed. St. Louis, Missouri: Mosby; 1993: 358.
3. Holick MF. Vitamin D. In: Shils ME, ed. Modern Nutrition in Health and Disease. 9th ed. Baltimore, Maryland: Williams and Wilkins; 332.
4. Grant WB, Holick MF. Benefits and requirement of vitamin D for optimal health: a review. Altern Med Rev. 2005;10:94-111.
5. Vitamin D. In: PDR for Nutritional Supplements. Montvale, New Jersey: Medical Economics Company; 2001:498-503.
6. Masuda S. Promise of vitamin D analogues in the treatment of hyperproliferative conditions. Mol Cancer Ther. 2006;5(4):797-808.
7. Pittas AG, Dawson-Hughes B, Li T, et al. Vitamin D and calcium intake in relation to type 2 diabetes in women. Diabetes Care. 2006;29(3):650-6.
8. Liu BA, Gordon M, Labranche JM, Murray TM, Vieth R, Shear NH. Seasonal prevalence of vitamin D deficiency in institutionalized older adults. J Am Geriatr Soc. 1997;45(5):598-603.
9. Gloth FM, Gundberg CM, Hollis BW, Haddad JG, Tobin JD. Vitamin D deficiency in homebound elderly persons. JAMA. 1995;274(21):1683-6.
10. Vitamins A, D, E and K. In: Wardlaw GM, Insel PM. Perspectives in Nutrition. 2nd ed. St. Louis, Missouri: Mosby; 1993: 358.
11. Li H, Stampfer MJ, Hollis JB, et al. Prospective Study of Plasma Vitamin D Metabolites, Vitamin Receptor Polymorphisms, and Prostate Cancer. PLoS Med. 2007;4(3):e103.
12. Murillo G, Matusiak D, Benya RV, Mehta RG. Chemopreventive efficacy of 25-hydroxyvitamin D3 in colon cancer. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):763-7.
13. Pendás-Franco N, González-Sancho JM, Suárez Y, et al. Vitamin D regulates the phenotype of human breast cancer cells. Differentiation. 2007;75(3):193-207.
14. Tokar EJ, Webber MM. Cholecalciferol (vitamin D3) inhibits growth and invasion by up-regulating nuclear receptors and 25-hydroxylase (CYP27A1) in human prostate cancer cells. Clin Exp Metastasis. 2005;22(3):275-84.
15. Chandra G, Selvaraj P, Jawahar MS, Banurekha VV, Narayanan PR. Effect of vitamin D3 on phagocytic potential of macrophages with live Mycobacterium tuberculosis and lymphoproliferative response in pulmonary tuberculosis. J Clin Immunol. 2004;24(3):249-57.
16. Heaney RP, Dowell MS, Hale CA, Bendich A. Calcium absorption varies within the reference range for serum 25-hydroxyvitamin D. J Am Coll Nutr. 2003 Apr;22(2):142-6.
17. Montero-Odasso M, Duque G. Vitamin D in the aging musculoskeletal system: an authentic strength preserving hormone. Mol Aspects Med. 2005;26(3):203-19.
18. Weisberg P, Scanlon KS, Li R, Cogswell ME. Nutritional rickets among children in the United States: review of cases reported between 1986 and 2003. Am J Clin Nutr. 2004;80(6 Suppl):1697S-705S.
19. Izaks GJ. Fracture prevention with vitamin D supplementation: considering the inconsistent results. BMC Musculoskelet Disord. 2007;8:26.
20. Trivedi DP, Doll R, Khaw KT. Effect of four monthly oral vitamin D3 (cholecalciferol) supplementation on fractures and mortality in men and women living in the community: randomised double blind controlled trial. BMJ. 2003;326(7387):469
21. Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press. 250-287.
22. Vieth R. Critique of the considerations for establishing the tolerable upper intake level for vitamin D: critical need for revision upwards. J Nutr. 2006;136(4):1117-22.
23. Kakarala RR, Chandana SR, Harris SS, Kocharla LP, Dvorin E. Prevalence of vitamin D deficiency in uninsured women. J Gen Intern Med. 2007;22(8):1180-3.
24. Bodnar LM, Simhan HN, Powers RW, et al. High prevalence of vitamin D insufficiency in black and white pregnant women residing in the northern United States and their neonates. J Nutr. 2007 Feb;137(2):447-52.
25. Vieth R. Why the optimal requirement for Vitamin D3 is probably much higher than what is officially recommended for adults. J Steroid Biochem Mol Biol. 2004 May;89-90(1-5):575-9.
26. Viljakainen HT, Palssa A, Kärkkäinen M, Jakobsen J, Lamberg-Allardt C. How much vitamin D3 do the elderly need? J Am Coll Nutr. 2006;25(5):429-35.
27. Hathcock JN, Shao A, Vieth R, Heaney R. Risk assessment for vitamin D. Am J Clin Nutr. 2007;85(1):6-18.

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