Vitamin D Supplementation: An Update

Christine Gonzalez, PharmD, CHHC

US Pharmacist

Abstract and Introduction

Introduction

An estimated 1 billion people worldwide, across all ethnicities and age groups, have a vitamin D deficiency.^[1–3] This is mostly attributable to people getting less sun exposure because of climate, lifestyle, and concerns about skin cancer. The 1997 Dietary Reference Intake (DRI) values for vitamin D, initially established to prevent rickets and osteomalacia, are considered too low by many experts.^[4] DRI values are 200 IU for infants, children, adults up to age 50 years, and pregnant and lactating women; 400 IU for adults aged 50 to 70 years; and 600 IU for adults older than 70 years. Current studies suggest that we may need more vitamin D than presently recommended to prevent chronic disease. Emerging research supports the possible role of vitamin D in protecting against cancer, heart disease, fractures and falls, autoimmune diseases, influenza, type 2 diabetes, and depression. Many health care providers have increased their recommendations for vitamin D supplementation to at least 1,000 IU.^[5] As a result, more patients are asking their pharmacists about supplementing with vitamin D.

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Cite this: Vitamin D Supplementation: An Update - Medscape - Oct 01, 2010.

Abstract and Introduction
Pharmacology
Deficiency, Blood Concentrations, and Toxicity
Disease Prevention
Dosing
Drug Interactions
Future Research
Conclusion
References

Table 1. Forms of Vitamin D
Cholecalciferol (vitamin D₃) Naturally occurring form of vitamin D; made by the skin upon sun exposure; found in foods and most supplements
Calcidiol (25-hydroxyvitamin D₃) Prehormone made directly from cholecalciferol in the liver; low biologic activity, but major form circulating in the bloodstream; concentrations measured by typical blood test for vitamin D deficiency
Calcitriol (1,25-dihydroxyvitamin D₃) Activated form made from calcidiol in the kidneys and tissues; the most potent steroid hormone in the body
Ergocalciferol (vitamin D₂) Made in the laboratory by radiating fungus; not naturally occurring in the body; used in prescription vitamin D (Drisdol), available in 50,000-IU capsules

Table 2. Dosing and Blood Concentrations
Dosage	Expected Increase in Blood Concentration
100 IU	1 ng/mL
200 IU	2 ng/mL
400 IU	4 ng/mL
800 IU	8 ng/mL
1,000 IU	10 ng/mL
2,000 IU	20 ng/mL

Source: Reference 30.

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Vitamin D Supplementation: An Update

Abstract and Introduction

Introduction

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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