How much Vitamin D (D2: Ergocalciferol, and D3: Cholecalciferol) should I take daily?
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Daily Vitamin D Intake: Ergocalciferol (D2) and Cholecalciferol (D3)
Introduction to Vitamin D Supplementation
Vitamin D is essential for maintaining healthy bones and supporting immune function. It exists in two primary forms: ergocalciferol (D2) and cholecalciferol (D3). Both forms are used in supplements, but their efficacy and optimal dosing can vary.
Efficacy of Vitamin D2 vs. D3
Comparative Effectiveness
Research indicates that cholecalciferol (D3) is generally more effective than ergocalciferol (D2) in raising and maintaining serum 25-hydroxyvitamin D [25(OH)D] levels. A systematic review and meta-analysis found that D3 is superior in improving vitamin D status and reducing parathyroid hormone (PTH) levels across various dosages and demographics2. Another study confirmed that D3 increases total 25(OH)D more effectively than D2, which can even lead to a decrease in 25(OH)D3 levels when supplemented with D26.
Dosage and Administration
Different studies have explored various dosing regimens for both forms of vitamin D. For instance, a study involving older adults showed that both daily (1,600 IU) and monthly (50,000 IU) doses of D2 and D3 were effective, but D3 had a slight edge in increasing serum 25(OH)D levels1. Another study demonstrated that a high-dose regimen of D3 (50,000 IU twice weekly) was the most effective in rapidly achieving and maintaining adequate vitamin D levels3.
Recommended Daily Intake
General Recommendations
For most adults, a daily intake of 2,000 to 3,000 IU of D3 is effective in maintaining adequate vitamin D levels without causing toxicity3. This dosage is particularly recommended for individuals with low baseline vitamin D levels or those at risk of deficiency.
High-Dose Interventions
In cases of severe deficiency, higher doses may be necessary. A single large dose of 300,000 IU of D3 has been shown to significantly improve vitamin D status for up to three months4. However, doses above 500,000 IU should be used cautiously to avoid adverse effects4.
Special Populations
For individuals with obesity, higher doses of D3 may be required to achieve adequate serum 25(OH)D levels. A study on obese infertile men found that an initial bolus of 300,000 IU followed by daily supplementation of 1,400 IU was effective in reaching sufficient vitamin D levels10.
Safety and Tolerable Upper Intake Levels
The European Food Safety Authority (EFSA) has established a tolerable upper intake level (UL) of 100 µg (4,000 IU) per day for adults, including pregnant and lactating women, to prevent hypercalcemia and other adverse effects5. For children aged 1-10 years, the UL is set at 50 µg (2,000 IU) per day5.
Conclusion
Cholecalciferol (D3) is generally more effective than ergocalciferol (D2) in improving and maintaining vitamin D levels. For most adults, a daily intake of 2,000 to 3,000 IU of D3 is recommended. In cases of severe deficiency or for individuals with obesity, higher doses may be necessary, but should be administered with caution to avoid toxicity. Always consult with a healthcare provider before starting any new supplementation regimen.
Sources and full results
Most relevant research papers on this topic
Evaluation of ergocalciferol or cholecalciferol dosing, 1,600 IU daily or 50,000 IU monthly in older adults.
Cholecalciferol is slightly more effective than ergocalciferol in increasing serum 25(OH)D levels in older adults, with both showing significant between-individual response.
RCT
Very Rigorous Journal
Highly CitedRelative Efficacy of Vitamin D2 and Vitamin D3 in Improving Vitamin D Status: Systematic Review and Meta-Analysis
Cholecalciferol is more effective than ergocalciferol in improving vitamin D status and regulating PTH levels, regardless of participant demographics, dosage, and supplementation vehicle.
Meta-AnalysisVery Rigorous JournalA PROSPECTIVE STUDY OF COMMONLY UTILIZED REGIMENS OF VITAMIN D REPLACEMENT AND MAINTENANCE THERAPY IN ADULTS.
All four schedules of vitamin D replacement effectively achieved and maintained 25(OH)D levels above 30 ng/mL, with 50,000 IU D2 twice weekly providing the most rapid and highest mean levels.
RCTLarge, single-dose, oral vitamin D supplementation in adult populations: a systematic review.
A single vitamin D3 dose of 300,000 IU is most effective in improving vitamin D status and suppressing parathyroid hormone concentrations for up to 3 months.
Systematic ReviewHighly CitedScientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate
The EFSA Panel recommends a tolerable upper intake level of 100 g vitamin D equivalents/day for adults, 11-17 years, and 50 g for children aged 1-10 years, based on persistent hypercalciuria as a critical endpoint.
Literature ReviewBioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial.
Vitamin D3 increases total 25(OH)D concentration more than vitamin D2, while vitamin D2 supplementation leads to a decrease in 25(OH)D3, explaining the different effect on total 25(OH)D.
RCT
Rigorous JournalHighly CitedDifferential effects of vitamin D2 and D3 supplements on 25-hydroxyvitamin D level are dose, sex, and time dependent: a randomized controlled trial
Vitamin D2 supplements show higher 25(OH)D levels than D3 supplements, with a higher dose and sex-dependent effect on 25(OH)D levels.
RCTRigorous JournalShort and long-term variations in serum calciotropic hormones after a single very large dose of ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) in the elderly.
Cholecalciferol is nearly twice as potent as ergocalciferol in increasing serum 25(OH)D levels and modulating serum PTH in elderly female patients with vitamin D deficiency.
RCTRigorous JournalHighly CitedEffects of a 10-day course of a high dose calciferol versus a single mega dose of ergocalciferol in correcting vitamin D deficiency
The 10-day oral D3 regimen rapidly and effectively normalized 25(OH)D levels, potentially resulting in higher patient compliance.
Non-RCTRigorous JournalHigh-dose cholecalciferol supplementation to obese infertile men is sufficient to reach adequate vitamin D status
High-dose vitamin D3 supplementation is sufficient for obese infertile men with low vitamin D status to achieve adequate serum 25OHD levels.
RCT
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