From the Guidelines
For a patient with a Vitamin D level of 35 ng/mL, the starting dose for Vitamin D supplements should be 800-1000 IU daily, as this level is considered adequate for bone health and supplementation is primarily for maintenance. According to the NCCN task force report 1, vitamin D should ideally be supplemented in amounts sufficient to bring serum 25(OH) D levels to 30 ng/ml (75 nmol/L) or higher, and for patients with levels between 20 and 30 ng/mL, an alternative is adding 1000 IU over the counter vitamin D2 or D3 per day to the patient's current intake. Some key points to consider when supplementing with Vitamin D include:
- Over-the-counter vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) because it raises blood levels more effectively and maintains them longer 1.
- The supplement should be taken with food containing some fat to improve absorption, as vitamin D is fat-soluble.
- After 3-6 months of supplementation, consider retesting the vitamin D level to ensure it's in the optimal range.
- Factors like limited sun exposure, darker skin, obesity, or certain medications may increase vitamin D needs, potentially requiring higher doses.
- If the patient has specific health conditions like kidney disease or takes medications that interact with vitamin D, they should consult their healthcare provider before starting supplements.
From the Research
Vitamin D Supplementation
- The patient's Vitamin D level is 35 ng/mL, which is considered optimal according to some studies 2.
- For patients with optimal Vitamin D levels, the decision to take Vitamin D supplements should be based on individual needs and health status 2.
- The US Endocrine Society's Clinical Practice Guideline suggests that 1500-2000 IU per day may be needed for adults to maintain 25(OH)D above the optimal level of 30 ng/ml 3.
- A daily dose of 2000 IU (50 µg) of Vitamin D3 may be considered a simple, effective, and safe dosage to prevent and treat Vitamin D deficiency in the adult general population 4.
- However, one study found that a maintenance dose of 2000 IU of Vitamin D3 per day was not enough to keep 25(OH)D levels above 30 ng/mL in patients who had previously been treated for Vitamin D deficiency 5.
Dosage Recommendations
- The US Institute of Medicine Recommended Dietary Allowance of Vitamin D is 600 IU per day for adults up to 70 years, and 800 IU per day for older adults 3.
- The US Endocrine Society's Clinical Practice Guideline suggests that 400-1000 IU per day may be needed for children aged less than 1 year, 600-1000 IU per day for children aged 1 year or more, and 1500-2000 IU per day for adults aged 19 years or more 3.
- One study suggests that an intake of 800 IU (20 microg) of Vitamin D3 per day for all adults may bring 97% of the population to a level of at least 50 nmol/l and about 50% up to 75 nmol/l 6.
- Another study estimates that 1600 to 2000 IU Vitamin D3 per day may successfully and safely achieve a serum 25(OH)D level of 75 nmol/l 6.