From the Guidelines
For a vitamin D level of 14 ng/mL, I strongly recommend taking 50,000 IU of vitamin D2 or D3 once weekly for 8 weeks, followed by a recheck of the serum 25(OH) D level, with subsequent dosing based on the results, as suggested by the NCCN task force report 1. This approach is based on the current expert opinion that 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 for bone health, as stated in the NCCN task force report 1. Some key points to consider when supplementing with vitamin D include:
- The two forms of vitamin D available in supplements: D2 (ergocalciferol) and D3 (cholecalciferol), with vitamin D3 potentially being more effective in raising 25(OH) D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed 1.
- The importance of monitoring serum 25(OH) D levels to avoid toxicity, which is uncommon but may occur with daily doses of more than 50,000 IU per day that produce 25(OH) D levels larger than 150 ng/mL 1.
- The recommended daily intake of 800 to 1000 IU of vitamin D for adults older than age 50, and for younger patients at risk for cancer treatment–associated bone loss, as suggested by the NCCN Bone Health in Cancer Care Task Force 1.
From the Research
Vitamin D Supplement Dose for Vitamin D Level of 14
- The ideal vitamin D dosage to correct a deficiency and maintain optimal levels is still unclear 2.
- A study found that a maintenance dose of 2,000 IU of vitamin D3 per day was not enough to keep 25(OH)D levels above 30 ng/mL in patients who were initially vitamin D deficient 2.
- For patients with a vitamin D level of 14 ng/mL, a higher dose may be necessary to correct the deficiency.
- One study suggests that daily doses of 7,000 IU or intermittent doses of 30,000 IU/week may be effective in obtaining and maintaining 25(OH)D concentrations of at least 30 ng/mL in patients at high risk of vitamin D deficiency 3.
- Another study recommends that patients with severe vitamin D deficiency (serum 25-hydroxyvitamin D concentration <30 nmol/l) should be corrected, and most guidelines recommend serum 25OHD concentrations of >50 nmol/l for optimal bone health in older adults 4.
- In the absence of 25(OH)D level assessment, moderate vitamin D doses (e.g., 4,000 IU/day for adults) may be advised, with 25-OH-D levels checked later 5.
Considerations for Vitamin D Supplementation
- Magnesium is essential for the activation of vitamin D, and deficiency in either nutrient can be associated with various disorders 6.
- The health effects of vitamin D supplementation are still being studied, and while it can prevent and cure nutritional rickets, its extra-skeletal benefits are unclear 4.
- Vitamin D supplementation of vitamin D-replete adults does not provide demonstrable health benefits, but correcting severe vitamin D deficiency is still recommended 4.