From the Guidelines
Your vitamin D level of 11.5 ng/mL is significantly low despite taking 50,000 IU twice weekly, indicating inadequate absorption or other factors affecting your vitamin D status. I recommend continuing your current dose of 50,000 IU twice weekly for another 8-12 weeks, then retesting your levels, as suggested by the NCCN task force report 1. Additionally, ensure you're taking the supplement with a meal containing some fat to improve absorption, as vitamin D is fat-soluble. Consider discussing with your healthcare provider about potential causes for poor response, such as malabsorption disorders, kidney or liver disease, or medication interactions, as these conditions may affect vitamin D levels 1. They may want to check your calcium levels and parathyroid hormone as well. Your goal should be to reach a vitamin D level of at least 30 ng/mL, which is considered sufficient for bone health and overall wellbeing, according to the NCCN task force report 1. If your levels don't improve after continued high-dose supplementation, your provider might recommend further evaluation or alternative supplementation strategies, such as switching to vitamin D3, which may be more effective in raising 25(OH)D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed 1.
Key considerations for your treatment plan include:
- Continuing high-dose supplementation for an extended period to assess response
- Evaluating for potential causes of poor response, such as malabsorption or medication interactions
- Monitoring calcium and parathy hormone levels to assess overall bone health
- Considering alternative supplementation strategies, such as switching to vitamin D3, if levels do not improve with continued high-dose supplementation.
From the Research
Vitamin D Levels and Supplementation
- A vitamin D level of 11.5 ng/mL is considered deficient, as the normal serum 25-hydroxyvitamin D [25(OH)D] level is around 30 ng/mL 2.
- The optimal range for vitamin D levels is between 30 and 60 ng/mL 2.
- Taking 50,000 units of ergocalciferol (Vitamin D2) twice a week is a common replenishment therapy for vitamin D deficiency 3.
Effects of Vitamin D Supplementation
- Vitamin D supplementation can increase serum 25-hydroxyvitamin D levels, with one study showing an increase from 6.1 ng/mL to 47.4 ng/mL after treatment with sublingual vitamin D2 4.
- Another study found that vitamin D levels increased from 13.2 ± 4.0 to 42.8 ± 9.6 ng/mL after 2 months of supplementation with 50,000 units per week 5.
- However, incorrect dosing can lead to vitamin D toxicity, as seen in a case where a patient was given 50,000 units daily instead of weekly, resulting in a level of 100 ng/mL 3.
Target Vitamin D Levels
- Some studies suggest that increasing vitamin D levels to 50 ng/mL may be beneficial for overall health, with potential reductions in the risk of cancer and cardiovascular diseases 6.
- However, the Institute of Medicine (IOM) recommends a minimum serum level of 20 ng/mL, while most clinicians consider 30 ng/mL as the minimum necessary for good health 2.