From the Guidelines
For a vitamin D level of 13.6 ng/mL, I strongly recommend taking vitamin D3 supplements at a dose of 50,000 IU 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 fact that a level of 13.6 ng/mL is considered deficient, and the goal is to bring the serum 25(OH) D levels to 30 ng/ml (75 nmol/L) or higher for optimal bone health. Some key points to consider when supplementing with vitamin D include:
- Vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) as it is more effective in raising 25(OH) D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed 1.
- The risk of vitamin D toxicity (hypercalcemia, hyperphosphatemia, and activation of bone resorption) 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.
- It is essential to recheck the serum 25(OH) D level after 8 weeks of supplementation to determine the need for continued supplementation and to adjust the dose accordingly.
- In addition to supplementation, increasing natural vitamin D sources by getting 15-30 minutes of sunlight exposure several times weekly and consuming vitamin D-rich foods like fatty fish, egg yolks, and fortified dairy products can also help improve vitamin D levels.
From the Research
Vitamin D Supplementation
- The optimal level of vitamin D is a subject of ongoing research, with most guidelines recommending serum 25OHD concentrations of >50 nmol/l for optimal bone health in older adults 2.
- For individuals with a vitamin D level of 13.6 nmol/l, supplementation is likely necessary to prevent and cure nutritional rickets in infants and children, as well as to correct severe vitamin D deficiency 2.
- However, the causal link between vitamin D and many extra-skeletal outcomes remains unclear, and supplementation of vitamin D-replete individuals does not provide demonstrable health benefits 2.
Safety of High-Dose Vitamin D Supplementation
- High-dose vitamin D supplementation (up to 10,000 IU/day) has been found to be safe and well-tolerated in healthy adults, with no significant differences in adverse events between treatment arms 3.
- However, hypercalciuria (elevated calcium levels in the urine) occurred more frequently with higher doses, and mild hypercalcemia (elevated calcium levels in the blood) occurred in 4% of participants taking 10,000 IU/day 3.
- The Tolerable Upper Intake Level (UL) for vitamin D is currently set at 50 microg (2000 IU), but some studies suggest that this level may be too restrictive and that higher doses may be safe and effective 4.
Health Benefits of Vitamin D Supplementation
- Vitamin D supplementation has been found to have variable effects on disease-specific and patient-oriented outcomes, suggesting a correlation but not a causal relationship between low vitamin D levels and disease pathogenicity 5.
- Emerging evidence suggests that vitamin D supplementation may reduce the risk of falls, COVID-19 severity, and mechanical ventilation, as well as improve symptoms in patients with atopic dermatitis and major depression 5.
- However, vitamin D supplementation does not seem to have an effect on the treatment of hypertension, cancer prevention, or improved cognition 5.