From the Guidelines
If your vitamin D level is 17.6 ng/mL, you should take a vitamin D supplement of 2,000-4,000 IU daily, as recommended by the most recent and highest quality study 1. For faster correction, your healthcare provider might recommend a higher loading dose of 50,000 IU weekly for 8-12 weeks, followed by a maintenance dose of 1,000-2,000 IU daily. Some key points to consider when supplementing with vitamin D include:
- Taking vitamin D supplements with food containing some fat to improve absorption
- The specific dosage depends on factors like your age, weight, sun exposure, and other health conditions
- Vitamin D is essential for calcium absorption, bone health, immune function, and mood regulation
- After supplementing for 3 months, recheck your levels to ensure they're improving and adjust your dosage if needed
- Most people need ongoing supplementation to maintain healthy levels, especially those with limited sun exposure or certain health conditions that affect vitamin D metabolism It's also important to note that vitamin D toxicity 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, as stated in 1. Additionally, current expert opinion on supplementation for adults older than age 50 is 1200 mg of calcium (from all sources) and 800 to 1000 IU of vitamin D daily, as recommended in 1. However, many patients need more than the recommended amount and should be repleted based on serum 25(OH) D level, as suggested in 1. In terms of the type of vitamin D supplement, vitamin D3 (cholecalciferol) could be more effective in raising 25(OH) D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed, as compared to vitamin D2 (ergocalciferol), as stated in 1. Overall, it's essential to consult with your healthcare provider to determine the best course of treatment for your specific situation, taking into account your individual needs and health status, as well as the most recent and highest quality evidence, such as that presented in 1.
From the Research
Vitamin D Supplement Dosing
- The optimal dosing for vitamin D supplements is not clearly established, and the required amount may vary depending on individual factors such as skin exposure to sunlight, geographical location, and dietary intake 2.
- A study from 2016 found that long-term vitamin D supplementation resulted in increased risks of hypercalcemia and hypercalciuria, but did not increase the risk of kidney stones 3.
- Another study from 2021 found that vitamin D supplementation in adults with chronic liver diseases may increase or reduce all-cause mortality, liver-related mortality, serious adverse events, or non-serious adverse events, but the evidence is very uncertain due to the high risk of bias and insufficient power of the included trials 4.
- A review of randomized controlled trials and meta-analyses found that vitamin D supplementation has 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.
- A systematic review and meta-analyses of trials investigating the response to vitamin D supplementation in patients with chronic kidney disease found that the effect of vitamin D supplementation was inconsistent between studies, but calcifediol and analogues consistently suppressed parathyroid hormone (PTH) 6.
Considerations for Vitamin D Supplement Dosing
- The dose and duration of vitamin D supplementation may not be directly related to the risk of hypercalcemia, hypercalciuria, or kidney stones 3.
- Baseline vitamin D status, vitamin D dose, and duration of supplementation may not modify the effect of vitamin D supplementation on risk of hypercalcemia, hypercalciuria, or kidney stones 3.
- The form of vitamin D used (e.g. vitamin D3, vitamin D2, calcifediol, calcitriol) may affect the response to supplementation, with calcifediol and analogues consistently suppressing PTH in patients with chronic kidney disease 6.
- Individual factors such as age, sex, and comorbidities may influence the response to vitamin D supplementation and should be considered when determining the optimal dose and duration of supplementation.