From the Guidelines
For individuals with limited sun exposure but without severe vitamin D deficiency, a daily supplement of 400-800 IU of vitamin D is recommended, as stated in the K/DOQI clinical practice guidelines 1. This dosage is based on the guidelines for the prevention of vitamin D deficiency, which suggest 400 IU for younger adults and 800 IU for individuals over 60 years. Some key points to consider when supplementing with vitamin D include:
- The recommended upper limit of vitamin D is 2,000 IU/day according to the Food and Nutrition Board, National Research Council, National Academy of Sciences 1.
- Dosage preparations of 10,000 IU of ergocalciferol have been given daily to patients with advanced CKD for periods longer than 1 year, with no evidence of vitamin D overload or renal toxicity 1.
- The safer vitamin D sterol may be ergocalciferol rather than cholecalciferol, although there are no controlled comparisons of cholecalciferol and ergocalciferol in humans 1. It's essential to note that individuals with limited sun exposure may require supplementation to maintain adequate vitamin D levels, which are crucial for calcium absorption, bone health, and immune function. When choosing a supplement, consider the following:
- Look for vitamin D supplements that are available over the counter, such as 400 IU capsules.
- Alternatively, prescription capsules containing 50,000 IU can be taken once a month to achieve the recommended daily allowance.
- It's also important to consult with a healthcare professional to determine the best course of treatment and to monitor vitamin D levels regularly.
From the Research
Recommended Vitamin D Dose
For individuals with limited sun exposure but without severe vitamin D deficiency, the recommended dose of vitamin D can vary.
- The Dietary Reference Intake (DRI) recommendation for persons up to 50 years is close to 5 microg, however, the amount of vitamin D needed to maintain a sufficient 25OHD level during winter is >12.5 microg 2.
- In the absence of adequate sun exposure, at least 800-1000 IU vitamin D3/d may be needed to achieve a circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL 3.
- Children and adults who do not receive adequate vitamin D from sun exposure need at least 1000 IU/d vitamin D 4.
Considerations for Vitamin D Supplementation
- Oral supplementation with 1,000 IU vitamin D3 daily significantly increased serum 25(OH)D levels in vitamin D-deficient participants after 3 mo, while sunlight exposure did not 5.
- Supplement use can increase mean intake to >12.5 microg but does not always reach those who need it most 2.
- Fortification and supplementation may be effective to achieve intakes of 12.5 microg vitamin D in some of the population, but for many achieving the amount needed in the absence of skin synthesis requires intakes above the current upper level for vitamin D of 50 microg 2.