What's the D-eal with Vitamin D?
By Lacy Ternes, PharmD
Low vitamin D levels or "vitamin D deficiency" is defined as a total vitamin D level less than 20 ng/mL. This is very common after transplantation. Why is that? In an effort to prevent skin cancer, transplant recipients are advised to avoid or protect themselves from the sun – the body's major source of vitamin D. This leaves transplant recipients at risk for low levels of vitamin D because very few foods naturally contain vitamin D. Additionally, some medications taken after transplantation, such as prednisone, can reduce vitamin D levels in your body. It is strongly encouraged that all transplant recipients are screened for vitamin D deficiency. Although each transplant center is unique, if you have not had your total vitamin D level checked, you are encouraged to talk to your healthcare provider(s).
What are the consequences of Vitamin D deficiency?
Vitamin D deficiency can impact the health of your bones by leading to abnormalities in calcium, phosphorus, and bone metabolism. Muscle weakness may also occur if you are vitamin D deficient. The combination of reduced bone health and muscle weakness can increase your risk of falling and breaking bones.
What products are available for Vitamin D deficiency?
Vitamin D is available as both prescription and over-the-counter products. The prescription products are only available as vitamin D2, also known as ergocalciferol. Over-the-counter (OTC) products may be available as either vitamin D3, also known as cholecalciferol, or vitamin D2. The table below is a general list of available products and their corresponding vitamin D content. The type of product or "source" that you take is not as important as ensuring that you are taking an amount sufficient to achieve your goal total vitamin D level, which takes into account both vitamin D2 and vitamin D3.
**If you are taking a combination product of calcium plus vitamin D, don't forget to include the amount of vitamin D in your combined product along with your stand-alone vitamin D supplement for your total daily vitamin D intake.**
Vitamin D products
| Vitamin D Source | Vitamin D content |
| Prescription products available in the United States | |
| Vitamin D2 (ergocalciferol) | 50,000 IU per capsule |
| Drisdol (vitamin D2) liquid | 8,000 IU per milliliter |
| Supplemental Sources | |
| Multivitamin | 400, 500, or 1,000 IU vitamin D2 or vitamin D3 |
| Vitamin D3 | 400, 800, 1000, 2000, 5000, 10,000, or 50,000 IU |
How should you take Vitamin D?
Vitamin D can be taken on an empty stomach or with a meal. How frequently it is taken will be determined on your needs to achieve and maintain your goal vitamin D level.
Achieving your goal Vitamin D level:
A total vitamin D level greater than 30 ng/mL is often considered an appropriate goal; however, this number may vary depending on your individual needs and should be discussed with your healthcare provider(s). To treat vitamin D deficiency there are a variety of treatment regimens. Adults are commonly prescribed ergocalciferol 50,000 IU to be taken once a week for 8 weeks, followed by a re-check of their total vitamin D level. Once you achieve your goal level using the prescribed ergocalciferol often you will be advised to take an OTC product to maintain adequate vitamin D levels. The amount of vitamin D you take in an OTC product will depend on your needs, but commonly is in the range of 1000-2000 IU per day. After achieving your vitamin D goal, the frequency by which you will need to get your vitamin D levels re-checked will vary based on your healthcare provider. Obtaining a yearly level is common.
What are the benefits and safety issues associated with Vitamin D?
For adults, the benefits of vitamin D levels within the target range include the maintenance of healthy bones and reducing your chance of falling or braking bones. Although taking vitamin D is considered safe, how much you take should be determined based on your individual needs and the recommendations of your healthcare provider. Vitamin D may cause some people to develop high calcium levels in the blood and/or urine and should be monitored. Before you start a vitamin D supplement, talk with your healthcare provider to make sure vitamin D is safe and beneficial for you.
References:
- J Clin Endocrinol Metab, 2011; 96(7): 1911-1930
- Curr Opin Clin Nutr MetabCare, 2012;15:567-579
- Am J Kidney Dis, 2013;61(2):310-325
- Kidney Disease: Improving Global Outcomes. Transplant Work Group. KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant. 2009;9(Suppl 3):S1-S157