For most people, supplementing with vitamin D is a safe and healthy practice. Getting too much vitamin D is rare and hard to achieve, usually requiring you to take a supplement of much more than 10,000 IU a day for several months. When you get too much vitamin D, you’re at risk of a condition called hypercalcemia, where you have too much calcium in your blood.
There are some health conditions, however, where you are at risk for hypercalcemia, no matter if you’re getting too much vitamin D, just the right amount of vitamin D or even not enough vitamin D. These conditions are termed “hypersensitive” to vitamin D, or these conditions have “hypersensitivity” to vitamin D. This means that people with these conditions should be careful when supplementing with vitamin D, because they are at greater risk of getting hypercalcemia.
These “hypersensitive” conditions are rare and diagnosed by a doctor, usual due to symptoms that are not related to hypercalcemia. For example, someone with sarcoidosis may be diagnosed after having some respiratory symptoms, not because they have symptoms of hypercalcemia. In fact, people with these conditions may never get hypercalcemia in their lifetime, but still require caution when supplementing with vitamin D.
If you have a condition “hypersensitive” to vitamin D, speak to your doctor if it is okay to take vitamin D. The conditions are:
Granulomatous diseases mean diseases that involve granulomas. A granuloma is a clump of cells involved in your immune system, a clump of cells that shouldn’t necessarily be there.
In some granulomatous diseases, your body can have a hard time controlling how much vitamin D it’s using and have a hard time controlling how much calcium it keeps in the blood. Therefore it’s important to work with a doctor when considering supplementing.
Granulomatous diseases are rare and not all are hypersensitive to vitamin D. In fact, even in some conditions that are hypersensitive to vitamin D, like sarcoidosis, it can still be safe to take vitamin D under a doctor’s care. These are common granulomatous diseases, some of which may be hypersensitive to vitamin D:
For people with sarcoidosis, about 10% develop hypercalcemia. About 50% of sarcoidosis patients develop hypercalcuria, which means more calcium than usual in your urine.
If you have sarcoidosis, make sure you work with your doctor before supplementing with vitamin D. Your doctor may wish to keep a careful eye on your calcium levels, and whether it is safe for you to take vitamin D.
For most people who get tuberculosis, they never get hypercalcemia. Studies that have measured the amount of calcium in the blood of people with tuberculosis show that anywhere from 0% to 28% get high blood calcium. Therefore, it is not well-known exactly how many people with tuberculosis get hypercalcemia. Doctors and scientists, however, think that it is rare and mild.
While it is probably safe to take vitamin D and may even play a role in the treatment of the condition, it’s important to work with your doctor and ask them about taking vitamin D. Your doctor may wish to keep a careful eye on your calcium levels, and advise whether it is safe for you to take vitamin D.
Other granulomatous diseases
Hypercalcemia in other granulomatous disorders is rare. These conditions include:
- cat-scratch disease
- granuloma annulare
If you have one of these conditions, ask your doctor about taking vitamin D. While hypercalcemia is rare in these conditions, your doctor may wish to keep a careful eye on your calcium levels and can let you know whether it is safe for you to take vitamin D. This should not discourage you from taking vitamin D, but encourage you to work with your doctor before doing so.
Lymphoma is a type of blood cancer. It makes up about 5% of all cancers.
Some studies report that 5% to 15% of patients with Hodgkin’s disease and non-Hodgkin’s lymphoma develop hypercalcemia. In one rare form of lymphoma – human T-cell leukemia virus type 1 – the risk of getting hypercalcemia may be even higher.
If you have lymphoma, ask your doctor about taking vitamin D. While hypercalcemia is rare in lymphoma, your doctor may wish to keep a careful eye on your calcium levels and let you know if it’s safe to take vitamin D. This should not discourage you from taking vitamin D, but encourage you to work with your doctor before doing so.
- Cusano NE, Thys-Jacobs S and Bilezikian JP. “Hypercalcemia Due to Vitamin D Toxicity.” In Vitamin D, Third Edition, by Feldman D, Pike JW and Adams JS. Elsevier Academic Press, 2011.