Vitamin D supplements

There are many types of vitamin D preparations available for the treatment of vitamin D deficiency or insufficiency. The two commonly available forms of vitamin D supplements are ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). We suggest vitamin D3 when possible, rather than vitamin D2, because vitamin D3 is the naturally occurring form of the vitamin and it may raise vitamin D levels more effectively.

Dosing

The recommended dose of vitamin D depends upon the nature and severity of the vitamin D deficiency.

• In people who do not have problems absorbing vitamin D:
• In people whose 25OHD is <20 ng/mL (50 nmol/L), treatment usually includes 50,000 international units of vitamin D2 or D3 by mouth once or more per week for six to eight weeks, and then 800 to 1000 (or more) international units of vitamin D3 daily thereafter.
• In people whose 25OHD is 20 to 30 ng/mL (50 to 75 nmol/L), treatment usually includes 800 to 1000 international units of vitamin D3 by mouth daily, usually for a three month period. However, many individuals will need higher doses. The “ideal” dose of vitamin D is determined by testing the individual’s 25OHD level, and increasing the vitamin D dose if the level is not within normal limits. Once a normal level is achieved, continued therapy with 800 international units of vitamin D per day is usually recommended.
• In infants and children whose 25OHD is <20 ng/mL (50 nmol/L), treatment usually includes 1000 to 5000 international units of vitamin D2 by mouth per day (depending on the age of the child) for two to three months.

In people who have diseases or conditions that prevent them from absorbing vitamin D normally (eg, kidney or liver disease), the recommended dose of vitamin D will be determined on an individual basis.

In people whose vitamin D level is normal (>30 ng/mL [≥75 nmol/L]), a dose of 800 international units of vitamin D per day is usually recommended.

Monitoring

A blood test is recommended to monitor blood levels of 25OHD three months after beginning treatment. The dose of vitamin D may need to be adjusted based on these results.

Side effects

Side effects of vitamin D are uncommon unless the 25OHD level becomes very elevated (>100 ng/mL or 250 mmol/L) and the person is taking high dose calcium supplements. However, it is important to follow dosing instructions closely and to avoid taking multiple products that contain vitamin D (eg, multivitamin and vitamin D).

If 25OHD levels do become very elevated, complications such as high blood calcium levels or kidney stones can develop.