Vitamin D Questions

What is vitamin D?

Vitamin D is a “fat soluble” vitamin that works with other vitamins, minerals and hormones to maintain normal blood levels of calcium and phosphorous. It increases the absorption of calcium from the intestines, promotes retention of calcium by the kidneys, and slows down the secretion of parathyroid hormone by the parathyroid glands.

How much vitamin D do I need?

The recommended daily intake of vitamin D varies according to age. The National Osteoporosis Foundation recommends 800-1000 International Units (IU) per day for adults. Some individuals may need more than this. If there is uncertainty that you are getting enough vitamin D, it may be helpful to measure the level of 25-hydroxyvitamin D in the blood. Many experts recommend that the blood level be kept in the range of about 30-50 ng/ml. This is a “desirable” level, which may be different than the “normal” level printed on the laboratory report.

What happens if I don’t get enough vitamin D?

Vitamin D deficiency can impair calcium absorption enough to cause osteoporosis, osteomalacia, or rickets, depending on age and the severity of deficiency. A condition called “secondary hyperparathyroidism,” which increases the rate of bone metabolism and causes loss of bone, often occurs. Vitamin D deficiency may also result in reduced muscle strength, increased risk of falling, and possibly increased risk of some types of cancer, such as breast, prostate, and colon cancer.

How common is Vitamin D deficiency?

Unfortunately, vitamin D deficiency is very common. It can occur in anyone, but those most likely to have it are the elderly; anyone with an intestinal malabsorption problem; anyone taking anticonvulsant medication; anyone who gets little exposure to the sun due to being indoors, using protective clothing or sunblock; those living in Northern latitudes; and those who never take vitamin supplements. Even in sunny New Mexico, vitamin D deficiency is common.

Can I get too much Vitamin D?

Yes. However, vitamin D toxicity is very rare compared to vitamin D deficiency. It has not been reported in anyone taking less than 10,000 IU per day.

How do I get Vitamin D?

In children, exposure to the sun with normal outdoor activities is usually sufficient. There are only a few natural food sources with high levels of vitamin D- primarily fish oils, such as cod liver oil, and oily saltwater fish, as cod, mackerel, and sardines packed in oil. All adults should consider taking a daily multivitamin containing vitamin D. Calcium that has vitamin D added is usually a good idea. Some individuals may need additional vitamin D supplements. Vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) both work well, although D3 might be a little better.