The Importance of Vitamin D.

Authored by: Harlan L. South, M.D., F.A.C.P.

   Vitamin D is an essential part of our overall daily health. Lack of vitamin D has been linked to a large number of medical diseases including osteoporosis, heart disease, and diabetes. More than 50% of all American women and 40% of all American men are considered to be deficient in vitamin D. The elderly are especially prone to this deficiency because they are homebound and often lack exposure to sunlight which is needed to activate the Vitamin D we have ingested.

   The general daily recommendation for vitamin D is 800 IU. Primary natural food sources of vitamin D include fish, especially wild salmon (600-1000 IU), mackerel, sardine, or tuna fish (200-300 IU). Fortified food such as milk, orange juice, yogurt, or breakfast cereal only provides 100 IU of daily vitamin D per serving. In our bodies, vitamin D is changed to its active form when skin is exposed to sunlight. Total body sun exposure for 15 minutes easily converts 10,000 IU of vitamin D. Artificial tanning also can help to activate vitamin D. However, sunscreen with an SPF of 8 can reduce the activation of vitamin D by 98%.

   Recent scientific evidence has revealed that vitamin D plays an important role in preventing many major medical diseases. For example, Osteoporosis in the elderly causes bone fractures in 75% of women and 50% men over the age of 65 years old. One study concluded that 800 IU of vitamin D and 1000 mg of calcium can reduce hip fractures by 43% and other fractures by 32% among postmenopausal women. Another study showed that patients with adequate levels of vitamin D have about one third the risk of developing diabetes. Patients with low levels of vitamin D have a higher risk of peripheral disease, stroke, and heart disease especially heart failure. Vitamin D can decrease hypertension by suppressing the renin-angiotensin system in the kidney. Other research studies have confirmed that vitamin D is important in reducing the risks of colon, prostate, and breast cancer.

   Vitamin D deficiency is defined as a level below 20ng/mL and it is treated with a prescription strength vitamin D2, which is a different form of vitamin D. The typical prescribed dose is 50,000 IU once a week. Vitamin D insufficiency is defined as a level between 20-32ng/mL and it is treated with an over the counter prescription vitamin D3. The typical recommended dose is 2000 IU per day. Patients with low levels of vitamin D should have their levels rechecked at least every 6 months after a therapeutic level of supplementation has been reached.

   In conclusion, vitamin D is an important vitamin that impacts many systems in the body. Vitamin D screenings are an important part of each patient’s annual physical exam. If you have further questions regarding your vitamin D levels or your overall health, we encourage you to schedule an appointment with your healthcare provider.