It has long been known that we need vitamin D for bone health because the body needs the vitamin to absorb calcium. Levels of vitamin D in the human body are declining due to reduced sunlight exposure and lower intakes of the vitamin. The main food source of vitamin D is fortified milk, however most adults do not consume 32 ounces (4 cups) of milk daily.
The other main source of vitamin D is from the sun but with the advent of sunscreen the UV radiation necessary to generate vitamin D in the skin is blocked. In the winter, anyone who lives north of the latitude of Atlanta, Georgia USA cannot absorb enough sun to generate vitamin D production. Pollution and cloud cover also affect the amount of UV radiation that reaches the skin. African Americans have about half as much vitamin D in their blood as Caucasians, and people 65 and older have only about ¼ of vitamin D in their bodies when compared to people in their 20s. Many elderly have low levels of vitamin D in their blood because, as we age, the skin’s ability to produce vitamin D is diminished. Also, many elderly are institutionalized or housebound.
New research is suggesting that vitamin D may be good for more than bone health. Adequate vitamin D levels in the body are now being related to physical weakness in old age, depression, colon cancer, immune function, pneumonia and diabetes. Those experiencing bone or muscle pain might have osteomalacia, which is softening of the bones due to defective bone mineralization because of inadequate vitamin D. DEXA bone density tests, which reveal osteoporosis, do not differentiate between osteomalacia and osteoporosis. Vitamin D status is easily determined with a blood test.
Researchers are suggesting a daily vitamin D intake of at least 1,000 IU (International Units). It would be almost impossible to get this amount of vitamin D from foods. Most multivitamin supplements provide 400 IU per tablet. Do not take 2 multivitamins because then you will get too much of other minerals and vitamins. Many calcium supplements contain 400-500 IU’s per 600 mg of calcium so if 600 mg of calcium is consumed twice a day these supplements will provide 800-1,000 IU’s of vitamin D. If vitamin D supplements are taken they should be vitamin D3 (cholecalciferol) rather than Vitamin D2. Do not exceed 2,000 IU of vitamin D daily. This is the current upper limit set by the National Academy of Sciences.
