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Vitamin D Deficiency

Vitamin D deficiency is becoming an increasingly diagnosed disease in all age groups. While one of the most significant risk factors for low Vitamin D is being older than 65, the lowest levels of Vitamin D are actually found in younger ages (18-30) with no risk factors at all. We typically obtain 90 percent of our Vitamin D from sunlight, so perhaps sunscreen and sun avoidance are contributing to this increased frequency, as well as a heightened awareness by doctors who are including Vitamin D levels in their health screening. The risk factors for having low Vitamin D include aging, dark skin, inadequate sunlight exposure, obesity, a non-active lifestyle, and certain medications.

Vitamin D has a very important role in skeletal development, muscular function, and nerve responses.  Many foods are now fortified with Vitamin D, such as cereal, orange juice, and milk. Other food sources include salmon, tuna, cod liver oil, and egg yolk. However, only about 10 percent of Vitamin D is obtained from food or dietary sources.

Vitamin D is a necessary factor for bone and mineral health. Unless there is activated Vitamin D, only 10 percent of calcium and a little over half of body phosphorus is absorbed.  Calcium plays a crucial role in maintaining our body integrity (bones), normal heart function, and nerve contraction and muscular function. When the body can't absorb calcium, it begins relying on the skeleton and disolves our existing bone for its mineral source. This of course leads to bone weakness, demineralization, and fractures.

What are the major manifestations of Vitamin D deficiency?  Muscle aches and muscle weakness are prominent.  There may be bone pain or discomfort felt mostly in the lower back and extremities. There is an increased risk of falls and impaired physical function, and the weakened body skeleton predisposes the bones to fractures.  A symmetrical bone pain across the lower back is also one of the more common presentations of a lack of Vitamin D.

As we age, more than four-fifths of hip fractures are caused by falling, and the mortality rate can be as high as one in five. The role of Vitamin D has been increasingly implicated in many other medical conditions. Low vitamin D levels are shown in newer studies as risk factors in high blood pressure, increased blood glucose levels, and cardiac disease. The Framingham Offspring Study implicated Vitamin D deficiency with significantly higher rates of cardiovascular events. Colon cancer and depression are two other diseases that appear to be linked in part to low Vitamin D levels.

As Vitamin D is a fat soluble vitamin, it may be stored and become toxic if given in overly high doses and can cause complications such as nausea, vomiting, headache, kidney stones, and pancreatitis.  For that reason, supplementation should be in recommended doses and followed with blood measurements to gauge the right amount. Most multivitamins contain 400 International units (IU) of Vitamin D, and further supplementation to 700-800 IU helps reduce the affects falls and fractures as we age. Children who don't get out in the sunlight much or whose milk and dietary intake is low can also benefit from supplementation. Mention checking your Vitamin D level to your physician during your next physical check-up. It could be a life-saver.

Authored by Dr. Bob Goldstone, M.D.
