A recent analysis in the Annals of Internal Medicine lends further support to what medical experts have believed for years: vitamin D (the sun vitamin) deficiencies increase the risk of bone fractures, especially in the elderly. The relationship between our intake of vitamin D and bone health has been a much debated topic in nutrition circles, with its deficiency being linked to hip fractures as well as osteoporosis.

Vitamin D is a fat soluble vitamin that is actually produced by the body when it is exposed to sunlight, specifically ultraviolet B radiation. Because of valid concerns over skin cancer, however, limited sun exposure (including use of sunscreens) as well as the fact that vitamin D is absent in many foods can result in our bodies not getting enough, and that can lead to adverse health consequences.

After all, it is an important nutrient for the health of our immunity as well as neuromuscular development and the reduction of inflammation. It has also been linked to a reduced risk for breast, colon, and ovarian cancer. But perhaps one of its most significant roles involves the health or our bones.

Vitamin D is used by the body to maintain adequate levels of calcium in our blood as well as aid in its absorption (thus strengthening our bones). It is also needed by skeletal cells (osteoblasts and osteoclasts) for bone growth and restructuring. When deficiencies occur, bones can become brittle and weakened, so vitamin D in conjunction with calcium are recommended to protect older adults from osteoporosis.

In the review in question, doctors examined a dozen clinical trials in over 42,000 adults average age of 78 and found that when patients took a minimum of 400 IU (international units), or 10 micrograms of vitamin D per day, there was a 20% reduction in the risk of non-vertebral fractures in their bones and an 18% decrease in the risk of hip fractures.  400 IU seemed to be the critical dosage threshold, with amounts below that not displaying the same benefit. Some experts felt that the optimal effect might occur when vitamin D consumption began earlier and over a greater period of time.

Interestingly, in an article in the same edition of the journal, doctors have determined that Americans have insufficient levels vitamin D in their bodies, and that level has been declining over a period of sixteen years. Current dietary guidelines recommend that a twenty-five year old adult consume 200 IU, or 5 micrograms, of vitamin D per day. This may best be achieved by way of supplements or fortified foods. Certain fish and fish oils are also good sources.

However, dietary guidelines vary according to age and gender, and it is important to note that it is possible to take too much vitamin D (i.e., overdose) because it accumulates in the body. So before embarking on a vitamin D consumption spree, consult your physician and check out the dietary supplement fact sheet on vitamin D provided by the National Institutes of Health, which lists dosage recommendations as well as which foods to eat.