Busy UW-Madison students do not always consider their health a top priority. But recent studies indicate students do not get enough vitamin D during the winter months, which could lead to health problems later on.
About 67 percent of the 200 UW-Madison students tested in a March 2004 study were deficient in vitamin D. The study was conducted by the UW Osteoporosis Research Center.
The average adult needs 800 to 2,000 units of vitamin D for proper health. One glass of milk contains 100 units of vitamin D3, one of the two main forms of vitamin D.
The vitamin's most vital role is to metabolize calcium into a form the body can use, according to Susan Nitzke, UW professor of nutritional sciences. A vitamin D deficiency can result in decreased calcium absorption, leading to diseases like osteoporosis, in which bones lose density and become more susceptible to fractures.
While a person can get vitamin D from food, there is a simpler way to get it-a person's skin produces vitamin D in the presence of direct sunlight, specifically its ultraviolet rays. Skin contains the vitamin's precursor, which UV light converts into vitamin D. Hence the vitamin is known as the sunshine vitamin.
Of course, winter months present a challenge as sunlight levels decrease. Northern cities like Madison do not receive sufficient sunlight during the winter, putting residents at risk of vitamin D deficiency, said Karen Hansen, assistant professor of medicine at UW-Madison. In order for people to produce enough vitamin D, they need to expose their skin to direct sunlight for at least 30 minutes, three to five times a week, Hansen said. But in winter, when students are bundled up and huddled indoors, they are not giving the sun's UV rays the opportunity to produce vitamin D.
Other impediments to vitamin D production are lotions that have a sun protection factor, or SPF, of 15 or higher. People with darker skin tones are also at risk.
\There have been studies showing that if people have pigment in their skin, they need from three- to six-fold longer sun exposure to make vitamin D in their skin,"" Hansen said.
Since Wisconsin winters do not allow for too much vitamin D production, Elliott suggests that college students supplement their diet with vitamin D. Common sources of vitamin D3 are fatty fish, such as tuna and salmon, as well as fortified milk and cereals.
Hansen suggests concerned students get their vitamin D levels checked by a doctor. The test is simple-it measures the level of vitamin D3 in a sample of blood.
Professionals like Hansen acknowledge that living in a northern location has its drawbacks.
""Living in Wisconsin is a risk factor for vitamin D deficiency,"" she said.
