A study released by the University of Colorado Denver School of Medicine found that 75 percent of Americans do not get enough Vitamin D, up from 50 percent 20 years ago. As Vitamin D is often called the "sunshine vitamin," the analysis concluded that American outdoor behaviors have changed and that the nation is simply not spending enough time outside.
Researchers are continuing to associate Vitamin D with positive health attributes.
According to the National Institute of Health's Office of Dietary Supplements
, Vitamin D is "naturally present in very few foods," so there are few substitutes for exposure to sunlight. The vitamin is found in fish - such as salmon, tuna, and mackerel. Fish liver oils are among the best sources of Vitamin D. It is also found in small amounts in beef liver, cheese, egg yolks and in some mushrooms.
Vitamin D is essential to promoting the absorption of calcium, and deficiencies are often tied to bone development issues. However, "Vitamin D has other roles in human health, including modulation of neuromuscular and immune function and reduction of inflammation," states NIH.
Recent studies have also found that many different cells in the body have Vitamin D receptors, suggesting a wider variety of impact to overall health. Vitamin D is known to regulate 1,000 genes and is suspected in playing a role in cardiovascular health and in preventing certain cancers.
Vitamin D is relatively abundant through supplements and through sunlight. 10 minutes of uncovered sunlight exposure daily provides ample dosage.
Dr. Adit Ginde, one of the researchers behind the University of Colorado study, told Reuters in a telephone interview, "But people's habits have changed ... they are less active and outdoors less, and also protecting their skin from the sun because of skin cancer risk."
The findings were published in the Archives of Internal Medicine.