Lisa Harnack, director of the Nutrition Coordinating Center and professor of epidemiology at the University of Minnesota's School of Public Health, says many Americans don't get enough vitamin D in their diets to meet recommended intake levels.
"Both men and women have shown a steady decrease in their vitamin D intake," Harnack says in a statement.
Harnack says people -- especially those living in the north -- should aim to include vitamin D rich foods in their diets on a daily basis this winter, including:
-- All types of dairy milk are fortified (added) with vitamin D. However, some brands of soy, rice and other non-dairy milks are fortified with vitamin D while others are not. Read the label to make sure.
-- Some brands of cereal, yogurt, margarine and orange juice are fortified with vitamin D.
-- Some foods like fish and mushrooms naturally contain vitamin D.
The list of foods that are naturally good sources of vitamin D is short, so as people spend less time outdoors in the fall and winter they need to rely on food products fortified with vitamin D to get sufficient vitamin D in their daily diets, Harnack says.