Prevalence of vitamin D insufficiency in Canada and the United States: importance to health status and efficacy of current food fortification and dietary supplement use.
Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, HFS-025, 8301 Muirkirk Road, Laurel, MD 20708, USA.
Several recent studies have identified a surprisingly high prevalence of vitamin D insufficiency in otherwise healthy adults living in Canada and the United States. Most striking are the effects of latitude, season, and race. Also noteworthy is that dietary vitamin D is not reaching the population in greatest need, nor is it very protective against insufficiency. Fluid milk, as the predominant vehicle for vitamin D fortification, is apparently not very effective in staving off vitamin D insufficiency in adults in all populations at all times of the year.