Survey of current vitamin D food fortification practices in the United States and Canada.

Widespread poor vitamin D status in all age and gender groups in the United States (USA) and Canada increases the need for new food sources. Currently ∼60% of the intake of vitamin D from foods is from fortified foods in these countries. Those groups in greatest need are consuming significantly lower amounts of commonly fortified foods such as milk. Both countries allow voluntary vitamin D fortification of some other foods, although in Canada this practice is only done on a case-by-case basis. Novel approaches to vitamin D fortification of food in both countries now include "bio-addition" in which food staples are fortified through the addition of another vitamin D-rich food to animal feed during production, or manipulation of food post-harvest or pre-processing. These bio-addition approaches provide a wider range of foods containing vitamin D, and thus appeal to differing preferences, cultures and possibly economic status. An example is the post-harvest exposure of edible mushrooms to ultraviolet light. However, further research into safety and efficacy of bio-addition needs to be established in different target populations. This article is part of a Special Issue entitled 'Vitamin D Workshop'. Published by Elsevier Ltd.