White bread is made from
wheat flour from which the bran and the germ have been
removed through a process known as milling. Milling gives
white flour a longer shelf life by removing the bran which
contains oil, allowing products made with it, like white
bread, the ability to survive storage and transit times.
addition, the flour used in white bread is often bleached
using potassium bromate or chlorine dioxide gas to remove
any slight yellow color and make its baking properties
While the milling process helps improve white flour's
shelf life, it does remove nutrients like some dietary
fiber, iron, B vitamins and micronutrients. Since 1941,
however, fortification of white flour-based products with
some of the nutrients lost in milling, like thiamin,
riboflavin, niacin, and iron was mandated by the US
government in response to the vast nutrient deficiencies
seen in US military recruits at the start of World War II.
This fortification led to nearly universal eradication of
deficiency diseases in the US, such as pellagra and
beriberi (deficiencies of niacin and thiamine,
respectively) and white bread continues to be an important
source of these key vitamins to this day.
Folic acid is another nutrient that some governments have
mandated is added to enriched grains like white bread. In
the US and Canada, these grains have been fortified with
mandatory levels of folic acid since 1998 because of its
important role in preventing birth defects (2). Since
fortification began, the rate of neural tube defects has
decreased by approximately one-third in the US, resulting
in a cost savings.