Fortification and Enrichment of Whole-Grain Wheat Flours: The Case for Folic Acid
For many children, the favorite foods are all the same: French fries, pizza, sausages in all shapes and forms, candy, and white bread. For a short period of time, however, my daughter bucked the white bread trend: she was also a chocoholic and ate dark brown bread readily in the hope that it was chocolate-flavored. Ms Almost-Five has wised up to the situation, and like “normal” children she also prefers white bread.
This preference for white bread lies at the heart of the history of flour enrichment. As Wilder reports, back in 1939, scientists were concerned with the move towards nutritionally inferior yet immensely popular white bread, that had been made financially accessible to the wider population through the use of modern roller milling techniques. The flour industry reportedly “feared a return to the rough, gray flour of the past” yet there was a clear need to replace the nutrients that were being removed by the rollers along with the delicate and nutritionally dense aleurone layer. The development of vitamin production techniques for thiamin, niacin and riboflavin allowed flour millers in developed countries to meet consumer demand for white bread while preventing deficiency diseases such as beriberi and pellagra. This technique is called enrichment: it aims to put back into the flour what has been removed. From the table below, it is clear that adding riboflavin, thiamin, niacin and iron to white flour produces a flour that is nutritionally equivalent to whole-grain wheat flour for these nutrients.
|Flour type||USDA food database number||Folate (DFE)||Thiamin (mg)||Riboflavin (mg)||Niacin (mg)||Iron (mg)|
|Wheat flour, white, all-purpose, unenriched||20481||26||0.12||0.04||1.3||1.2|
|Wheat flour, white, all-purpose, enriched||20581||291||0.79||0.49||5.9||4.6|
|Wheat flour, whole-grain||20080||44||0.50||0.17||5.0||3.6|
Since 1996 in the US and Canada, and later in other countries, wheat flour has been fortified with folic acid to prevent neural tube defects. Fortification differs from enrichment in that it adds a micronutrient to a foodstuff to increase its content to levels greater than are normally found. The table shows the main difference between whole-wheat flour and enriched flour is that whole-grain wheat flour has a naturally low level of folic acid, and cannot make a nutritionally meaningful contribution to folic acid intakes at normal levels of consumption. Yet, we are encouraged to consume more whole grain for its other health benefits. The problem is clear: people may be at risk of folic acid deficiency if they consume predominantly whole grains and do not have adequate intakes of folic acid from other sources. This is the reason why Chan, MacFarlane and O’Connor have recently modelled the effect of folic acid fortification of whole-grain wheat flour on folate status. They used data derived from 24-hour dietary recalls conducted on 35,000 Canadians during the 2004 Canadian Community Health Survey. For their model, the authors recalculated the folic acid content of whole-wheat flour foods so that they would contain the same amount of folic acid as similar enriched-flour products. They also derived a category of “whole wheat consumers”, identified as people who consumed a food containing whole wheat at least once during the dietary recall.
When the authors modeled the effect of fortification of whole wheat on the entire population, the prevalence of folate deficiency decreased a little compared to the standard situation. However, only one third of the sample consumed at least one product containing whole wheat during the 24-hour dietary recall, therefore two thirds of the population would not be affected by extending the fortification program to whole wheat. The prevalence of inadequate folate intake in whole wheat consumers was considerably higher than for the general population. When looking only at people consuming at least a portion of their cereal products as whole-wheat, the overall prevalence of inadequate folate intake halved from 21% to 10% in non-supplement users, and from 26% to 13% in supplement users when foods alone were considered. While the authors did not analyze the effect of folic acid fortification in women whole-wheat consumers of childbearing age, this age group appears to be at particular risk of inadequate folate intake, and an even larger absolute reduction in inadequate intakes could be expected.
While it seems that whole-grain flour still only makes up around 6% of all flour produced in the US, this is triple the amount in 2002-2003. The International Food Information Council reports that there is still strong consumer interest in consuming whole-grain products for their health benefits related to dietary fiber and phytonutrients. With fortification, whole-wheat could become a good source of folic acid as well.
Yen-Ming Chan, Amanda J MacFarlane, and Deborah L O’Connor. Modeling Demonstrates That Folic Acid Fortification of Whole-Wheat Flour Could Reduce the Prevalence of Folate Inadequacy in Canadian Whole-Wheat Consumers. J. Nutr. jn217851; first published online September 30, 2015. doi:10.3945/jn.115.217851
International Food Information Council (IFIC). 2015. Food & Health Survey 2015. http://www.foodinsight.org/sites/default/files/2015-Food-and-Health-Survey-Full-Report.pdf
Gary Vocke, Jean C. Buzby, and Hodan Farah Wells. Consumer Preferences Change Wheat Flour Use. September 01, 2008. http://www.ers.usda.gov/amber-waves/2008-september/consumer-preferences-change-wheat-flour-use.aspx
Wilder RM. A BRIEF HISTORY OF THE ENRICHMENT OF FLOUR AND BREAD. JAMA. 1956;162(17):1539-1541. doi:10.1001/jama.1956.72970340006010
World Grain Staff. Whole wheat flour output larger than thought. 5/6/2015. http://www.world-grain.com/articles/news_home/World_Grain_News/2015/05/Whole_wheat_flour_output_large.aspx