Fortification of wheat flour
Biological, behavioural and contextual rationale
Large scale fortification of staple foods is an effective, simple, and inexpensive strategy to improve the nutritional quality of the food supply through increasing vitamin and mineral content (1). Over 1.6 billion people (a quarter of the world’s population) are anaemic, with the highest prevalences among preschool children (47%) and pregnant women (37%) (2-4), resulting in considerable negative health, development and economic consequences (5). Globally, an estimated 700 million metric tons of wheat flour was processed for consumption in 2014/2015 (6), making wheat flour a good vehicle for fortification. Many affluent countries have had programmes for fortification of flour with micronutrients for over 75 years, but most anaemia now occurs in low- and middle-income countries (LMIC) where there have been relatively few fortification programmes of national staple cereals until recently (7).
Although iron deficiency is the most common cause of anaemia globally, other nutritional deficiencies (particularly folate, vitamin B12, vitamin A, copper), ill-health and infections, and haemoglobinopathies can all be causes (8). Populations consuming diets that mainly comprise of cereals with an inadequate intake of bioavailable, iron-rich foods are at high risk of micronutrient deficiencies. Mass fortification of cereal staples, such as wheat, is designed to reach the whole population and typically targets micronutrients, such as iron, thiamin, riboflavin, niacin and folic acid when these have been identified as public health problems (1, 9).
Micronutrient flour fortification programmes depend not only on regular consumption of the chosen vehicle across the entire population, the quantity of added iron and its bioavailability, but also on the organization of the industrial sector in a given country and enforcement of compliance by governments (9, 10). Both availability and accessibility are likely to be reduced in those communities isolated economically, geographically and developmentally. At a public health level, the implementation of long-term fortification programmes in many countries suggests a fairly minimal risk of mass fortification of cereals, but intakes may differ in sub-sections of the population (10). The largest theoretical risk is iron overload in susceptible individuals, but consumption of iron-fortified foods does not appear to increase risk (3).
Given the evidence from countries that have long-standing food fortification programmes along with guidance from WHO, FAO and other sources, many LMIC countries have begun fortifying staple foods (7, 9, 10). Globally, over 80 countries have legislation to fortify wheat flour, 14 countries have legislation to fortify maize products, and six countries have legislation to fortify rice (11).* Estimates for 2016 are that 34.1% of the world’s industrially milled wheat flour is fortified with at least iron or folic acid through mandatory and voluntary efforts (11).
Folic acid fortification has been found to substantially reduce the incidence of neural tube defects in a number of countries including several in North and South America, Iran, Jordan, and South Africa (10, 14). Chile, for example, showed a 55 % reduction in neural tube defect prevalence between 1999 and 2009. Iron fortification of food results in an increase in hemoglobin and serum ferritin levels, and a reduced risk of being anaemic or iron deficient (12). There is some evidence that after controlling for time effects, HDI (the Human Development Index) and endemic malaria, anaemia prevalence has decreased significantly in countries that fortify flour with micronutrients, while remaining unchanged in countries that do not (13). In 2012, the 65th World Health Assembly endorsed resolution WHA65.6 which established goals for the improvement of maternal, infant and young child nutrition by 2025, including a 50% reduction (from 2011 levels) in the number of women of reproductive age affected by anaemia. The increasing fortification of staple foods will be an important part of achieving that target.
* The WHO Global database on the Implementation of Nutrition Action (GINA) contains up to date information on national nutrition policies, including legislation on fortification (https://www.who.int/nutrition/gina/en/)
1. Recommendations on Wheat and Maize Flour Fortification Meeting Report: Interim Consensus Statement. Geneva: World Health Organization; 2009 (http://www.who.int/nutrition/publications/micronutrients/wheat_maize_fort.pdf).
2. Stevens GA, Finucane MM, De-Regil LM, Paciorek CJ, Flaxman SR, Branca F, Peña-Rosas J-P, Bhutta ZA, Ezzati M, on behalf of Nutrition Impact Model Study Group (Anaemia). Global, regional, and national trends in haemoglobin concentration and prevalence of total and severe anaemia in children and pregnant and non-pregnant women for 1995-2011: a systematic analysis of population-representative data. Lancet Global Health. 2013; 1(1), p. e16-25.
3. Pasricha SR, De-Regil LM, Garcia-Casal MN, Burford BJ, Gwirtz JA, Peña-Rosas JP. Fortification of maize flour with iron for preventing anaemia and iron deficiency in populations. Cochrane Database of Systematic Reviews. 2012; Issue 11. Art. No.: CD010187.
4. Guideline: Daily iron supplementation in infants and children. Geneva: World Health Organization; 2016 (http://www.who.int/nutrition/publications/micronutrients/guidelines/daily_iron_supp_childrens/en/).
5. Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, de Onis M, Ezzati M, Grantham-McGregor S, Katz J, Martorell R, Uauy R, and the Maternal and Child Nutrition Study Group. Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet. 2013; 382(9890):427-51.
6. International Grains Council. Grain Market Report – GMR 473. 19 January 2017 (http://www.igc.int/downloads/gmrsummary/gmrsumme.pdf).
7. Darnton-Hill I, Nalubola R. Food fortification as a public health strategy to meet micronutrient needs - successes and failures. Proceedings of the Nutrition Society. 2002; 61:231-241.
8. Peña-Rosas JP, Field MS, Burford BJ, De-Regil LM. Wheat flour fortification with iron for reducing anaemia and improving iron status in populations. Protocol. Cochrane Database of Systematic Reviews. 2014; Issue 9. Art. No.: CD011302.
9. Guidelines on food fortification with micronutrients. Allen L, de Benoist B, Dary O, Hurrell R (eds.). Geneva: World Health Organization/Food and Agricultural Organization of the United Nations; 2006 (http://www.who.int/nutrition/publications/micronutrients/9241594012/en/).
10. Dwyer JT, Wiemer KL, Dary O, Keen CL, King JC, Miller KB, et al. Fortification and health: challenges and opportunities. Advances in Nutrition. 2015; 6, 124-131.
11. Say hello to a fortified future: 2016 year in review. Atlanta: Food Fortification Initiative; 2016 (http://ffinetwork.org/about/stay_informed/publications/documents/FFI2016Review.pdf).
12. Gera T, Sachdev HS, Boy E. Effect of iron-fortified foods on hematologic and biological outcomes: systematic review of randomized controlled trials. American Journal of Clinical Nutrition. 2012; 96, 309–324.
13. Barkley JS, Wheeler KS, Pachón H. Anaemia prevalence may be reduced among countries that fortify flour. British Journal of Nutrition, 2015, 114, 265-273. doi:10.1017/S0007114515001646.
14. Castillo-Lancellotti C, Tur JA, Uauy R. Impact of folic acid fortification of flour on neural tube defects: a systematic review. Public Health Nutr. 2013;16(5):901-11.
The named authors alone are responsible for the views expressed in this document.
Declarations of interests
Conflict of interest statements were collected from all named authors and no conflicts were identified.