Fortified Cereal: the First in a Serial Movement for Public Health

In the early 20th century, America was plagued. Not with disease but with nutritional deficiency, specifically iron deficiency. The population, at the time, had been suffering from widespread cases of iron deficiency anemia (Mitchell, 2024), which is a condition where one's body cannot produce enough hemoglobin because of the lack of iron, leading to reduced oxygen delivery throughout the bloodstream and symptoms of dizziness, fatigue, and shortness or breath. With high rates of iron deficiency anemia throughout America in 1941, companies began looking for solutions (Niemesh, 2015). The implementation a process called food fortification after World War II is largely considered a success in food systems and public health efforts, but are these efforts complete? How can we use food fortification to bolster our existing systems today?

Figure 1: Symptoms of iron deficiency anemia and why it was such a pressing issue in the 1940s.

The history of food fortification

Food fortification is the process of adding vitamins, minerals, and other essential micronutrients into food to increase their nutritional value for public health purposes. The first instance of food fortification in the US was fortifying salt with iodine to compensate for iodine deficiencies within the population (Leung et al., 2012). Later in the 1940s, when iron deficiency became a more u urgent public health issue, bread and flour products became a new target of interest. To expand from bread and flour products, people began to look for other alternatives (Whittaker et al., 2001). Due to its convenience and presence in approximately 90% of consumer households, cereal was a logical choice for the next fortified food (Amidor, 2020). 

More recently, in 1996, the FDA administered regulations to enrich cereals with folic acid (Whittaker et al., 2001), a synthetic form of the compound folate (“Folate”, 2012) which is essential in protein metabolism. Folic acid also plays key roles in producing healthy red blood cells, which is necessary for women during pregnancy and fetal development. These changes were implemented to reduce the chances of neural tube defects during pregnancy. Now, cereal has been fortified to also include various B vitamins, vitamin A, vitamin D, vitamin E, calcium, and zinc (Fortified Cereals, n.d.).

Figure 2: Nutrition Facts of Honey Nut Cheerios. Note the percentages of each micronutrient, vitamin, and mineral.

The process of fortifying cereal with iron

To fortify cereal specifically for iron, non-heme iron is typically used. Non-heme iron is derived from plants and is commonly found in plant-based foods. It is not to be confused with heme iron which comes from animal products since it binds to animal proteins and muscular tissue. Non-heme iron can also be isolated from animal products, but that is only due to the fact that some animals consume plant sources (“Iron,” 2019). 

Non-heme iron makes up the majority of western diets, approximately 85-90%. Unlike heme iron, it is less easily absorbed into the body, but it can be enhanced with the consumption of vitamin C, perfect when drinking a glass of orange juice, for example (Tan, 2017).

The specific form of non-heme iron is typically found in the form of ferrous sulfate or electrolytic iron that is added during manufacturing of the cereal. These compounds are mixed into the dough before being shaped and baked (Rabinowitz, 2025). Using non-heme is also stable, cost-effective, and easy to incorporate into processed foods without altering their texture (Panoff, 2024).

Figure 3: Schematic of how flour products are fortified.

Downsides to Fortified Cereal

Although fortified cereal provides necessary nutrients as opposed to unfortified cereals, people should still cautiously consume them. One study conducted in 2001 by Whittaker et al. found that the majority of cereal brands contain more than the labeled percentages of both folic acid and dietary iron (Whittaker et al., 2001). And, with most consumers eating more than one serving size per day, they may be at risk for overconsuming these nutrients. Eating cautiously and in moderation is the best way to prevent excessive intake.

Cereals also tend to be high in added sugars. In fact, according to the Dietary Guidelines for Americans, breakfast cereals are one of the highest sources of added sugar in an American’s diet. Additionally, because of the additional processing fortification brings, most cereals are low in fiber, which is necessary for healthy digestion (Foley, 2026). This poses the question, can cereal fortification only come at the expense of exacerbating other nutritional needs?

In addition, one study demonstrated that calcium may inhibit how much non-heme iron is taken up. With milk as a high source of calcium, cereal paired with milk may not be conducive to optimal iron absorption in the intestinal lining. In a paper written by Lönnerdal, a researcher at the University of California-Davis in 2010, it is mentioned that calcium binds to the same protein—called the divalent metal transporter 1 (DMT1)—as non-heme iron and engages in competition or interference. If calcium binds the DMT1 protein first, then the non-heme iron cannot, and therefore, non-heme iron has a harder time being absorbed by intestinal cells.

Figure 4: Iron uptake by enterocytes (intestinal absorptive cells). The process by which dietary iron (Fe) is absorbed into the cell through the DMT1 protein. If calcium was present, it could take up the space in the DMT1 receptor that the iron binds to, rendering iron absorption more difficult.

Towards the end of the study, the study speculates that calcium inhibition may only be short-term, and show no concern to long-term effects (Lönnerdal, 2010); however, another study from 2011 observed that calcium may cause greater inhibition when consumed in more than 800mg or the equivalent of milk in about 2.5 servings of cereal (Gaitán et al., 2011). If even the most obvious confounding variable, milk, can obstruct the initial purpose of fortified cereal, what are other factors influencing iron absorption that have not been considered yet? 

Key Takeaways

Fortified cereal is a primary example of how the food systems that can be redesigned to benefit public health are oftentimes also imperfect and incomplete. Although the government was future-oriented to recognize iron deficiency as an urgent public health crisis, was it executed well? Are there ways to fortify food without drawbacks? Can we improve how cereal delivers nutrients without raising added sugars or diminishing fiber? What are other factors that nutrition-related aspects fortification may have negatively impacted? Are there other foods capable of being fortified? Cereal serves as just one example of the questions that researchers, manufacturers, and public health experts still need to consider. The question of possibility still lies ahead, but with active engagement, knowledge, and innovation, there may be a future where food fortification will be beneficial, sustainable, and without the negative side effects seen now.

References

1. Amidor, T. (2020, March 16). Cereals and Fortified Nutrients: What You Need to Know About the Changing Levels. US News & World Report. https://health.usnews.com/health-news/blogs/eat-run/articles/cereals-and-fortified-nutrients

2. Folate (Folic Acid)—Vitamin B9 • The Nutrition Source. (2012, September 18). The Nutrition Sources. https://nutritionsource.hsph.harvard.edu/folic-acid/

3. Foley, J. (2026, May 5). What Is Fortified Cereal? Benefits, Drawbacks, and How to Choose—GoodRx. GoodRx. https://www.goodrx.com/well-being/diet-nutrition/what-is-fortified-cereal

4. Fortified Cereals—Vitamins and Minerals. (n.d.). Nestlé Cereals. Retrieved February 8, 2026, from https://www.nestle-cereals.com/mena/me-en/nutrition/fortification

5. Gaitán, D., Flores, S., Saavedra, P., Miranda, C., Olivares, M., Arredondo, M., López de Romaña, D., Lönnerdal, B., & Pizarro, F. (2011). Calcium does not inhibit the absorption of 5 milligrams of nonheme or heme iron at doses less than 800 milligrams in nonpregnant women. The Journal of Nutrition, 141(9), 1652–1656. https://doi.org/10.3945/jn.111.138651

6. Iron. (2019, September 16). The Nutrition Source. https://nutritionsource.hsph.harvard.edu/iron/

7. Leung, A. M., Braverman, L. E., & Pearce, E. N. (2012). History of U.S. Iodine Fortification and Supplementation. Nutrients, 4(11), 1740–1746. https://doi.org/10.3390/nu4111740

8. Lönnerdal, B. (2010). Calcium and Iron Absorption—Mechanisms and Public Health Relevance. International Journal for Vitamin and Nutrition Research, 80(45), 293–299. https://doi.org/10.1024/0300-9831/a000036

9. Mitchell, K. (2024, February 23). Iron Deficiency Anemia (Low Iron): Symptoms, Causes, Treatment. WebMD. https://www.webmd.com/a-to-z-guides/iron-deficiency-anemia

10. Niemesh, G. T. (2015). Ironing Out Deficiencies: Evidence from the United States on the Economic Effects of Iron Deficiency. Journal of Human Resources, 50(4), 910–958. https://doi.org/10.3368/jhr.50.4.910

11. Panoff, L. (2024, May 31). Iron in Baby Cereal: Best Uses, Safety, and the... Else Nutrition. https://elsenutrition.com/a/resources/nutrition/iron-in-baby-cereal-importance

12. Rabinowitz. (2025, September 25). High Iron Cereal & Iron Fortified Cereals. Smart Eats. https://smarteatspantry.com/blogs/iron/guide-to-iron-fortified-cereals

13. Tan, V. (2017, June 3). How to Increase the Absorption of Iron from Foods [4/24/2023]. Healthline. https://www.healthline.com/nutrition/increase-iron-absorption

14. Whittaker, P., Tufaro, P. R., & Rader, J. I. (2001). Iron and folate in fortified cereals. Journal of the American College of Nutrition, 20(3), 247–254. https://doi.org/10.1080/07315724.2001.10719039

Thumbnail image: Courtesy of Rachel Linder from Eat this, Not That!