Lesson: The Minerals We Eat: Iron-Fortified Breakfast

Contributed by: Engineering K-PhD Program, Pratt School of Engineering, Duke University

A photograph shows a girl at a table with a bowl of flaked cereal.
Some cereals are fortified with extra minerals.
Copyright © Scott Bauer, U.S. Department of Agriculture http://www.ars.usda.gov/is/graphics/photos/dec02/k10137-1.htm


Students learn that minerals are a necessary part of our diets and that different minerals have different functions in the body. More specifically, they discover that iron is necessary to carry oxygen throughout our bodies. In the associated activity, students design a process to reverse engineer an iron-fortified cereal to determine how much iron it contains by removing most of the iron from the cereal.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

One of the many things that food engineers do is fortify cereals and other foods with different minerals that are important to our diets. The process of reverse-engineering is often used by engineers to better understand how existing products work or to fully understand their compositions.

Pre-Req Knowledge

Students should have an understanding of the primary molecules in food: fats, sugars, starches, proteins, etc.

Learning Objectives

After this lesson, students should be able to:

  • Explain that minerals are an important part of our diets.
  • Explain that different minerals have different roles in our health and state some of them.
  • Describe why iron is an important part of our diets.
  • List several foods that contain iron.
  • Describe why food engineers add iron and other minerals to cereal.
  • Explain that the iron in our cereal is the same iron that is attracted to magnets.

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Educational Standards

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In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

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  • Explain how magnets interact with all things made of iron and with other magnets to produce motion without touching them. (Grade 4) Details... View more aligned curriculum... Do you agree with this alignment?
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How many of you have seen an advertisement on television that said a cereal was fortified with vitamins and minerals? Have you ever had orange juice with calcium added to it? What do you think is going on with these things? Well, today we are going to answer all of these questions.

Minerals are natural compounds that are a necessary part of our diets. They help our bodies perform many vital functions. For example, they help us build bones and teeth, transmit nerve impulses, make hormones, and maintain a normal heartbeat. Thus, what we eat is very important, so that we get enough minerals in our daily diets. So food engineers fortify many common processed foods with extra minerals. This means that they add minerals to foods that do not usually contain them.

Today, we are going to learn about minerals. We will learn about the roles that calcium, iron, potassium and zinc play in the body. Then, we are going to design a process to remove one mineral, iron, from cereal. By doing this we will be reverse engineering.

Lesson Background and Concepts for Teachers

Minerals help your body grow and stay healthy. The body uses minerals to perform several functions. For example, they help you build bones and teeth, transmit nerve impulses, make hormones and maintain a normal heartbeat.

One important mineral is iron. Your entire body needs oxygen to stay healthy and alive and your body needs iron to transport oxygen from your lungs to the rest of your body. Iron helps this process because it's important in the formation of hemoglobin. Hemoglobin is the part of your red blood cells that carries oxygen throughout the body. Many foods are naturally iron rich, such as meat (especially red meat), tuna, salmon, eggs, beans, potato skins and leafy green vegetables.

People who do not get enough iron in their diets can become anemic. Anemia is a condition in which not enough red blood cells are present in the blood. A lack of red blood cells results in a lack of hemoglobin, which carries oxygen. If the blood cannot carry enough oxygen to the rest of the body, problems can occur. The main symptom of anemia is fatigue, but also sometimes chest pains and shortness of breath. People with anemia tend to have pale, pallid skin. Other effects of not getting enough iron include a decreased immunity to disease. Also, children who lack enough iron in their diet do not develop normally.

While many foods are naturally rich in iron, many people have trouble getting enough in their diets. So, food engineers often add iron to foods such as cereal. The process to fortify the cereal is quite simple. The food engineers simply mix powdered iron with the other cereal ingredients. Several types of powdered iron can be used, but the most common types are ferrous sulfate and ferrous fumerate. When ingested, it is converted into iron that can be used by the body in your stomach. The iron mixes with the hydrochloric acid in your stomach to make iron chloride and oxygen gas. The iron chloride is absorbed by your small intestines. The amount of iron added to food is dependent on several factors. For example, the prevalence of iron deficiency in the group and the dietary trends of a culture contribute to how much iron should be added to cereal. Food engineers also add other types of minerals and vitamins to different foods. For example, orange juice is often fortified with calcium.

Because not everyone eats cereal, food engineers create ways to deliver essential nutrients to people and kids in some of the world's poorest places. For example, some scientists and engineers have developed rice and salts that are fortified with different vitamins and minerals, including iron. This helps children all over the world receive more nutrients in their diets because rice and salt are often consumed in many different cultures.

In this lesson/activity, we will show that the iron found in food is the same type of iron that is attracted to magnets. Students discover this by engineering a process to remove the iron in cereal, essentially a reverse-engineering process.


calcium: A mineral that is helpful in building bones and teeth.

fortify: To add one or more ingredients to a food to increase its nutritional content.

iron: A mineral that is necessary to transport oxygen around the body (part of hemoglobin).

magnet: An object or device that produces a magnetic field that attracts other magnets and certain metals.

mineral: A natural compound that is important in helping the body perform many vital functions.

potassium: A mineral that helps keep the muscles and nervous system working well.

zinc: A mineral that helps the immune system.

Associated Activities

Lesson Closure

(Once the associated activity is completed, wrap up the lesson.) How were you able to remove iron from the cereal? Why do you think crushing the cereal (or other methods used) worked better? After your experiment, how do you think that food engineers add the iron to the cereal?

While this process may sound difficult, it is consider necessary if you do not otherwise get enough iron in your diet. Iron has an important role in carrying oxygen around the body; if you do not get enough iron you can feel tired. Not having enough iron over a long period of time can affect your growth.


Pre-Activity Assessment

What does iron make you think of? Ask students to brainstorm what iron makes them think of. See if they can make the connection between magnets and iron in food.

Changed Food: Ask students to brainstorm some foods that they have eaten or seen that have extra nutrition added, or are especially formulated to have specific items removed, such as gluten.

Activity Embedded Assessment

Iron Removal Plan: After the lesson is introduced, ask students to write a quick plan to get the iron out of the cereal. Ask them to explain why they chose their methods. Examine and approve their plans before they begin work.

Post-Activity Assessment

Guide to Iron Removal: Ask students to write or draw the steps of the process they used to remove the iron from the cereal. Suggest that the students act as if they are food engineers, making a manual for other people.

Removing Other Minerals: Ask students to think about other foods from which they could remove iron or another mineral. Ask them to make another plan for this process.

Lesson Extension Activities

Have students test the iron content of different cereals. The procedure to do this is the same as in the activity repeated three times. After students have measured the iron content in the different cereals, they can create a bar graph of the amount of iron in each cereal.

Discuss how engineers add specific components to food such as other minerals and vitamins. Assign students to make a search at the grocery store, looking at the packages of processed food, and report their findings back to the class.


Dietary Supplement Fact Sheet: Iron. Updated July 26, 2005. Office of Dietary Supplements. National Institute of Health. Accessed April 26, 2007.

Minerals. Reviewed August 2004. Kids Health. Nemours Foundation. Accessed April 26, 2007. http://www.kidshealth.org/kid/stay_healthy/food/minerals.html

Matsui MD, William. MedlinePlus Medical Encyclopedia: Anemia. 2005. A.D.A.M., Inc. Accessed April 26, 2007. http://www.nlm.nih.gov/medlineplus/ency/article/000560.htm

Guidelines for Iron Fortification of Cereal Food Staples. May 2001. Sustain: Sharing U.S. Technology to Aid in the Improvement of Nutrition. Accessed April 26, 2007.


Liz Harper


© 2013 by Regents of the University of Colorado; original © 2007 Duke University

Supporting Program

Engineering K-PhD Program, Pratt School of Engineering, Duke University


This content was developed by the MUSIC (Math Understanding through Science Integrated with Curriculum) Program in the Pratt School of Engineering at Duke University under National Science Foundation GK-12 grant no. DGE 0338262. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: February 17, 2018