Iron: Deficiency & Toxicity Symptoms

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  • 0:01 Iron & Its Functions
  • 1:50 Sources
  • 3:12 Deficiency
  • 4:35 Toxicity
  • 6:14 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Iron is a trace mineral that your body gets from a variety of animal and plant foods. It has many functions, including making hemoglobin. Learn how low iron can lead to iron deficiency anemia and the health consequences associated with iron toxicity.

Iron and Its Functions

When you cut your finger, red blood comes out, but is blood always red, even when it's inside your body? The answer is yes, and we can attribute the red color to the fact that your blood cells contain hemoglobin, which is an iron-containing protein responsible for transporting oxygen around your body. The prefix 'hemo' refers to blood, which might help you recall that hemoglobin is found in your blood cells. More specifically, the iron within hemoglobin attaches to oxygen, and it's this interaction between the iron and the oxygen that makes your blood cells red.

As you can imagine, moving oxygen around your body is a pretty important job, so much so that most of the iron that you consume through your diet can be found in hemoglobin. However, iron, which is a trace element, is needed for other functions as well. For example, it's part of myoglobin, which is a protein found in your muscles that makes oxygen available for muscle contractions. Do you see the prefix 'myo'? That means muscle, and you probably noticed that myoglobin and hemoglobin both end in 'globin.' This is because they both come from the same family of globular proteins, almost as if they are cousins in the oxygen-loving globin family.

In addition to the vital iron functions of being part of hemoglobin and myoglobin, iron is needed for energy production as it helps with the conversion of nutrients into ATP, which is the form of energy your body likes to use to carry out its functions. These are all pretty important jobs, so you can imagine that your body wants to maintain the right amount of iron; yet, this doesn't always work out, and in this lesson, we will take a look at what happens if there is too little or too much of this mineral inside of you.


You get iron from the foods you eat, but not all foods contain the same form of iron. Heme iron is an easily absorbed form of iron found in animal foods such as meats, poultry and fish. Nonheme iron is a less easily absorbed form of iron found in plant foods such as leafy green vegetables, legumes and grains. With nonheme iron sources, it is as if your body is saying no thanks to at least some of the iron you are trying to give it.

What we can take away from this is that animal foods are better sources of usable iron than plant foods. So it's easy to see that if you follow a diet that is low in animal products, you could be low on iron and at an increased risk of iron deficiency. This includes vegans, who do not consume any animal products, as well as vegetarians, who consume limited animal products. Once iron is inside of your body, it's not easily eliminated. One of the main ways of losing iron is through blood loss. This includes blood lost through a woman's monthly menstrual cycle. Therefore, women of childbearing age need more iron in their diet to avoid iron deficiency, as do individuals with greater need due to rapid growth and development, such as pregnant women and children.


If your iron intake is low or iron is lost from your body, then you could reach iron deficiency. If you recall that one of the main functions of iron is to help make hemoglobin, then it's easy to see that a deficiency of iron would lead to a deficiency of hemoglobin. This is a condition called iron deficiency anemia, which is defined as a decrease in the oxygen-carrying capacity of the blood due to insufficient iron to make hemoglobin. Do you remember that we said it's the interaction between iron and oxygen in the hemoglobin that gives blood its red color? Well, in iron deficiency anemia, we see that the red blood cells look pale and small due to the decreased iron.

And, if you think about the fact that your body cells are not getting enough oxygen delivered to them, then it is easy to see that the symptoms of iron deficiency anemia include fatigue, weakness, headaches and irritability. You might also notice that you have pale skin, shortness of breath, a rapid heartbeat and a strange appetite for ice or clay. This odd appetite is referred to as picophagia, and while the reason for these cravings is not fully understood, it may be the body's attempt to get what it needs. After all, iron, like other minerals, can be found in clay.


Iron can also cause symptoms if you take in too much and reach iron toxicity. We also see that iron can be stored in your body tissues and organs, which increases the likelihood of getting too much.

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