Iron 101: An Essential Mineral

Iron is a micronutrient the body needs for proper functioning and development. It is an essential mineral that makes hemoglobin, a protein found in red blood cells. This protein helps blood carry oxygen to our lungs and to the rest of our body! Iron also helps the body make myoglobin, a protein that provides our muscles with oxygen.

Iron in the body

Red blood Cells

Iron can be found throughout the body, approximately 70% of our body’s iron is found in hemoglobin (protein) in red blood cells. Another 25% of it is stored in ferritin, a protein in our cells and blood, and through different mechanisms in the body ferritin will release iron when the body needs it. The remaining 6% is found in other essential proteins.

If someone’s iron levels are low over a prolonged period of time this is when iron stores (ferritin) could become depleted and hemoglobin levels can become low.

What does iron do for us?

As iron is an essential mineral it performs many important functions in the body, the main role is transporting oxygen to the lungs and the rest of the body, it also provides us with energy through its role in metabolism, and helps with proper immune function.

• Hemoglobin and Myoglobin: It is important to have iron available to make hemoglobin, a protein responsible for transporting oxygen to the body’s tissues from the lungs. Myoglobin’s main function is to provide oxygen to the cells in our muscles including heart muscles and the ones attached to our bones and tendons. To produce a proper myoglobin protein, iron is needed.

• Energy: Iron gives our body energy in a few mechanisms. As iron is crucial for the transportation of oxygen to all parts of the body, this gives your brain, muscles, and heart energy to properly function. Iron is also needed for certain enzymes in the body to function, in particular, one of the enzymes needed for the process of converting our nutrients to energy uses iron.

• Immune system: Iron plays an important role in the immune system through its connection with cells of the innate (the body’s first line of defense against germs) and adaptive (our built-up immunity) immune system. Cells like neutrophils and natural killer cells are used to fight against pathogens and bacteria in the body, and iron is used for the activation and functioning of these cells. Iron also helps increase antibody response.

Dietary iron

There are two types of dietary iron, heme iron and non-heme iron. Heme iron is only found in animal-derived food sources such as meat, poultry, and fish whereas non-heme is found in both animal and plant-derived foods, such as eggs, beans, lentils, nuts/seeds, whole grains, and some vegetables. Heme iron has a higher absorption rate than non-heme iron which makes it more available to the body for use. When consumed, approximately 25 % of heme iron will be absorbed into the body, and 17% of non-heme iron will be absorbed.

Different factors can enhance or inhibit the absorption of iron

Iron absorption enhancers

• Ascorbic acid: Studies have shown that vitamin C enhances the absorption of iron while also inhibiting the effects of phytates, polyphenols, and calcium (iron absorption inhibitors). Adding foods such as citrus fruits, tomatoes, and broccoli to your meal can help enhance iron absorption!

• Meat, poultry, and fish: The heme iron found in meat, poultry, and fish have been shown to enhance the absorption of non-heme iron. So if you are eating a plant-based iron-containing food such as dark leafy greens pairing it with a piece of meat or fish can help enhance the absorption of the non-heme iron!

Inhibitors of iron absorption

• Phytates: foods like soybeans, black beans, and lentils are known to inhibit absorption of non-heme iron

• Polyphenols: these inhibit non-heme iron and are found in tea, coffee, wine, and some cereals and legumes

• Calcium: Calcium has been shown to inhibit both heme and non-heme iron

There are also other personal factors that can affect iron absorption. For example, a vegetarian diet will have less iron available for use as it only contains non-heme iron. If you follow a vegetarian diet, it is important you are consuming even more than the recommended daily amounts of iron. Women who have a menstrual cycle also lose iron through menstrual blood loss. During this time of the month try and be conscientious of your iron intake!

If you are concerned about your iron intake, because you have low iron, are following a plant-based diet, or another reason, book an appointment with one of our dietitians today!

Recommended Iron Intake

The following table shows the average daily recommended amounts of iron in milligrams (mg).

Sources of iron

Food Sources

Examples of Iron-containing Meats!

• Meat, poultry, fish, seafood

• Eggs

• Beans, peas, and lentils

• Dark leafy greens (spinach, kale, collard greens)

• Broccoli

• Fortified breakfast cereals and bread

• Nuts and Seeds (cashews, pistachios, sesame, pumpkin, flaxseed)

• Dried fruits (raisins, dates, prunes)

Supplements

Iron supplementation is another way to increase daily iron. There are lots of iron-containing vitamins as well as supplements that are just iron. However, we never recommend taking an iron supplement unless recommended by your primary care provider or dietitian as they can have health risks and side effects.

Cooking With Iron

A third way to increase your daily iron is cooking with iron. Using cast-iron cookware can increase the iron content in food! If you do not have a cast iron pan or do not want to cook in it everyday, you can also use iron ingots such as the Lucky Iron Fish or Leaf (pictured below) to increase the iron in your recipes.

Low Iron

Low intake over a prolonged period of time can lead to iron deficiency and even iron deficiency anemia. Anemia is a condition when your blood is lacking healthy blood cells. Without iron, the body can not produce enough hemoglobin (protein that carries oxygen), often leading to iron-deficiency anemia. The body may not show signs but if the condition progresses the following are possible symptoms:

• Pale skin

• Extreme fatigue

• Headache, dizziness

• Chest pain, shortness of breath

• Brittle nails

• Cold hands and feet

• Inflammation or soreness of the tongue

Iron is an essential mineral needed by the body for many different functions, being aware of your iron intake can help you feel energized, healthy, and ensure your iron stores are plentiful!

If you have been diagnosed with iron deficiency or curious about your iron intake, book an appointment with one of our dietitians for a full nutrition assessment.

Work cited:

Abbaspour, Nazanin, Richard Hurrell, and Roya Kelishadi. “Review on iron and its importance for human health.” Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences 19.2 (2014): 164. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999603/

American Society of Hematology. (2023). Iron Deficiency-Anemia. Available from: https://www.hematology.org/education/patients/anemia/iron-deficiency

Dev, S., & Babitt, J. L. (2017). Overview of iron metabolism in health and disease. Hemodialysis international, 21, S6-S20. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5977983/#:~:text=These%20iron%2Dcontaining%20proteins%20are,host%20defense%2C%20and%20cell%20signaling.

Iron functions in the body. Dr. Catherine Shaffer. (Jan 2023). Available from: https://www.news-medical.net/health/Iron-Functions-in-the-Body.aspx

National Institutes of health. (2023). “Iron”. Office of dietary supplements. Available from: https://ods.od.nih.gov/factsheets/Iron-Consumer/#:~:text=Iron%20is%20a%20mineral%20that,that%20provides%20oxygen%20to%20muscles.