Iron is a micronutrient that the body needs for proper function and growth. It is an essential mineral that produces hemoglobin, a protein found in red blood cells. This protein helps blood carry oxygen to our lungs and the rest of our body! Iron also helps the body produce myoglobin, a protein that supplies our muscles with oxygen.
Red blood cells
Iron can be found throughout the body, about 70% of our body’s iron is found in the hemoglobin (protein) in red blood cells. Another 25% of this 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 one’s iron levels are low for a prolonged period of time, then iron stores (ferritin) could be depleted and hemoglobin levels may drop.
What does iron do for us?
As iron is an essential mineral, it performs many important functions in the body, the main role being the transport of oxygen to the lungs and the rest of the body, it also provides us with energy through its role in metabolism and helps the immune system function properly.
Hemoglobin and Myoglobin: It is important to have iron available for the production of hemoglobin, a protein responsible for carrying oxygen to body tissues from the lungs. Myoglobin’s main function is to deliver oxygen to our muscle cells, including our heart muscles and those connected to our bones and tendons. To produce a proper myoglobin protein, iron is required.
Energy: Iron gives our body energy through a few mechanisms. As iron is vital for transporting oxygen to all parts of the body, it gives your brain, muscles and heart energy to work properly. Iron is also necessary for the functioning of certain enzymes in the body, specifically, one of the enzymes required for the process of converting our nutrients into energy uses iron.
Immune system: Iron plays an important role in the immune system through its connection with the cells of the innate (the body’s first line of defense against germs) and the adaptive (our built immune system) immune system. Cells such as neutrophils and natural killer cells are used to fight pathogens and bacteria in the body, and iron is used to activate and function these cells. Iron also helps increase the antibody response.
There are two types of dietary iron, heme iron and non-heme iron. Heme iron is only found in animal sources such as meat, poultry and fish, while non-heme iron is found in both animal and plant 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, about 25% of the heme iron will be absorbed into the body and 17% of the non-heme iron will be absorbed.
Different factors can enhance or inhibit iron absorption
Iron absorption enhancers
Ascorbic acid: Studies have shown that vitamin C enhances iron absorption while also inhibiting the effects of plant salts, polyphenols and calcium (iron absorption inhibitors). Adding foods like citrus fruits, tomatoes and broccoli to your meal can help boost iron absorption!
Meat, poultry and fish: The heme iron found in meat, poultry and fish has been shown to enhance the absorption of non-heme iron. So if you eat a plant-based food that contains iron, like dark leafy greens, pairing it with a piece of meat or fish can help boost the absorption of non-heme iron!
Inhibitors of iron absorption
Vegetables: foods such as soy, black beans and lentils are known to inhibit the absorption of non-heme iron
Polyphenols: inhibit non-heme iron and are found in tea, coffee, wine and some grains 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 to consume even more than the recommended daily amounts of iron. Menstruating women also lose iron through menstrual blood loss. During this time of the month, try to watch your iron intake!
If you are concerned about your iron intake because you have low iron, follow a plant-based diet, or otherwise, make an appointment with one of our dietitians today!
The table below shows the average daily recommended amounts of iron in milligrams (mg).
Men and women 51 years and older | |
Examples of meats that contain iron!
Meat, poultry, fish, seafood
Dark leafy greens (spinach, kale, collard greens)
Enriched breakfast cereals and bread
Nuts and seeds (cashews, peanuts, sesame, pumpkin, flaxseed)
Dried fruits (raisins, dates, plums)
Iron supplements are another way to increase iron daily. There are many vitamins that contain iron as well as supplements that are just iron. However, we never recommend taking iron supplements unless recommended by your primary care provider or dietitian, as they can have health risks and side effects.
A third way to increase your daily iron is to cook with iron. Using cast iron cookware can increase the iron content of food! If you don’t have a cast iron pan or don’t want to cook in it every day, you can also use iron bars like Lucky iron fish or leaf (photo below) to increase the iron in your recipes.
Low intake over a prolonged period of time can lead to iron deficiency and even iron deficiency anemia. Anemia is a condition in which your blood lacks healthy blood cells. Without iron, the body cannot produce enough hemoglobin (an oxygen-carrying protein), often leading to iron deficiency anemia. The body may show no signs, but if the condition progresses, the following are possible symptoms:
Chest pain, shortness of breath
Inflammation or pain in 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 are curious about your iron intake, make an appointment with one of our dietitians for a complete nutritional assessment.
