Iron: Health Benefits, Types, Food Sources, and More


According to the National Institutes of Health iron is a mineral vital to the proper function of hemoglobin, a protein needed to transport oxygen in the blood and perfume other various processes. A shortage of iron in the blood can lead to a range of serious health problems including iron deficiency anemia. Around 10 million people in the United States have low iron levels, and roughly 5 million of these have been diagnosed with iron deficiency anemia. This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular vitamins and minerals. It provides an in-depth look at recommended intake of iron, its possible health benefits, foods high in iron and any potential health risks of consuming too much iron.

What is an Iron?

An essential mineral the body requires to produce hemoglobin, a component in the blood that transports oxygen from the lungs to tissues throughout the body. Iron is also crucial for many other proteins and enzymes needed by the body to support normal growth and development.

What are the Types of Iron?

There are two types of dietary iron known as heme and non-heme. Animal sources of food including meat and seafood, contain heme iron. Heme iron is more easily absorbed by the body. Non-heme, the type found in plants, requires that the body take multiple steps to absorb it. Plant based sources of it include beans, nuts, soy, vegetables, and fortified grains. The bioavailability of heme iron from animal sources can be up to 40%. Non-heme it from plant based sources however, has a bioavailability of between 2 and 20%. For this reason the RDA for vegetables is 1.8 times higher than for those who eat meat to make up for the lower absorption level from plant based diet. When following a vegetarian diet, it is also important to consider components of food and medications that block or reduce it absorption, Such as:

  • PPI and omeprazole use to reduce the acidity of stomach contents
  • Polyphenols in cereals and legumes as well as in spinach
  • Tannins in coffee, tea, some wine, and certain berries
  • Phosphate in carbonated beverages such as soda
  • Phytates in beans and grains

What are the Health Benefits of Iron?

It helps to prevent many vital functions in the body including general energy and focus gastrointestinal processes the immune system and the regulation of the body temperature. The benefits of it often go unnoticed until a person is not getting enough. The deficiency anemia can cause fatigue, heart palpitations, pale skin, and breathlessness.

Health Pregnancy:

Blood volume and red blood cell production increase dramatically during pregnancy to supply the growing fetus with oxygen and nutrients. As a result the demand for it also increased. While the body typically maximizes the iron absorption during pregnancy, insufficient intake or other factors affecting the way it is absorbed can lead to iron deficiency. Low iron intake during pregnancy increases the risk of premature birth and low birth weight as well as low iron stores and impaired cognitive or behavioral development in infants. Pregnant women with low iron may be more prone to infection because it also supports the immune system. It is clear that supplements are needed for women who are both pregnant and it-deficient. However, research is ongoing as to the possibility of recommending additional iron to all pregnant women, even those with normal levels.


Insufficient it in the diet can affect the efficiency with which the body uses energy. It carries oxygen to the muscles and brain is crucial for both mental and physical performance. Low levels may result in a lack of focus, increased irritability and reduced stamina.

Better Athletic Performance:

The deficiency is more common among athlete’s especially young female’s athletes, than in individuals who do not lead an active lifestyle. This appears to be particularly true in female endurance athletes such as long distance runners. Some experts suggest that female endurance athletes should add an additional 10 mg of elemental iron per day to the current RDA for iron intake. The deficiency in athletes decreases athletic performance and weakens immune system activity. A lack of hemoglobin can greatly reduce performance during physical exertion as it decreases the body’s ability to transport oxygen to the muscles.


It has low bioavailability meaning that the small intestine does not readily absorb large amounts. This decreases its availability for use and increases the likelihood of deficiency. The efficiency of absorption depends on a range of factors including:

  • The source of iron
  • Other supplements of the diet
  • Gastrointestinal health
  • Use of the medications or supplements
  • A person’s overall iron status
  • Presence of iron promotes such as vitamin C

What are the Sources of the Iron?

Some of the best sources of it include:

  • Canned clams: 3 ounces provides 26 mg of iron
  • Fortified, plain, dry cereal oats: 100 g provides 24.72 mg
  • White beans: One cup provides 21.09
  • Dark chocolate: (45 to 69% cacao) one bar provides 12.99 mg
  • Cooked pacific oyster: 3 oz provides 7.82 mg
  • Cooked spinach: 1 cup provides 6.43mg
  • Beef liver: 3 oz provides 4.17 mg
  • Boiled and drained lentils: Half cup provides 3.3 mg
  • Firm tofu: Half cup provides 2.03 mg
  • Boiled and drained chickpeas: Half a cup provides 2.37 mg
  • Canned, stewed, tomatoes: Half a cup provides 1.7 mg
  • Lean, ground beef: 3 oz provides 2.07 mg
  • Medium baked potato: This provides 1.87 mg
  • Roasted cashew nuts: 3 oz provides 2 mg

Calcium can show both heme and nonheme absorption. In most cases, a typical varied Western-style diet is considered balanced in terms of enhance and inhibitors of its absorption.

What are the Fast Facts of Iron?

  • The Recommended Daily Allowance (RDA) varies between ages but women who are pregnant require the most.
  • Iron promotes healthy pregnancy, increased energy and better athletic performance. Iron deficiency is most common in female athletes.
  • Canned claims fortified cereals and white beans are the best sources of dietary iron.
  • Too much iron can increase the risk of liver cancer and diabetes.

What is Recommended Intake of Iron?

The Recommended Daily Allowance (RDA) for elemental iron depends on a person’s age and sex. Vegetarians also have different iron requirements.


  • 0 to 6 months: 0.27 mg
  • 7 to 12 months: 11mg


  • 1 to 3 years: 7mg
  • 4 to 8 years: 10 mg


  • 9 to 13 years: 8 mg
  • 14 to 18 years: 11mg
  • 19 years and older: 8 mg


  • 9 to 13 years: 8mg
  • 14 to 18 years: 15mg
  • 19 to 50 years: 18 mg
  • 51 years and older: 8 mg
  • During pregnancy: 27 mg
  • When lactating between 14 and 18 years of age: 10 mg
  • When lactating at older than 19 years: 9 mg

Iron supplements can be helpful when people find it difficult to take in enough iron through only dietary measures such as in a plant-based diet. It is better to try to consume enough in the diet alone by removing or reducing factors that may hinder iron absorption and consuming protein-rich foods. This is because many protein-rich foods also contain a range of other beneficial nutrients that work together to support overall health.

What to Know about Iron Deficiency Anemia?

Iron deficiency anemia is a condition where there are too few red blood cells in the body due to a shortage of it. The body uses it to produce red blood cells, which transport oxygen around the body. Without enough it, there may be too few healthy red blood cells to carry sufficient oxygen to satisfy the body needs. The results of this situation is called deficiency anemia which can leave a person feeling extremely tired and out of birth.

What is Anemia?

Anemia is a blood condition characterized by a lack of healthy red blood cells or hemoglobin. Hemoglobin is the part of the red blood cells that binds to oxygen. When the body does not have enough hemoglobin circulating, not enough oxygen gateways to all parts of the body either. As a result organs and tissues may not function properly and a person may feel fatigued. The deficiency anemia occurs when the body does not have enough it to produce the hemoglobin it needs.

What are the Causes of Anemia?

Iron deficiency anemia relates directly to a lack of it in the body. The cause of the iron deficiency varies however. Some common causes include:

  • Poor diet
  • Blood loss
  • A decreased ability to absorb iron
  • Pregnancy

What are the Symptoms of Anemia?

Iron deficiency anemia often takes a long time to develop. People may not know they have it until the symptoms are severe. In some cases the deficiency may improve with no intervention as a person’s situation changes such as after a woman has given birth. However if a person has any symptoms of it deficiency anemia they should talk to their doctor. A person with an IT deficiency can have some of the following symptoms. Such as:

  • General weakness
  • Dizziness or lightheadedness
  • Extreme fatigue
  • Fast heartbeat
  • Easily broken and brittle nails
  • Paler than normal skin
  • Asthma
  • Chest pain
  • Headaches
  • Cold hands and feet
  • Shortness of breath
  • Soreness or inflammation of the tongue
  • Cravings for non-nutritive things such as dirt, starch, or ice
  • Poor appetite especially in children

What are the Risk Factors of Anemia?

Some groups of people have a higher risk of developing deficiency anemia. Some groups that are risk include:

  • Vegetarians
  • Women
  • Blood donors
  • Infants and children

What is the Diagnosis of Anemia?

Only a doctor can diagnose iron deficiency anemia. It is important for a person to seek advice from a medical professional if they have noticeable symptoms. It is likely that a doctor will begin the exam by asking questions about a person’s general health. They may examine the skin tone, the fingernails, and under the eyelids to look for physical signs of iron deficiency anemia. However, since iron deficiency anemia doesn’t always have visible symptoms a blood test will probably be needed. A doctor will check the blood for the following:

  • The hematocrit or the percentage red blood cells in the total volume of the blood
  • Size and color of the red blood cells looking especially for smaller pale cells
  • Low ferritin levels where a shortage of this protein indicates poor iron storage in the blood
  • Lower hemoglobin levels that are associated with iron deficiency

A doctor may ask further questions or run additional tests to help determine if the deficiency anemia is the result of an undiagnosed underlying condition. These tests may vary depending on other symptoms a person describes. For example, someone experiencing pain during digestion may require a colonoscopy to see if a gastrointestinal disease is the cause of the iron deficiency.

What are the Complications of Anemia?

In milder cases of it deficiency anemia a person is unlikely to have more than the normal symptoms described above. However, additional complications can occur if the iron deficiency anemia is left untreated. Possible complications include:

  • Slow growth and developmental delays in children and infants
  • Heart problems including heart failure or an enlarged heart due to it compensating or lack of oxygen
  • Pregnancy complications including low birth weights and an increased risk for temperature birth

How to Get More Iron from the Diet?

To get more it from the diet people should consume foods that are rich in it such as liver, tofu, and spinach alongside foods that help the body absorb it, for instance, those containing vitamin C. It plays a critical role in transporting oxygen around the body. Getting more of it into the diet can help prevent deficiency anemia and improve general health. The body needs it to help it carry out many vital processes such as energy production, growth, development, and the synthesis of hormones. It also helps to keep the immune system healthy. In this article we look at the different types of it, which foods are rich in it and how to increase absorption of it. We also cover recommended daily allowance (RDA) the symptoms and risk factors for it deficiency and whether someone can have too much in their body.

Iron Rich Foods of Iron:

Foods that are rich in heme and nonheme iron include:

  • Liver
  • Lean and meat
  • Chicken
  • Seafood, including oysters
  • Lentils and beans
  • Tofu
  • Fortified breakfast cereals
  • Dried fruits such as prunes, figs, and apricots
  • Nuts
  • Pistachios 
  • Seeds
  • Eggs
  • Soya
  • Walnuts
  • Molasses

Dark green leafy vegetables are an excellent source of it including:

  • Spinach
  • Kale
  • Seaweed
  • Watercress
  • Broccoli
  • Asparagus
  • Parsley

How to Increase Iron Absorption?

Certain foods and drinks can affect its absorption. Such as:

  • Tannins
  • Vitamin C
  • Phytates

What are the Symptoms of Iron Deficiency?

Generally, there is a healthy balance between the supply of it through the diet and demand for it from the body. However, if demand outstrips supply, the body will start to use up iron stored in the liver which can lead to the deficiency. When the body has used  up, it is unable to produce hemoglobin. This is called iron deficiency anemia. A doctor can diagnose anemia using a blood test to measure serum ferritin and hemoglobin levels. The World Health Organization (WHO) classifies mild anemia as having a hemoglobin level of:

  • Less than 119 grams per liter for adult females
  • Less than 129 g/l for adult males

Symptoms of iron deficiency can occur even before a person has anemia and can include:

  • Fatigue
  • Dizziness
  • Pale skin color
  • Hair loss
  • Irritability
  • Weakness
  • Pica, a craving to eat dirt, brick or sand
  • Restless leg syndrome
  • Brittle or grooved nails
  • Anyone who experiences any of these symptoms should see a doctor.

What are the Risk Factors of Iron Deficiency?

Iron deficiency anemia is the most common nutritional deficiency worldwide. Risk factors for iron deficiency include:

  • Females of childbearing age
  • Being pregnant
  • Poor diet
  • Donating blood frequently
  • Infants and children especially those born prematurely or experiencing a growth spurt
  • Gastrointestinal disorders
  • Old age
  • Vegetarians and vegans


What are the 10 main functions of iron?

  • It helps oxygenate the blood
  • It helps convert blood sugar to energy
  • It boosts the immune system
  • It aids cognitive function
  • It supports healthy skin, hairs, and nails
  • Reduce tiredness and fatigue
  • Improve both mental and physical performance
  • Helps with athletic performance
  • Contributes to good health and vitality
  • Supports vaccine efficacy

What are the 5 benefits of iron?

  • Reduces the tiredness and fatigue
  • Contributes to the normal formation of red blood cells hemoglobin function to carry oxygen around the body to support body function
  • Supports normal cognitive function
  • Improves physical performance while contributing to muscle growth and body development
  • Assists with a healthy pregnancy

Why is iron most important?

Is essential in the production of steel, it is also essential to human life. About 70% of the iron in your body can be found in a protein in red blood cells called hemoglobin. It is essential in making hemoglobin a protein in red blood cells. These red blood cells help carry oxygen throughout your body.

Which food contains iron?

  • Meat, poultry and fish
  • Eggs
  • Beans, peas, lentils, tofu
  • Some vegetables such as spinach and beets
  • Whole grain such as quinoa, whole oats, and whole grain bread
  • Nuts, seeds and some dried fruit like raisins

What is iron in biology?

It is a component of hemoglobin, an oxygen carrier that transports oxygen from the lungs to the peripheral tissues and then carries carbon dioxide back to the lungs. Likewise, it is a constituent of myoglobin, an oxygen storage protein that provides oxygen to muscle tissue.

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