Iron: Benefits, Food Sources and Risks

In nutrition, iron is a mineral the body needs to make red blood cells, proteins, and enzymes; and for the control of cell growth and cell specialization. Iron is found in some foods, including red meats, fish, poultry, lentils, and beans.

Iron is a mineral that the body needs for growth and development. Your body uses iron to make hemoglobin, a protein in red blood cells that carries oxygen from the lungs to all parts of the body, and myoglobin, a protein that provides oxygen to muscles. Your body also needs iron to make some hormones. Iron also has a role in a variety of other important processes in the body.

Iron supplements play a vital role in treating anemia (low levels of healthy RBCs), particularly iron deficiency anemia (IDA). Most people get all the iron they need from their diets. However, some may be prone to iron deficiency. Iron deficiency is the most common cause of anemia, occurring in 5% of women and 2% of men.

Recommended Intake

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


  • 0 to 6 months: 0.27 milligrams (mg)
  • 7 to 12 months: 11 mg


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


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


  • 9 to 13 years: 8 mg
  • 14 to 18 years: 15 mg
  • 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 iron-rich foods.

This is because many iron-rich foods also contain a range of other beneficial nutrients that work together to support overall health.


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 iron, the type found in plants, requires that the body take multiple steps to absorb it. Plant-based sources of iron include beans, nuts, soy, vegetables, and fortified grains.

The bioavailability of heme iron from animal sources can be up to 40 percent. Non-heme iron from plant-based sources, however, has a bioavailability of between 2 and 20 %. For this reason, the RDA for vegetarians is 1.8 times higher than for those who eat meat to make up for the lower absorption level from plant-based foods.

Consuming vitamin-C-rich foods alongside non-heme sources of iron can dramatically increase iron absorption.

When following a vegetarian diet, it is also important to consider components of food and medications that block or reduce iron absorption, such as:

  • proton pump inhibitors and omeprazole, used 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
  • phosphates in carbonated beverages, such as soda
  • phytates in beans and grains


Iron has a 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 components of the diet
  • gastrointestinal health
  • use of medications or supplements
  • a person’s overall iron status
  • presence of iron promoters, such as vitamin C

In many countries, wheat products and infant formulas are fortified with iron.

Food Sources

  • Canned clams
  • Fortified, plain, dry cereal oats
  • White beans
  • Dark chocolate
  • Cooked Pacific oysters
  • Cooked spinach
  • Beef liver
  • Boiled and drained lentils
  • Firm tofu
  • Boiled and drained chickpeas
  • Canned, stewed tomatoes
  • Lean, ground beef
  • Medium baked potato
  • Roasted cashew nuts

Calcium can slow both heme and non-heme iron absorption. In most cases, a typical varied, Western-style diet is considered balanced in terms of enhancers and inhibitors of iron absorption.

How to Get More Iron From Your Food?

Some foods can help your body absorb iron from iron-rich foods; others can hinder it. To absorb the most iron from the foods you eat, avoid drinking coffee or tea or consuming calcium-rich foods or drinks with meals containing iron-rich foods. Calcium itself can interfere. To improve your absorption of iron, eat it along with a good source of vitamin C, such as orange juice, broccoli, or strawberries or eat nonheme iron foods with a food from the meat, fish, and poultry group.

If you have trouble getting enough iron from food sources, you may need an iron supplement. But speak to your health care provider about the proper dosage first and follow their instructions carefully. Because very little iron is excreted from the body, iron can accumulate in body tissues and organs when the normal storage sites the liver, spleen, and bone marrow are full. Although iron toxicity from food sources is rare, deadly overdoses are possible with supplements.


In adults, doses for oral iron supplementation can be as high as 60 to 120 mg of elemental iron per day. These doses typically apply to women who are pregnant and severely iron-deficient. An upset stomach is a common side effect of iron supplementation, so dividing doses throughout the day may help.

More recently, scientists have begun investigating the possible role of excess iron in the development and progression of neurological diseases, such as Alzheimer’s disease, and Parkinson’s disease. Iron may also have a direct damaging role in brain injury that results from bleeding within the brain. Research in mice has shown that high iron states increase the risk of osteoarthritis.

Iron supplements can decrease the availability of several medications, including levodopa, which is used to treat restless leg syndrome and Parkinson’s disease and levothyroxine, which is used to treat a low-functioning thyroid.

Adults with a healthy digestive system have a very low risk of iron overload from dietary sources.

Discuss taking an iron supplement with a physician or healthcare practitioner, as some of the signs of iron overload can resemble those of iron deficiency. Excess iron can be dangerous, and iron supplements are not recommended except in cases of diagnosed deficiency, or where a person is at high risk of developing iron deficiency.

It is preferable to achieve optimal iron intake and status through the diet rather than supplements. This can help minimize the risk of iron overdose and ensure a good intake of the other nutrients found alongside iron in foods.