Understanding Iron

What is Iron?

Iron is an essential mineral that our bodies need to grow, develop and function properly. On the periodic table you’ll find it listed as the symbol Fe. Since our bodies don’t naturally produce iron, we must rely on foods and supplementation to meet our daily requirement. Iron helps blood carry oxygen from our lungs throughout our bodies; supports our immune system and brain development; and regulates our temperature, metabolism and work performance. 

About 90 percent of the iron in our body is conserved and reused every day. Men are able to naturally store more iron than women. Dietary iron ideally supplies enough iron to meet the 10 percent gap that our bodies lose each day, if not a deficiency will result in both men and women.

Why Do Our Bodies Need It? 1

Once our cells have absorbed iron from food, our bodies use it to make hemoglobin and myoglobin. These proteins help carry and store oxygen in the body. Hemoglobin is found in red blood cells and myoglobin is found in muscles. Iron is also part of many other proteins and enzymes that assist in food digestion as well as other important reactions that occur within our bodies.

Without an adequate supply of iron, the body and its organs cannot function properly and may make you feel “under the weather.” An iron deficiency can impair mental function and memory, lead to a rapid or irregular heartbeat, cause fatigue and weaken the immune system.

How Much Iron is Enough? 2

Men, women and children require different intakes of iron to keep their bodies healthy. The Institute of Medicine of the National Academy of Sciences developed the Recommended Dietary Allowance (RDA) to outline the average daily intake of elemental iron that is sufficient to meet the nutrient requirements of nearly all (97–98 percent) healthy individuals in various age and gender groups. 

AGE (years) Males (mg/day) Females (mg/day) Pregnancy (mg/day) Lactation (mg/day)
9-13 8 8 N/A N/A
14-18 11 15 27 10
19-50 8 18 27 9
51+ 8 8 N/A N/A

Talk to your pediatrician about the iron needs of infants. 

Iron-rich Foods 3

Non-heme iron represents the majority of iron we consume in our diets and is the type of iron found in most supplements. You’ll find non-heme iron in the greatest quantities in grains, seeds and legumes such as:

  • Pumpkin seeds
  • Whole grains
  • Dried beans like kidney, black and lentils
  • Enriched rice

Other great sources of non-heme iron include:

  • Nuts
  • Dark-green vegetables
  • Fortified foods such as breakfast cereal

Click here to view the number of milligrams of iron in foods to meet your Recommended Dietary Allowance.

Non-heme iron is different from heme iron because it has to undergo chemical changes as part of digestion, making it more difficult to absorb. Foods that are rich in vitamin C, such as fruits and vegetables, aid your body with absorbing non-heme iron when eaten at the same meal.

Many substances can reduce the amount of non-heme iron we absorb, including:

  • Coffee or tea
  • Dairy
  • Fiber  
  • Eggs
  • Some types of chocolate

Vitamin C aids in the absorption of iron in plant foods (especially important for vegetarians). Calcium can impair the absorption, so people who need more iron should consult their doctor to make sure they are getting the right balance of calcium and iron. 

Heme Iron

Heme iron is the best source of iron for people who are iron deficient because it is easily absorbed by the body. Unlike non-heme iron, heme iron can be absorbed as is, making the process more efficient. You’ll find the highest concentration of heme iron in meat, especially red meat because the iron has already been converted to heme form. 

Patients should talk to their health care provider before making any changes to their diet.

Absorption of Iron 4


For more details on the absorption of iron, click here.

Disclaimer: The information on this site is for informational purposes only and not intended to provide medical advice. You should direct all questions about your health to your health care provider.