Iron and Iron Deficiency

Take the Blood Disorders Quiz

Quick GuideThe 14 Most Common Causes of Fatigue

The 14 Most Common Causes of Fatigue

What causes iron deficiency?

Iron deficiency has many causes. (See table below for a summary). These causes fall into two main categories:

  1. Increased iron needs

Many common conditions can cause people to need additional iron:

  • Because of their rapid growth, infants and toddlers need more iron than older children. Sometimes it can be hard for them to get enough iron from their normal diet.
  • Women who are pregnant have higher iron needs. To get enough, most women must take an iron supplement as recommended by their healthcare provider.
  • When people lose blood, they also lose iron. They need extra iron to replace what they have lost. Increased blood loss can occur with heavy menstrual periods, frequent blood donation, as well as with some stomach and intestinal conditions (food sensitivity, hookworms.)
  1. Decreased iron intake or absorption (not enough iron taken into the body)

The amount of iron absorbed from the diet depends on many factors:

  • Iron from meat, poultry, and fish (i.e., heme iron) is absorbed two to three times more efficiently than iron from plants (i.e., non-heme iron).
  • The amount of iron absorbed from plant foods (non-heme iron) depends on the other types of foods eaten at the same meal.
  • Foods containing heme iron (meat, poultry, and fish) enhance iron absorption from foods that contain non-heme iron (e.g., fortified cereals, some beans, and spinach).
  • Foods containing vitamin C (see Dietary Sources of vitamin C) also enhance non-heme iron absorption when eaten at the same meal.
  • Substances (such as polyphenols, phytates, or calcium) that are part of some foods or drinks such as tea, coffee, whole grains, legumes and milk or dairy products can decrease the amount of non-heme iron absorbed at a meal. Calcium can also decrease the amount heme-iron absorbed at a meal. However, for healthy individuals who consume a varied diet that conforms to the Dietary Guidelines for Americans, the amount of iron inhibition from these substances is usually not of concern.
  • Vegetarian diets are low in heme iron, but careful meal planning can help increase the amount of iron absorbed.
  • Some other factors (such as taking antacids beyond the recommended dose or medicine used to treat peptic ulcer disease and acid reflux) can reduce the amount of acid in the stomach and the iron absorbed and cause iron deficiency.
Increased Iron Needs Decreased Iron Intake and Absorption
  • Rapid growth
  • Pregnancy
  • Blood loss
    • Heavy menstrual periods
    • Frequent blood donation
    • Some stomach and intestinal conditions (food sensitivity, hookworms)
  • Lack of heme iron sources in the diet (e.g., vegetarian diets)
  • Low absorption
    • Taking antacids beyond the recommended dose or medicine used to treat peptic ulcer disease and acid reflux can reduce the amount of iron absorbed in the stomach.

Subscribe to MedicineNet's Newsletters

Get the latest health and medical information delivered direct to your inbox!

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

  • Iron Deficiency - Signs and Symptoms

    What were the signs and symptoms associated with your iron deficiency?

    Post View 14 Comments
  • Iron Deficiency - Detection

    How was your iron deficiency detected?

    Post View 6 Comments
  • Iron Deficiency - Treatment

    If you have an iron deficiency, what type of treatment or supplements do you take?

    Post View 1 Comment
  • Iron Deficiency - Pregnant Women

    If you are pregnant with an iron deficiency, please discuss how it was detected and is being treated.

  • Iron Deficiency - Diet

    Which iron-rich foods have you added to your diet? Have you noticed a difference in the way you feel?


Health Solutions From Our Sponsors