Iron supplements, also known as “iron pills,” are commonly used to treat anemia (a condition characterized by the lack of healthy red blood cells or hemoglobin).
Iron plays a key role in making red blood cells that transport oxygen molecules throughout the body. Iron is also needed to metabolize the nutrients we eat and convert them into energy. Moreover, it contributes to the transmission of nerve signals to and from the brain.
While you will generally get enough iron from the foods you eat, there may be times when you may experience an iron deficiency. This commonly occurs during pregnancy or heavy menstruation.
There are certain groups vulnerable to iron deficiency, including preterm infants, young children, teenage girls, and individuals with chronic heart failure, Crohn’s disease, celiac disease, or ulcerative colitis. Iron supplements are also commonly prescribed to women of childbearing age to help prevent anemia.1
Iron supplements are used to treat iron deficiency and iron-deficiency anemia. They are not typically used to treat other types of anemia (such as vitamin-deficiency anemia, hemolytic anemia, aplastic anemia, or anemia of chronic disease) unless iron deficiency is diagnosed. The response to oral iron supplements can vary by the underlying cause.
Iron deficiency, also known as sideropenia, is the state in which your body lacks the iron needed to maintain normal function. Iron deficiency is common in the developing world where more than a quarter of the population may be affected (mostly due to poverty and the lack of nutrition). While this is less common in the United States, it still does occur. Iron deficiency can also occur due to physiological changes that leave you at a deficit. Iron deficiency can occur in children, for example, because their bodies grow so quickly. Starting at adolescence, a woman’s iron need will increase due to her monthly menstrual cycle.
Iron deficiency anemia is a common type of anemia — a condition in which blood lacks adequate healthy red blood cells. Red blood cells carry oxygen to the body’s tissues.
As the name implies, iron deficiency anemia is due to insufficient iron. Without enough iron, your body can’t produce enough of a substance in red blood cells that enables them to carry oxygen (hemoglobin). As a result, iron deficiency anemia may leave you tired and short of breath. You can usually correct iron deficiency anemia with iron supplementation. Sometimes additional tests or treatments for iron deficiency anemia are necessary, especially if your doctor suspects that you’re bleeding internally.
Initially, iron deficiency anemia can be so mild that it goes unnoticed. But as the body becomes more deficient in iron and anemia worsens, the signs and symptoms intensify.
Iron deficiency anemia signs and symptoms may include:
- Extreme fatigue
- Pale skin
- Chest pain, fast heartbeat or shortness of breath
- Headache, dizziness or lightheadedness
- Cold hands and feet
- Inflammation or soreness of your tongue
- Brittle nails
- Unusual cravings for non-nutritive substances, such as ice, dirt or starch
- Poor appetite, especially in infants and children with iron deficiency anemia
Iron deficiency anemia occurs when your body doesn’t have enough iron to produce hemoglobin. Hemoglobin is the part of red blood cells that gives blood its red color and enables the red blood cells to carry oxygenated blood throughout your body.
If you aren’t consuming enough iron, or if you’re losing too much iron, your body can’t produce enough hemoglobin, and iron deficiency anemia will eventually develop.
Causes of iron deficiency anemia include:
- Blood loss. Blood contains iron within red blood cells. So if you lose blood, you lose some iron. Women with heavy periods are at risk of iron deficiency anemia because they lose blood during menstruation. Slow, chronic blood loss within the body — such as from a peptic ulcer, a hiatal hernia, a colon polyp or colorectal cancer — can cause iron deficiency anemia. Gastrointestinal bleeding can result from regular use of some over-the-counter pain relievers, especially aspirin.
- A lack of iron in your diet. Your body regularly gets iron from the foods you eat. If you consume too little iron, over time your body can become iron deficient. Examples of iron-rich foods include meat, eggs, leafy green vegetables and iron-fortified foods. For proper growth and development, infants and children need iron from their diets, too.
- An inability to absorb iron. Iron from food is absorbed into your bloodstream in your small intestine. An intestinal disorder, such as celiac disease, which affects your intestine’s ability to absorb nutrients from digested food, can lead to iron deficiency anemia. If part of your small intestine has been bypassed or removed surgically, that may affect your ability to absorb iron and other nutrients.
- Pregnancy. Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a source of hemoglobin for the growing fetus.
These groups of people may have an increased risk of iron deficiency anemia:
- Women. Because women lose blood during menstruation, women in general are at greater risk of iron deficiency anemia.
- Infants and children. Infants, especially those who were low birth weight or born prematurely, who don’t get enough iron from breast milk or formula may be at risk of iron deficiency. Children need extra iron during growth spurts. If your child isn’t eating a healthy, varied diet, he or she may be at risk of anemia.
- Vegetarians. People who don’t eat meat may have a greater risk of iron deficiency anemia if they don’t eat other iron-rich foods.
- Frequent blood donors. People who routinely donate blood may have an increased risk of iron deficiency anemia since blood donation can deplete iron stores. Low hemoglobin related to blood donation may be a temporary problem remedied by eating more iron-rich foods. If you’re told that you can’t donate blood because of low hemoglobin, ask your doctor whether you should be concerned.
Mild iron deficiency anemia usually doesn’t cause complications. However, left untreated, iron deficiency anemia can become severe and lead to health problems, including the following:
- Heart problems. Iron deficiency anemia may lead to a rapid or irregular heartbeat. Your heart must pump more blood to compensate for the lack of oxygen carried in your blood when you’re anemic. This can lead to an enlarged heart or heart failure.
- Problems during pregnancy. In pregnant women, severe iron deficiency anemia has been linked to premature births and low birth weight babies. But the condition is preventable in pregnant women who receive iron supplements as part of their prenatal care.
- Growth problems. In infants and children, severe iron deficiency can lead to anemia as well as delayed growth and development. Additionally, iron deficiency anemia is associated with an increased susceptibility to infections.
You can reduce your risk of iron deficiency anemia by choosing iron-rich foods.
Choose iron-rich foods
Foods rich in iron include:
- Red meat, pork and poultry
- Dark green leafy vegetables, such as spinach
- Dried fruit, such as raisins and apricots
- Iron-fortified cereals, breads and pastas
Your body absorbs more iron from meat than it does from other sources. If you choose to not eat meat, you may need to increase your intake of iron-rich, plant-based foods to absorb the same amount of iron as does someone who eats meat.
Choose foods containing vitamin C to enhance iron absorption
You can enhance your body’s absorption of iron by drinking citrus juice or eating other foods rich in vitamin C at the same time that you eat high-iron foods. Vitamin C in citrus juices, like orange juice, helps your body to better absorb dietary iron.
Vitamin C is also found in:
- Leafy greens
Preventing iron deficiency anemia in infants
To prevent iron deficiency anemia in infants, feed your baby breast milk or iron-fortified formula for the first year. Cow’s milk isn’t a good source of iron for babies and isn’t recommended for infants under 1 year. After age 6 months, start feeding your baby iron-fortified cereals or pureed meats at least twice a day to boost iron intake. After one year, be sure children don’t drink more than 20 ounces (591 milliliters) of milk a day. Too much milk often takes the place of other foods, including those that are rich in iron.
Products & Services
Whatever the cause, iron deficiency can lead to iron-deficiency anemia if left untreated. Iron supplements may not only be used to treat a deficiency but prevent it from occurring in the first place. Iron supplements are often provided to people at high risk of a deficiency. These include pregnant women, people on dialysis, or those with inflammatory bowel disease or thyroid disease.
Doing so can help prevent or treat many of the common symptoms of iron deficiency, including:2
Possible Side Effects
Iron supplements are generally safe and well-tolerated if taken at the recommended dose. The supplement may cause side effects in some people, including upset stomach, nausea, diarrhea, faintness, and vomiting. Dark stools are also common.Taking the supplement with food can usually alleviate many of the symptoms.4
Iron supplements can cause constipation during pregnancy. Adding fiber to your diet or using a stool softener can usually help manage the symptom. To reduce the risk of side effects, start with a lower dose and gradually increase the dose as tolerated.
Taking too much iron can lead to iron overload. Extra iron in your blood can be toxic the liver, heart, and pancreas and may cause damage to the joints, as well.
Excessive doses of iron can lead to iron poisoning. Even a single high dose (60 milligrams per kilogram of body weight or more) can lead to death. The symptoms of iron poisoning usually become apparent within six to 24 hours of a dose and may include severe vomiting, diarrhea, and abdominal pain, oftentimes with bloody vomit or stools (especially in children).5
Taking iron supplements containing 25 milligrams or more of elemental iron can affect the absorption of zinc and lead to a zinc deficiency.1 (Elemental iron is not the same thing as the iron supplement dose. Check the product label or speak with your pharmacist who can show you the difference.)
Iron supplements may also interact with the following drugs:
- Levodopa used to treat Parkinson’s disease
- Proton pump inhibitors, including Prevacid (lansoprazole) and Prilosec (omeprazole)
- Synthroid (levothyroxine) used to treat thyroid disease
In some cases, separating the doses by two hours may be all that is needed to avoid interactions. In other cases, a dose adjustment may be needed. Speak with your healthcare provider if you intend to use iron supplements and take these or any other chronic medication.1
Dosage and Preparation
Iron supplements are typically formulated as tablets or capsules. The dose can vary based on the level of your deficiency as well as the underlying cause. Your healthcare provider will recommend a dose based largely on the Recommended Dietary Allowance (RDA) for iron for your age, sex, and pregnancy status, as follows:1
- Birth to six months: 0.27 mg
- Seven to 12 months: 11 mg
- One to three years: 7 mg
- Four to eight years: 10 mg
- Nine to 14 years: 8 mg
- Boys 14 to 18 years: 11 mg
- Girls 14 to 18: 15 mg
- Men 19 to 50: 8 mg
- Women 19 to 50: 18 mg
- Pregnant women 14 to 18: 27 mg
- Breastfeeding women 14 to 18: 10 mg
- Pregnant women 19 to 50: 27 mg
- Breastfeeding women 19 to 50: 9 mg
Drink a full glass of water or orange juice with each dose. The vitamin C in orange juice is said to boost absorption.6 The water helps disperse the iron for better absorption.
When used to treat iron-deficiency anemia, the duration of therapy may be as long as six months. This requires a commitment on your part. Once started, you would need to continue treatment even if you feel better and no longer have symptoms.
What to Look For
Vitamin and mineral supplements are not subject to rigorous testing in the United States and can vary from one brand to the next. To ensure quality and safety, opt for supplements that have been tested and approved by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International.
Iron supplements can degrade when exposed to excessive temperatures and UV radiation. To avoid this, keep the supplements in their original light-resistance container and store in a dry, cool room. Always check the use-by date and discard of any expired, discolored, or damaged supplements.