Iron is a mineral that plays a vital role in the transport of oxygen through the blood and to all the body’s tissues. Not having enough iron can lead to iron deficiency anemia, which could lead to a heart attack or stroke in extreme cases. 

Conversely, too much iron has also been associated in some studies with an increased risk of heart attack and other harmful health consequences. However, further research is needed to validate this claim. Therefore, all people (particularly women) are strongly encouraged to consult their physician about how much iron they should be taking. As with all vitamins and minerals, moderation is the key.

Iron is one of the essential minerals required by the body. It plays a key role in the function of hemoglobin, which is the pigment in red blood cells that carries oxygen to all the body’s tissues. Iron is also needed by certain enzymes that facilitate chemical reactions in the body. Without adequate iron, the body’s ability to carry oxygen from the lungs to the other body cells decreases. This lack of oxygen leads to low production of energy, causing fatigue. This condition is called iron–deficiency anemia.

Iron deficiency may be caused by not getting enough iron through diet or because the body is unable to absorb the iron found in foods. Additionally, iron deficiency can occur due to increased losses of iron (e.g. bleeding) or due to increased needs for iron (e.g. pregnancy, growth spurts).

Although anyone can develop iron-deficiency anemia, it is most commonly seen in young women. This may be due to menstrual flow and lack of iron-rich foods in the diet. The most common signs and symptoms of anemia are fatigue, paleness, rapid heart beat, brittle nails, headaches, shortness of breath and cold hands and feet.

If a routine blood test, called a complete blood count (CBC) finds any indications of too little iron, the physician will order additional blood tests to measure:

Too much of any vitamin or mineral can be harmful. Excess iron levels have been linked to an increased risk of colon cancer and other serious medical concerns. As discussed below, high iron levels have also been linked in some studies to heart disease, although the link has not yet been proven and remains highly controversial.

Since the 1990s, studies have been conducted to find a link between excess iron levels in the body and heart attacks and stroke. However, so far, the results inconclusive and unreliable. Further research is needed to find a clear association between iron levels, heart attack and stroke.

For example, one study found that men with high levels of iron stored in their body had almost three times the number of heart attacks than men with lower levels of iron. On the other hand, some studies examining the link between high iron levels and atherosclerosis (hardening of the arteries), a strong indicator for heart disease, have yielded contradictory results.

To explain the possible link, some experts suggest that high amounts of iron contribute to oxidation – the harmful process by which LDL (“bad”) cholesterol becomes fatty plaque in the arteries. Other experts believe that high iron levels contribute to the production of oxygen free radicals, which promote the buildup of plaque in the arteries. A 2000 study suggested that high iron levels are associated with greater stroke damage because of their effect on these oxygen free radicals. Because antioxidants such as vitamins A, C, E and selenium counteract both oxidation and oxygen free radicals, it has been further proposed that people who take supplements that contain antioxidants may counter this potentially harmful effect of iron. 

The link between high iron levels and heart disease is strengthened by the fact that women are at a lower risk of heart disease before menopause, when they are having  regular menstrual cycles. After menopause, when menstruation ends, women’s risk of heart disease increases along with the levels of iron in their bloodstream. However, some scientists suggest that the increased risk of heart disease following menopause has more to do with a decrease in estrogen (which is though to protect the body against heart disease) than an increase in iron levels.

It is important to note that, despite the apparent risks of high iron levels, the American Heart Association (AHA) does not recommend that people lower the amount of iron they receive in their diet. Instead, patients who are concerned about their iron levels should consult their physician about the need to lower iron levels.        

The most significant risk to the heart from low iron levels is anemia. When the body does not receive enough iron, its tissues receive less oxygen and iron-deficiency anemia may develop. Anemia may cause several heart-related problems. For example, people with anemia and coronary artery disease are more likely to experience angina. Anemia can also cause arrhythmia as the heart works harder to pump enough oxygen around the body. Both angina and arrhythmia are known to increase the risk of a heart attack.

Additionally, severe cases of iron deficiency could lead to a serious lack of oxygen-rich blood to the heart and brain, resulting in a heart attack or stroke. People at higher risk for these life-threatening events are those with coronary artery disease or carotid artery disease.

As many as 25 to 60 percent of patients with heart failure also have anemia, which tends to worsen as the heart failure progresses. Furthermore, severe anemia could actually cause heart failure because the heart works harder to circulate a lower number of red blood cells through the body. Studies have suggested that treating anemia in heart failure patients may improve the heart’s condition and allow patients to spend fewer days in the hospital.

According to the National Institutes of Health, 20 percent of women and 3 percent of men are deficient in iron. Additionally, as many as 50 percent of pregnant women are iron deficient. Some people with this condition may not have any symptoms, and others may notice signs such as paleness and symptoms such as fatigue and irritability. People who are concerned about their iron levels should consult their physician before taking any supplements.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. You may wish to ask your doctor the following questions about iron:

1. What are signs that I may need additional iron?
   
   
2. Are my iron levels affecting my heart health?
   
   
3. Is it possible to take too much iron? If so, how will I know if I am taking too much?
   
   
4. Should I have blood work done before I begin taking iron supplements?
   
   
5. Do I need to have follow-up blood work done once I begin taking an iron supplement?
   
   
6. Does my my age, gender or lifestyle increase my risk for anemia?
   
   
7. What is the difference between prescription and over-the-counter iron?
   
   
8. Do I currently take any medications that might make it dangerous to take iron?
   
   
9. Could taking iron affect my pregnancy in any way?