Iron Supplements That Don't Cause Nausea

Iron is an essential component of human nutrition. Although two-thirds of your body's iron stores are found within your red blood cells, every cell in your body contains at least some iron. According to the World Health Organization, iron deficiency is the most common and widespread nutritional disorder in the world, affecting people in both industrialized and developing countries. If your doctor has instructed you to take iron supplements, you may be wondering if they all cause nausea or constipation.

Iron Functions

One of iron's most important functions in animals is oxygen transport. As part of the hemoglobin molecule in your red blood cells, iron carries oxygen to every tissue and cell in your body. Iron is also an important constituent of myoglobin, a hemoglobin-like molecule in your muscles that helps them utilize oxygen more efficiently. The Linus Pauling Institute at Oregon State University reports that iron-containing enzymes are essential for cellular energy production, detoxification processes and normal immune function. Iron deficiency interferes with all of these metabolic activities.

Iron Deficiency

The most notable complication of iron deficiency is impairment of your body's ability to produce red blood cells. This condition, known as iron-deficiency anemia, is characterized by fatigue, poor exercise tolerance, dizziness, decreased mental function, muscle weakness and racing heart. Some medical conditions, such as coronary artery disease, are worsened by iron deficiency. In pregnant women, iron deficiency increases your risk for preterm delivery, low birth-weight infants and stillbirth. In growing children, learning disabilities are associated with iron deficiency. Therefore, it is essential to take iron supplements if you are iron deficient.

Sources

Iron is found in both plant and animal foods, although the iron from animal sources -- called heme iron -- is more efficiently absorbed from your intestine. Red meats, fish, liver, egg yolks, whole grains, legumes, nuts, seeds, green vegetables and dried fruits are all good sources of iron. However, if you are iron-deficient, you may not be able to acquire enough iron from your diet, and your physician will recommend an iron supplement. Since it can take 6 weeks or more to benefit from iron supplementation, you need a supplement that you can tolerate.

Approaches

Iron sulfate is the most commonly recommended oral supplement for treating or preventing iron deficiency. It is also the least well-absorbed, which increases your risk for nausea and constipation. Ferrous gluconate and fumarate are more readily absorbed, and you may find they cause less nausea. Hydrolyzed chelates of iron -- iron aspartate or ferrous succinate, for example -- are probably the most easily absorbed and the least likely to cause gastrointestinal upset. If possible, split your iron into two or three daily doses or try a liquid form if capsules continue to cause problems. Take your iron with 50 to 100 mg of vitamin C to improve its absorption.

Dosage

Recommended dietary allowances for iron -- the amounts needed to prevent deficiency in healthy people -- range from 0.27 mg daily for infants to 27 mg for pregnant women. If you are iron-deficient, you will need to take higher doses. Since the absorption of different supplements varies significantly, your doctor might prescribe 325 mg of ferrous sulfate, fumarate or gluconate 2 to 3 times daily. In contrast, you may only need one or two 50 mg doses of a chelated iron supplement to accomplish the same purpose. Follow your physician's instructions for the iron supplement that works best for you.