Ironing out the myths about iron

Sometime ago, we received an e-mail inquiring about iron and what it does (and does not do) for the body.

The Healthy Options team headed by dynamo Romy Sia did some research and came up with some answers to oft-asked questions about iron. So, here’s everything you’ve always wanted to know about iron but were probably too tired (due to iron deficiency) to ask:

Exactly what does iron do?

Iron is part of hemoglobin, the oxygen-carrying component of the blood. Iron-deficient people tire easily partly because their bodies are starved for oxygen. Iron is also part of myoglobin, which helps muscle cells store oxygen. Without enough iron, ATP (the fuel the body runs on) cannot be properly synthesized. As a result, some iron-deficient people become fatigued even when their hemoglobin levels are normal (that is, when they are not anemic).

Although iron is part of the antioxidantenzyme catalase, it is not generally considered an antioxidant because too much iron can cause oxidative damage.

Where is it found?

The most absorbable form of iron (called heme iron) is found in oysters, meat, poultry, and fish. Non-heme iron is also found in these foods, as well as in dried fruit, molasses, leafy green vegetables, wine, and iron supplements. Acidic foods (like tomato sauce) cooked in an iron pan can also be a source of dietary iron.

Who is likely to be iron deficient?

Vegetarians eat less iron than non-vegetarians, and the iron they eat is somewhat less absorbable. As a result, vegetarians are more likely to have reduced iron stores. However, iron deficiency is not usually caused by a lack of iron in the diet alone. An underlying cause, such as iron loss in menstrual blood, often exists.

Also more likely to become deficient are pregnant women, marathon runners, people who take aspirin, and those who have parasitic infections, hemorrhoids, ulcers, ulcerative colitis, Crohn’s disease, gastrointestinal cancers, or other conditions that cause blood loss or malabsorption.

Which supplemental iron is best?

Iron supplements are not the same. Ferrous iron (ferrous sulfate) is much better absorbed than ferric iron (ferric citrate). The most common form of iron supplement is ferrous sulfate, but it is known to produce intestinal side effects (such as constipation, nausea, and bloating) in many users. Other forms of iron supplements (such as ferrous fumarate, ferrous gluconate, heme iron concentrate, and iron glycine amino acid chelate) are well-absorbed and less likely to cause intestinal side effects.

How much should be taken?

If a doctor diagnoses iron defiency, iron supplementation is necessary. To treat iron deficiency, the usual recommended amount for an adult is 100 mg per day (this amount is reduced after the deficiency is corrected).

Some premenopausal women become marginally iron deficient unless they supplement with iron. However, the 18 mg of iron present in many multivitamin-mineral supplements is often adequate to prevent deficiency. Consult a doctor to determine the amount of iron you need.

Are there any side effects or interactions?

Iron (ferrous sulfate) is the leading cause of accidental poisonings in children. Many of these children obtained the iron from a child-resistant container opened by themselves or another child, or left open or improperly closed by an adult. Deaths in children have occurred from ingesting as little as 200 mg to as much as 5.85 grams of iron. Keep iron-containing supplements out of children’s reach.

Some researchers have linked excess iron levels to diabetes, cancer, increased risk of infection, exacerbation of rheumatoid arthritis, among others. The greatest concern has to do with the possibility that excess storage of iron in the body increases the risk of heart disease. One study has suggested that such a link may exist, but possibly only in people who smoke or those with elevated cholesterol levels. Nevertheless, be wary as too much iron causes free radical damage. Those who are not iron deficient should generally not take iron supplements.

What foods, beverages, supplements decrease the absorption of iron?

These include tea (drinking green tea with meals has been shown to reduce the absorption of iron from food by about 70 percent); coffee; red wine, particularly the polyphenol component; phytate (phytic acid), found in unleavened wheat products such as pita and some rye crackers; wheat germ, oats, nuts, cacao powder, vanilla extract, beans, etc.; whole wheat bran; calcium from food and supplements; soy protein, eggs.

What foods/supplements increase iron absorption?

Meat, poultry, and fish. Certain soy-containing foods (like tofu, miso, tempeh) as well as soy sauce have been shown to improve iron absorption. Vitamin A improves the absorption and utilization of iron.