Iron

Claims, Benefits: Prevents anemia, but increases the risk of heart disease.

Bottom Line: You are a young woman, a dieter, or endurance athlete, you may not be getting enough iron, even if you have a good diet. But they should consult a doctor before taking an iron supplement. The theory that a high iron intake causes heart disease remains unproven. But one million Americans do need to worry about iron overload: they have a hereditary disorder known as hemochromatosis, which causes them to absorb and store too much iron.

Full article, Wellness Letter, February 2004:

Why Iron Is Hot

Thanks to years of Geritol commercials about “tired blood,” most people know that iron is a nutrient they should pay attention to. It was the iron in spinach that put the pop in Popeye’s muscles(the iron in spinach actually isn’t well absorbed—sorry, Popeye). And most of us have heard that millions of Americans, especially women of childbearing age, have an iron deficiency and may even be anemic.

However, since 1992, when a widely publicized Finnish study suggested that a high level of iron in--creases the risk of a heart attack, more and more researchers have been warning about the dangers of getting too much iron. This has led many people to avoid iron—or at least to stop trying to get enough of it. Should you look at iron as a friend or foe?

Casting iron as a villain

The theory linking high levels of stored iron (usually measured as ferritin) in the body with coronary artery disease (CAD) was first proposed in 1981. According to it, some factors that affect the risk for a heart attack can be explained by their effect on the body’s iron level. Notably, premenopausal women may be at lower cardiac risk because their menstrual blood loss keeps their iron stores low; thus after menopause, women’s iron stores rise, as does their CAD risk.

The 1992 study found that among men from eastern Finland (where the average ferritin level and death rate from heart attacks are among the highest in the world), those with higher levels of ferritin were twice as likely to have a heart attack as men with lower levels. Since then many studies have looked at the iron question. Most have not found a link between iron levels in the body and CAD.

The iron you eat

Nearly all the studies have focused on iron stored in the body, not the amount of iron people eat. The correlation between the two is small: the body doesn’t simply store away extra iron from foods. The absorption process is affected not only by the amount of iron you eat, but also by its sources (for instance, the “heme” iron in meat is best absorbed), the composition of your meals, genetic factors, and your body’s needs (if your iron stores are low or you have greater needs because of rapid growth or pregnancy, for instance, you absorb more iron through the intestinal tract). Thus, an iron-rich diet by itself won’t necessarily lead to high iron levels. The exceptions: some people are genetically predisposed to over-absorb iron and must limit their consumption of iron.

The genetic issue: hemochromatosis

There is no dispute that some people do need to worry about iron overload: about one million Americans (mostly of northern European descent) have a hereditary disorder known as hemochromatosis, which causes them to absorb and store too much iron. When untreated, this can lead to weakness, headaches, darkening of skin color, sexual dysfunction, and joint pain, and eventually diabetes, arthritis, liver disease, or heart failure (but not CAD and heart attacks). People with hemochromatosis must have blood removed frequently to lower their iron levels, and they must avoid iron supplements.

Many more people, about 10 to 15% of Americans, carry only one gene for hemochromatosis (it takes two genes to develop the full-blown disorder) and may accumulate slightly higher-than-average stores of iron, but it’s not known if this affects their health. Some studies have found that those who carry one gene for hemochromatosis have an increased coronary risk, but others have not. One recent study in the Journal of the National Cancer Institute found that they have an increased risk of colon cancer—a finding that will need to be confirmed by future studies.

If you have a family history of hemochromatosis or develop symptoms that may be related to it, a simple, inexpensive blood test can help diagnose it. Many doctors advise routine screening for hemochromatosis in middle age, especially for Caucasians.

Iron deficiency is still an issue

All cells in the body contain iron, which plays a vital role in many biochemical reactions. Most iron is incorporat-ed in hemoglobin, which carries oxygen in the blood, and in myoglobin in muscle; it is also stored in the liver, spleen, and bone marrow. Low iron intake over a long period can lead to a depletion of these stores, especially if the body is losing blood, as in menstruation. This depletion reduces production of hemoglobin and red blood cells.

The initial stage of iron deficiency usually has no symp-toms. The second stage occurs when the iron supply in the bone marrow falls short of that needed to produce healthy red blood cells. If the iron balance worsens, full-blown iron-deficiency anemia can gradually develop. Since iron is an essential component of hemoglobin, a shortage of iron can impair the transport of oxygen from the lungs to the body’s cells. It can take months or even years for symptoms of iron defi-ciency—such as weakness, shortness of breath, paleness, poor appetite, and increased susceptibility to infection—to become evident.

It’s estimated that at least 10% of women under 50 have some degree of deficiency. And in some develop-ing countries, where people eat less meat and iron-enriched foods, half the population may be iron-deficient.

Even if you consume a balanced diet, you may not be getting adequate iron if you are in one of these groups:

• Premenopausal women, especially those who bleed heavily during menstruation, since blood losses increase iron needs.

• Pregnant women. Iron needs increase because of the de--mands of increased blood production by the mother and the needs of the fetus and the placenta.

• Dieters, especially premenopausal women. The less you eat, the less likely you are to get enough iron.

• Long-distance runners and other high-impact endurance athletes, especially women and vegetarians, tend to have a higher incidence of iron deficiency, which can impair performance.

• Infants, children, and adolescents. Youngsters need a high iron intake because of their rapid growth; deficiencies may impair their learning capacity.

What to do

Eat foods that supply your daily requirement of iron (18 milligrams a day for premenopausal women, 8 milligrams for men and older women). There is no benefit in exceeding these levels. Meats, poultry, and fish contain iron in the heme form, which is best absorbed by the body. Iron is also found in nuts, whole grains, beans, and some vegetables, but this is less well absorbed than the iron from meats. Enriched pasta and breads and fortified breakfast cereals are also sources. Cooking acidic foods (such as tomatoes) in iron pots adds iron to them. Consuming foods rich in vitamin C, as well as small amounts of meat, boosts the absorption of iron from plant sources. Vegetarians can get enough iron from their diet if they consume C-rich foods. Most multi-vitamin/mineral pills contain 18 milligrams.

If you fall into one of the groups above, you may need an iron supplement. But before taking one, consult your doctor. Don’t take extra iron just because you are tired and think you may be anemic. Weakness and fatigue can be symptoms of many other conditions.

And by the way: Men, as well as postmenopausal women, do not need iron in their multivitamins, since they need only 8 milligrams of iron a day. The amount in a multi probably won’t hurt them, unless they have hemochromatosis. Still, there’s no reason for them to load up on iron.

UC Berkeley Wellness Letter, February 2004