The Danger of Too Much Iron

A growing number of doctors are now convinced that for many people, too much iron in the blood is a bigger health problem than too little.

“For years we were getting, ‘Rah, rah, the more iron the better.’ Now that has changed around completely,” said Richard Stevens, a cancer epidemiologist at University of Connecticut Health Center who has studied the potential health risks of elevated levels of iron.

Iron deficiency is a significant problem for many people, particularly women of childbearing age. In the last decade, however, evidence has mounted that high levels of iron can have severe, even fatal consequences, for people who can’t properly absorb the vital, but potentially toxic, mineral.

Particularly at risk are men and post-menopausal women of Northern European ancestry--the groups most susceptible to genetic mutations that can lead to hemochromatosis, in which iron is excessively absorbed in the liver, pancreas and other organs.

Hemochromatosis can lead to cirrhosis, diabetes, arthritis and impotence and has been implicated in some forms of heart disease and cancer. The damage is irreversible unless it’s discovered early. If it is, a change in diet, such as reducing consumption of red meat and alcohol and an ancient treatment, blood-letting, can help return iron in the blood to normal levels.

The problem is that most of the early symptoms of hemochromatosis, such as fatigue, joint pain, sexual dysfunction in men and frequent headaches in women, are also symptoms in more common disorders. A more specific symptom--bronzing of the skin-- doesn’t always occur, experts say.

Also complicating the issue is that while the health threats of hemochromatosis are clear, much uncertainty remains about how many people are at risk of contracting the disease and the level of risk posed by moderately elevated levels of iron.

Most hemochromatosis patients have genetic mutations that predispose them to the disease. By one estimate, as many as one in 250 people of Northern European ancestry possess two copies of the mutation, making it one of the more common genetic diseases. But many people with the mutations do not develop hemochromatosis.

The risk of developing excess iron levels seems to increase with age.

Last year, Dr. Richard Wood, a Tufts University nutrition expert, and his colleagues analyzed blood iron levels in more than 1,000 men and women, ages 67 to 96, in the landmark, long-term Framingham Heart Study. While 2.7% had abnormally low levels of iron, more than four times that many-- 12.9%--had too much of the mineral, according to the research, published in the American Journal of Clinical Nutrition.

Stevens’ studies have suggested that even moderately high levels of iron can increase the risk of cancer. Animal studies have shown conclusively that iron is indeed a carcinogen, he said.

However, there is some ambiguity in studies on the health risks of excess iron, noted Dr. Herbert Bonkovsky, director of clinical research at the Liver-Biliary-Pancreatic Center at the University of Connecticut Health Center.

For instance, one recent study showed people with a genetic predisposition to hemochromatosis did not appear to suffer any more health problems than those without the mutation, he said.

Bonkovsky suggests that men over 40 and women over 50 get tested for iron levels, which is generally not included as part of most physicals.