Iron: Are We Getting Too Much?
Schardt, David, Nutrition Action Healthletter
"I feel like the luckiest guy alive," says Nutrition Action subscriber Davis "Doc" Ball, 57, of San Antonio, Texas. "I had no idea how sick I was until last June, when my doctor happened to notice something unusual on a routine blood test."
The doctor's discovery: Ball's blood was loaded with more than enough iron to kill him.
As it turns out, "Doc" is one of the estimated one million Americans who suffer from iron overload, or hemochromatosis.
For most adult males and postmenopausal women, getting enough iron isn't a problem. It's everywhere - in meat, enriched-flour breads and pastas, fortified breakfast cereals, and most multivitamins.
But getting too much can mean trouble for people with iron overload, like "Doc" Ball. And now some researchers are saying that iron may be linked to cancer and heart disease So far, though, the evidence is skimpy.
For most people, hemochromatosis [HEE-mow-CROW-muh-TOW-sis] comes down to a flip of the genetic coin. If you happened to inherit two hemochromatosis genes, one from your mother and one from your father, you've got it.
"About one out of every 250 Americans does, which makes it the most common genetic illness among whites," says iron expert Eugene Weinberg of Indiana University.
Men who have the disease are more likely to feel its effects than women, possibly because they don't spend 30-some-odd years regularly losing iron during menstruation.
"People with hemochromatosis absorb about twice as much iron from their food and supplements as other people do," says Weinberg. The extra iron is stored in the liver, pancreas, heart, and brain. For four or more decades, our bodies can bear the overload without discomfort or irreparable damage.
"But eventually, usually in men after age 50, the iron starts to damage the liver and other organs," says expert Bruce Bacon of the St. Louis University School of Medicine.
"If patients are early in the disease," he explains, "they may feel fine. Later on, they may complain of fatigue, impotence, or symptoms of diabetes like persistent thirst or the need to urinate frequently."
If it's caught soon enough, the damage can be prevented. A simple blood test can tell your doctor if you're at risk (see "What to Do").
"Treatment consists of removing excess iron from the body," says Weinberg. That means regular blood "donations" (they're donated to the trash bin, since most blood banks won't accept blood from people with hemochromatosis).
But if you're not one of the million Americans with the disease, do you still have to worry about iron?
Rats exposed to a chemical that causes breast cancer develop one-third more tumors when they are also given ten times their normal iron ration.(1)
When it comes to humans, though, "the body of evidence is small," acknowledges researcher Richard Stevens of the Pacific Northwest Laboratory in Richland, Washington.
In one study, Richard Nelson and his colleagues at the University of Illinois College of Medicine at Chicago looked at the blood ferritin levels of 304 men and women whose colons had been examined as part of another study. (Ferritin is the form iron takes when it's stored in the body.)
Those with the most ferritin were more than four times as likely to have adenomas (benign polyps) as those with the least ferritin.(2) Adenomas often turn into colon cancer.
That jibed with the results of a similar study by Richard Stevens. Among 198 Taiwanese government workers those who died of liver cancer had significantly higher ferritin levels before they were diagnosed than those who remained cancer-free.(3)
But that's not the same as proving that too much iron causes cancer. "There's just not enough research yet to reach a conclusion about the role of iron in human cancer," says Alberto Ascherio of the Harvard School of Public Health.
Researchers don't know exactly why arteries sometimes start to clog. …