Is Iron a Killer?
11/30/1992 AT 01:00 AM EST
11/30/1992 AT 01:00 AM EST
Eleven years ago no one in the medical establishment paid much attention when Dr. Jerome L. Sullivan, a young resident in pathology at the University of South Florida, published his theory that excess iron in the blood might contribute to heart attacks. Until then, iron was considered beneficial, and too little of it was known to cause anemia. Now, Sullivan, 48, director of clinical laboratories of the Veterans Affairs Medical Center at Charleston, S.C., has been vindicated. This fall researchers at the University of Kuopio in Finland announced the results of a large-scale study indicating that, next to smoking, excess stored iron is the most significant identifiable risk factor for heart attacks.
"We don't know exactly what iron does, but we do know that too much can promote injury to the heart muscle," says Dr. Sullivan, who lives in Charleston with his wife, Laura, also a pathologist. Seated at a paper-strewn desk in his cramped office, with a Mozart piano sonata playing in the background, he discussed the new findings with correspondent Don Sider.
What was discovered in the Finnish research?
The study, which tracked nearly 2,000 men for up to five years, revealed that stored iron was stronger than high blood pressure and cholesterol as a risk factor for heart attack.
What made yon suspect 11 years ago that excess iron might be a culprit?
I had gotten interested in why young women don't have heart attacks. The landmark Framingham [Mass.] Heart Study, which, beginning in 1950, has followed about 5,000 men and women, recorded an increasing pattern of cardiac events in men as early as their 30s. Women, however, didn't start showing a similar pattern of heart attacks until after menopause—roughly 10 years after the men. This has usually been attributed to a decrease in the female hormone estrogen. But young women who underwent partial hysterectomies showed the same increase in heart attacks, even though their ovaries continued to produce estrogen. This suggested that blood loss, rather than estrogen loss, was in some way protecting women from heart attacks.
Why would blood loss protect women?
Stored iron, as measured by a blood protein called ferritin, is low in menstruating women because of the regular loss of iron-rich red blood cells. Men have low ferritin levels in their teens, but when they stop growing, their bodies begin to accumulate iron and ferritin. Women's fern tin levels remain flat until they reach 40 to 45. By age 45, men have accumulated four times the ferritin in their blood as women—and suffer four times the rate of heart attacks. The age curves for heart disease among men and women reflect exactly the curves of ferritin levels.
Is there oilier evidence that blood loss helps prevent heart attack?
Heart attacks are virtually unknown in areas of the world where iron deficiency is common. Parasites in certain regions cause micro-bleeding in the gut that seems to protect men the same way menstruation protects women. I believe aspirin may be similarly protective since it also causes minor internal bleeding. Conversely, women who take oral contraceptives lose less menstrual blood, have higher ferritin levels and run a greater risk of heart attacks.
How-much iron is too much?
You need iron to make red blood cells. If you have too few of those, you are, by definition, anemic. But you don't need any ferritin—stored iron—to prevent anemia. So my personal opinion is that a ferritin level of 200—considered normal in adults and easily measured in a lab test—is, in fact, too high.
Can one lower iron through diet?
No. You can add to your store of iron by eating foods like red meat and spinach, but you cannot easily rid the body of significant amounts of ferritin through diet. I feel we should be cautious about overuse of iron supplements and overconsumption of iron-rich foods.
How, then, can one rid the body of excess iron?
Blood donation is the most effective way of reducing ferritin levels. More studies need to be done, but my theory also predicts that donating blood three times a year will be protective against heart attack. It may be one instance in which an altruistic act pays instant dividends.