Then donate a pint. It may protect you against heart disease.
May 1, 2000 (Atlanta) -- At a time when blood banks report dangerously low supplies, the best argument for rolling up your sleeve is still to do someone else some good. But if University of Florida researcher Jerome Sullivan, MD, is right -- and there's new evidence to suggest he is -- giving blood could also save your life.
Here's why. Each time you give blood, you remove some of the iron it contains. High blood iron levels, Sullivan believes, can increase the risk of heart disease. Iron has been shown to speed the oxidation of cholesterol, a process thought to increase the damage to arteries that ultimately leads to cardiovascular disease.
Do you insist on rising at five to run each morning, even when your back is
aching, black ice coats the streets, and your wife beseeches you to stay in
bed? Do you only feel good when you’re training for triathlons? Is eating
merely a way to replenish for the next race? Then you, my Spandex-clad friend,
may have an exercise addiction.
Sullivan has long suspected that blood iron levels help explain why a man's risk of heart disease begins earlier than a woman's. Women lose blood -- and lower their iron levels -- each time they menstruate. Men, on the other hand, begin storing iron in body tissues starting in their twenties, which is just about the time their heart attack danger begins to climb. According to Victor Herbert, MD, a hematologist at the Mt. Sinai School of Medicine in New York City, there are normally about 1,000 milligrams of iron "stored" in the average adult man's body but only about 300 milligrams in a premenopausal woman's. Once women stop menstruating, however, their iron levels -- and their heart disease risk -- begin to climb, eventually matching that of men.
Not everyone's convinced by Sullivan's notion. "I do not believe there is proof of an association between iron level and the risk of heart disease in men with normal iron metabolism," says Peter Tomasulo, MD, a director at the International Federation of Red Cross Societies. "The data is preliminary at best." Most scientists, in fact, still think estrogen is probably the most important reason why women are protected from heart disease until they reach menopause.
But several recent findings lend support to the possibility that iron levels play a role. In research reported last year in the journal Circulation, Swedish scientists found that men with a genetic abnormality that causes slightly elevated blood iron levels had a 2.3-fold increase in heart attack risk. A second study published in the same journal found that women with the abnormal gene were also at greater risk of cardiovascular disease. Together, Sullivan believes, those studies offer new support for his iron hypothesis.
Proof won't come until researchers conduct large and well-controlled studies that compare the heart disease risk of men who regularly give blood with that of men who don't. Already several small studies have been done, however, offering tantalizing evidence that donating blood might be a very good idea.
Take, for example, a study of 2,682 men in Finland reported in the September 1998 issue of the American Journal of Epidemiology. Men who donated blood at least once a year had an 88% lower risk of heart attacks than nondonors. Another study published in the August 1997 issue of Heart found that men who donated blood were less likely than nondonors to show signs of cardiovascular disease.