Blood donation good for your cardiac health
Published 4:00 am Thursday, February 22, 2007
- Blood donation good for your cardiac health
Donating blood can save the lives of others. But new research suggests there might be a benefit to the donor as well.
A study from researchers at Dartmouth Medical School found that lowering the body’s excess supply of iron, such as through blood donation, can improve cardiac health.
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Excess iron in the blood is believed to damage the arteries, particularly in the early stages of arteriosclerosis, a narrowing and hardening of the arteries that is a major risk factor for heart attack and stroke. The researchers believed that premenopausal women have lower cardiovascular risk than men because they regularly lose blood and excess iron through menstruation.
Two large studies in the 1990s supported the notion. They found that men who donated blood had fewer cardiac problems than those who didn’t donate. But other studies have shown mixed results and the topic remains controversial.
The Dartmouth researchers, led by Dr. Leo Zacharski, studied nearly 1,300 men and women with peripheral artery disease, a hardening or narrowing of arteries outside the heart or brain, randomly assigning them to either a blood donation group or a control group. At the end of the six-year study, there was little difference in overall death rates between those who donated blood and those who did not. And there was no difference in the number of nonfatal heart attacks and strokes between the two groups.
But when researchers looked at results for those test subjects under the age of 61, they found 54 percent fewer deaths among the blood donation group, and fewer heart attacks and strokes.
”The secret is the age effect,” Zacharski says. ”While our study did not show that reducing iron led to across-the-board decreases in overall mortality, or combined death plus nonfatal myocardial infarction and stroke, it did support the theory that vascular health might be preserved into later life by maintaining low levels of iron over time.”
The researchers suspect that the toxic effects of excess iron may become permanent at an older age and that the benefits of reducing iron levels in the blood can only be realized if it is done early and regularly.
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”Our data suggest that iron may contribute to the development of arteriosclerosis relatively early in its course, and that long-term iron maintenance – in combination with other lifestyle modifications – may help slow or reverse the process,” Zacharski says. ”But ours is just a beginning and more controlled studies are needed.”
The researchers emphasized that they would not recommend patients donate blood simply to lower their iron levels. Other strategies, such as dietary restriction and medications, can be used to achieve the same effect.
Individuals who have iron deficiencies should also avoid donating blood. One in five women, and half of all pregnant women, are iron deficient. Physicians normally test iron levels as part of routine checkups, and blood donation centers test for iron content before allowing people to donate.