Healthy adults usually have about 5 grams of iron in their bodies, mostly in red blood cells but also in bone marrow. When you donate a unit of blood, you lose about a quarter of a gram of iron, which gets replenished from the food you eat in the weeks after donation, Dr. DeChristopher says. This regulation of iron levels is a good thing, because having too much iron could be bad news for your blood vessels.
“The statistics appear to show that decreasing the amount of iron in otherwise healthy people over the long run is beneficial to their blood vessels, and diseases related to abnormalities in blood vessels, such as heart attack and stroke,” he says.
Still, data from The Centers for Disease Control and Prevention says that nearly 10% of women in the U.S. suffer from anemia, a condition where your body lacks red blood cells or hemoglobin (most commonly due to an iron deficiency). In that case, it’s best not to give blood until the anemia is resolved, he says.
Women who haven’t hit menopause yet may find it hard to donate blood, too. “Pre-menopausal females can be somewhat iron depleted with blood counts just under the lower limit,” Dr. DeChristopher says. If you have low iron and you still want to be a donor, taking an oral iron supplement may help you re-qualify, he says.
You could live longer
Doing good for others is one way to live a longer life. A study in Health Psychologyfound that people who volunteered for altruistic reasons had a significantly reduced risk of mortality four years later than those who volunteered for themselves alone. While the health benefits of donating blood are nice, don’t forget who you’re really helping: A single donation can save the lives of up to three people, according to the Red Cross. “The need for blood is always there,” Dr. DeChristopher says. “It’s important to recognize how important willing donors are.”