News Release

Tuesday, February 10, 2015

Study shows iron supplementation after blood donation shortens hemoglobin recovery time

About 25-35 percent of regular blood donors develop iron deficiency.

A National Institutes of Health-funded study comparing low dose iron supplementation to no supplementation in blood donors found that supplementation significantly reduced the time to recovery of post-donation lost iron and hemoglobin — an iron-rich protein that carries oxygen in red blood cells throughout the body.

The results of the Hemoglobin and Iron Recovery Study (HEIRS), supported by NIH’s National Heart, Lung, and Blood Institute (NHLBI), will appear Feb. 10 in the Journal of the American Medical Association.

Blood donors are allowed to give one pint of blood every eight weeks. A major concern is that about 25-35 percent of regular donors develop iron deficiency. Since iron is needed for red blood cell production, low iron can cause fatigue and anemia — a condition in which the blood has a lower than normal number of red blood cells — and can lead to temporary ineligibility for future donations. It can take months to recover the lost iron. New research indicates a possible solution.

“Maintaining healthy iron levels will allow donors to safely continue donating thereby ensuring a robust blood supply for patients in need.”

Simone Glynn, M.D., M.S.c, M.P.H
Chief of the Blood Epidemiology and Clinical Therapeutics Branch, NHLBI

“This research brings us another step closer to understanding how to maintain healthy iron levels in blood donors. Maintaining healthy iron levels will allow donors to safely continue donating thereby ensuring a robust blood supply for patients in need,” said Simone Glynn, M.D., M.S.c, M.P.H., chief of the Blood Epidemiology and Clinical Therapeutics Branch at NHLBI.

The randomized trial ran from April 2012 to December 2012 at four blood centers in the United States and included 215 blood donors aged 18 and older. The study was conducted by the NHLBI-supported Recipient Epidemiology and Donor Evaluation Study-III (REDS-III), a large, multicenter research program that seeks to optimize health outcomes in donors and transfusion recipients and to help ensure the safety and availability of transfused blood products in the United States and internationally.

“Donating blood is safe and essential for health care. This study highlights the importance of maintaining iron levels after blood donation, and shows that supplemental iron effectively restores hemoglobin, even in donors with higher iron levels,” explained the study’s principal investigator, Joseph Kiss, M.D., medical director at the Institute for Transfusion Medicine and associate professor of medicine, University of Pittsburgh.

The study measured the effect of low dose daily iron supplementation on the time to recovery of lost hemoglobin and iron after donating a unit of blood. Participants included 136 females (63 percent) and 79 males (37 percent); 52 donors (24 percent) were 60 years or older. Although all were blood donors, none had donated blood in the last four months.

Researchers separated the blood donors into two groups based on their iron levels: a lower iron and a higher iron group.  Half of each group was randomized to take one tablet of ferrous gluconate (38 mg of low dose iron) daily for 24 weeks following their blood donation. Hemoglobin and iron levels were measured seven times during the study. Compared to donors who did not take iron, the donors taking iron supplements returned to pre-donation hemoglobin levels faster in both the lower iron (five weeks versus 23 weeks) and higher iron groups (four weeks versus 11 weeks). Similarly, donors taking iron supplements recovered lost iron more rapidly than those not receiving supplements (11 weeks versus more than 24 weeks). Without iron supplementation, two thirds of the donors did not recover the iron lost from donating blood after 24 weeks.

“The NHLBI is supporting additional research to address questions such as who benefits most from iron supplementation, how much iron should be taken, and for how long. This research can help encourage blood centers to evaluate best strategies on how to help donors maintain iron levels and prompt all donors to discuss iron supplementation with their physician,” concluded Dr. Glynn.

The trial was supported by contracts from the NHLBI (HHSN268201100001I, HHSN268201100002I, HHSN268201100003I, HHSN268201100004I, HHSN268201100005I, and HHSN268201100006I).

For additional information or to arrange an interview with Dr. Glynn please contact the NHLBI office of Communications at 301-496-4236 or To arrange an interview with Dr. Kiss please contact Tamara Kilgore, at the Institute for Transfusion Medicine at 412-209-7029 or

Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available online at

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