Donating Your Blood Could Have a Surprising Health Benefit

Your regular donation of blood could be doing some good for your own health. Researchers have found early evidence that blood donation can trigger helpful changes in the cells that replenish our blood supply.

Scientists at the Francis Crick Institute and others conducted the study, published Tuesday in the journal Blood. Studying blood samples from frequent donors, the scientists identified genetic mutations in the stem cells that turn into blood cells—mutations that might improve the body’s response to blood loss, but without raising the risk of blood-related cancers like leukemia. The findings might help scientists better understand these cancers, though more research is needed to know whether donation actually protects people from developing such conditions.

Plenty of research has shown the immense public health value of blood donation, as well as the overall safety of the procedure for prospective donors. But according to the study researchers, there has been less focus paid on how blood donation might affect the health of frequent donors, particularly when it comes to their hematopoietic stem cells, the cells that replace every type of mature blood cell. So they decided to analyze HSCs collected from 200 older frequent donors—defined as donating more than 100 times in a lifetime—and compared them to HSCs from similarly aged sporadic donors who donated less than 10 times during their lifetime (a control group).

When our HSCs mature, they will sometimes develop mutations that result in a separate population of blood cells slightly genetically different from other blood cells. This phenomenon is called clonal hematopoiesis (CH) and the populations are called clones. CH becomes more common as we age, but it’s usually harmless. Rarely, however, the clones carry mutations that predispose them to becoming cancerous.

The researchers found that frequent blood donors were about as likely as the sporadic donors to develop CH. But when they looked closer, they noticed that the clones from frequent donors carried mutations distinct from those in the control group, particularly in a gene called DNMT3A (a common area of genetic change in CH).

Further experiments with CRISPR-edited human HSCs and with mice suggested that the DNMT3A-related changes seen in frequent donors might be positive. The changes appeared to boost the cells’ ability to regenerate new red blood cells under stressful conditions mimicking blood loss, for instance. They didn’t grow in conditions mimicking inflammation (a risk factor for cancerous growth), whereas the opposite was true for HSCs that had changes known to increase the risk of leukemia.

All in all, the researchers speculate that blood donation might give our blood stem cells a healthy workout, one that could even make them more resistant to cancer.

“Our work is a fascinating example of how our genes interact with the environment and as we age,” said senior study author Dominique Bonnet, group leader of the HSC Laboratory at Crick, in a statement from the institute. “Activities that put low levels of stress on blood cell production allow our blood stem cells to renew and we think this favors mutations that further promote stem cell growth rather than disease.”

Bonnet and her team note that it’s not yet clear whether these discovered mutations are truly cancer-preventing. More research and studies with larger sample sizes are needed to get to the bottom of this question, which the team is already planning to conduct. “We’re now aiming to work out how these different types of mutations play a role in developing leukemia or not, and whether they can be targeted therapeutically,” said co-lead author Hector Huerga Encabo, a postdoctoral fellow in the HSC Laboratory at Crick, in a statement.

But at the very least, the researchers haven’t found anything that should concern any potential frequent blood donor. And if their work does eventually confirm a real cancer-related benefit from the practice, it’d be the latest in a long list of potential reasons why you should donate blood if you can. In addition to the life-saving gift you’re giving others, blood donation has been associated with a lower risk of heart attack, for instance.