Now scientists have found that young blood actually ‘recharges’ the brain, forms new blood vessels and improves memory and learning.
In parallel research, scientists at Harvard University also discovered that a ‘youth protein’ which circulates in the blood is responsible for keeping the brain and muscles young and strong.
The protein, known as ‘GDF11’, is present in the bloodstream in large quantities when we are young but peters out as we age.
Although both the discoveries were made in mice, researchers are hoping to begin human trials in the next two to three years, in studies which could bring rapid improvements for human longevity and health.
“This should give us all hope for a healthier future,” said Prof Doug Melton, of Harvard's Department of Stem Cell and Regenerative Biology.
“We all wonder why we were stronger and mentally more agile when young, and these two unusually exciting papers actually point to a possible answer.
“There seems to be little question that, GDF11 has an amazing capacity to restore aging muscle and brain function.”
Last year the team discovered that the protein could repair damaged hearts. But the new study showed that that raising the levels of the GDF11 protein in older mice improved the function of every organ in the body.
Harvard stem cell biologist Prof Lee Rubin added: “We do think that, at least in principal, there will be a way to reverse some of the decline of aging with a single protein.