One answer to why we have different lifespans is genetic. Cynthia Kenyon – at the Hillblom Centre for the Biology of Ageing at the University of California, San Francisco – working with flatworms found that if she knocks out the gene that produces growth hormones, the flatworms live longer and healthier.
Similarly, Richard Miller from the Geriatrics Centre of the Medical School, University of Michigan, working with naturally occurring long-lived and sterile mice, showed that having a diminished growth hormone production (or reception) seems to increase longevity.
The body seems to knows that it needs to live longer to pass on its genes. If the body has stunted growth, then it knows that it needs to survive longer to be able to pass on its genes. But we do not know exactly how this works. Michael Rose’s experiments with flies at the Department of Ecology and Evolutionary Biology at the University of California, Irvine, provides another twist to this story.
By collecting eggs laid by older flies, Rose started seeing offspring that lived longer. There seems to be an expiration date stamped on our genes. This also works for humans. The older our parents, the longer we seem to survive. But there are many factors involved other than age of parents. Educational level and economic status are two factors that determine late progeny. But there are other more interesting, if not altogether more accurate, explanations.
If we are stunted in growth or our parents delayed producing us, then our body seems to know that it needs to live longer to pass on our genes. The best way to explain this is through the disposable soma theory. This theory, first developed in 1977 by a biologist named Thomas Kirkwood, who now heads The Institute for Ageing and Health in its School of Clinical Medical Sciences at Newcastle University, states that the body protects itself just enough so that we are able to pass on our genes. The body is disposable; it is a carrier for the genetic material. We have to compromise between maintaining the body and living longer.
What if we cheated our body? Are there experiments that cheat the body into thinking that they are developing really slowly and therefore needing more time to be able to pass on its genes?
Castration might be the answer. The first time that eunuchs – boys who had their testicles and sometimes their penis removed surgically – featured in the longevity debate was with the observation by Serge Voronoff in the early 1900s. And it was not a positive observation.
The body seems to knows that it needs to live longer to pass on its genes
Voronoff, a French surgeon of Russian descent, worked at a hospital in Cairo from 1896 to 1910, where he had the opportunity to observe eunuchs. He noted their obesity, lack of body hair and broad pelvises, as well as their flaccid muscles, lethargic movements, memory problems and lowered intelligence. He concluded that the absence of testicles was responsible for ageing and that their presence should prompt bone, muscle, nerve and psychological development. He saw ageing as the result of the lack of substance from the testicles and ovaries. But then a new study in 2012 by Kyung-Jin Min from Inha University and his Korean colleagues reversed this finding. In their study, the authors reported that during the Chosun dynasty between the 14th and early 20th centuries, Korean eunuchs lived 14 to 19 years longer than other (intact) men.
Researchers were able to identify 81 eunuchs, who were castrated as boys and determined that they lived to an average age of 70, significantly longer than other men of similar social status. Three of the eunuchs lived to 100. This is a centenarian rate that’s far higher than would be expected today.
Historically and, as recent as the 19th century, eunuchs were common across the world. Castrati boys, castrated before puberty, were among the most prized singers especially in Catholic churches in Italy (the Sistine Chapel retained the last of the castrati singers) and opera houses in Vienna. Many of these boys were castrated at a monastery in Upper Egypt by Coptic priests. The practice was pervasive and endemic.
Elsewhere, eunuchs were hired staff in harems and imperial palaces in Europe, Russia, Africa, China, Korea, Japan and the rest of Asia and the Middle East. In the 18th century, there was a Christian sect called the Skoptzy, also called the White Doves, whose male members – to attain their ideal of sanctity – subjected themselves to castration. They believed that the Messiah would not come until the Skoptsy numbered 144,000 (Rev. 14:1,4). But whether castration makes you live longer was not addressed until 1968.
James Hamilton and Gordon Mestler, from the Department of Anatomy, State University of New York College of Medicine, studied the mortality of patients in a mental institution. At the turn of the century, it was common practice to castrate/sterilise mental health patients as part of the eugenics movement – keeping the human stock clean of ‘unwanteds’. They reported that castration reduced the age of death by 0.28 years for every year of castration from age 39 and younger. But it is not just about biology.
The world was very different 600 years or even 100 years ago. In most cases it was a very violent world where men suffered early mortality through wars, famine and daily trauma.
Eunuchs, because of their demeanor might have escaped all of that onslaught of violence. They might also have had more nurturing qualities that extended to looking after themselves better. We might never know, but for now it is best to keep everything intact.
Mario Garrett was born in Malta and is currently a professor of gerontology at San Diego State University in California, US.