There comes a time when the way we live becomes more than just the way we live, but also the way we might die. However, in apparent defiance of this simple inevitability, new research into human longevity — how long we have to live — suggests our years alive on planet Earth may be vitally linked to blood iron levels, according to a recent paper published in the journal Nature Communications.
Human longevity linked to blood iron levels
While a skeptical frame of mind is best when it comes to longevity studies, this recent research involved an impressive breadth of genetic information gathered from more than 1 million people throughout three public databases. It also considered three key features of aging: years lived without disease (also called healthspan), lifespan, and surviving until extremely old age (or rather, longevity).
The analysis linked 10 key regions of the genome to these three measures of long life — in addition to gene sets linked to the body's metabolization of iron. In other words, too much iron in the blood appears to raise the chances of early death, reports Science Alert.
"We are very excited by these findings as they strongly suggest that high levels of iron in the blood reduces our healthy years of life, and keeping these levels in check could prevent age-related damage," said Paul Timmers, a data analyst from the University of Edinburgh in the U.K.
"We speculate that our findings on iron metabolism might also start to explain why very high levels of iron-rich red meat in the diet has been linked to age-related conditions such as heart disease," he added.
Skeptical precautions, gene effects, lifespan, healthspan
While correlation doesn't mean causation, not necessarily — the researchers reduced bias and sources of causal inference in the data using a statistical technique called Mendelian randomization.
The researchers took note of how genetics are considered to have a roughly 10% influence on lifespan and healthspan — which might make it hard to decide which genes are linked to longevity, as opposed to other factors (like drinking and smoking habits). With these in mind, one of the advantages of this new study lies in its uncommon scope and size.
Five genetic markers show links to aging process
Five genetic markers not typically associated with longevity were found to bear significance at the genome-wide level in this study. Some of which — like FOX03 and APOE — were singled out in the past as possibly important to human health and the aging process.
"It is clear from the association of age-related diseases and the well-known aging loci APOE and FOX03 that we are capturing the human aging process to some extent," wrote the researchers in the new paper.
Future longevity studies might add extra years
This investigation into the links between longevity and iron metabolism is still at an early stage, but someday we might see new drugs designed to reduce the iron levels in blood to possibly add extra years to our lives.
Blood iron is mostly influenced by diet choices, and is already associated with various age-related diseases like liver disease and Parkinson's. Additionally, blood iron affects the body's ability to combat infection as we age.
10 genome regions linked to healthspan, lifespan
Juxtaposed to this study is the mounting evidence that iron overloads — or a body incapable of properly breaking iron down — can influence how long we can expect to live, in addition to our healthspan.
"Our ultimate aim is to discover how aging is regulated and find ways to increase health during aging," said Joris Deelen, a researcher of the biology of ageing from the Max Planck Institute for Biology of Ageing in Germany, according to a blog post on the University of Edinburgh website.
"The 10 regions of the genome we have discovered that are linked to lifespan, healthspan, and longevity are all exciting candidates for further studies," he added.
Judging from this latest study into longevity, people in their 30s or younger may one day have the means to lower their blood iron levels, and thus extend their years on the Earth as they near the end of a typical human lifespan.