This article is more than 5 years old. Information may no longer be current.
Fragile bones linked to inactivity over millenia
Click Here to Manage Email Alerts
Human bones have become much lighter and more fragile since the invention of agriculture, mostly attributable to a more sedentary lifestyle that arose during the switch from foraging to farming, according to recent study findings published in the Proceedings of the National Academy of Sciences.
Research that examined thousands of years of human evolution revealed that bones are more susceptible to breaking now than they were 7,000 years ago.
“Contemporary humans live in a cultural and technological milieu incompatible with our evolutionary adaptations,” Colin Shaw, PhD, of the University of Cambridge’s Phenotypic Adaptability, Variation and Evolution Research Group, said in a press release. “There’s seven million years of hominid evolution geared towards action and physical activity for survival, but it’s only in the last say 50 to 100 years that we’ve been so sedentary — dangerously so. Sitting in a car or in front of a desk is not what we have evolved to do.”
Samples of human femurs from the archeological record were x-rayed, along with femora from other primate species. Researchers focused on the femoral head to analyze the trabecular bone from four distinct human populations representing mobile hunter-gatherers and sedentary agriculturalists.
The hunter-gatherer population was found to have a higher amount of actual bone relative to air.
“Trabecular bone has much greater plasticity than other bone, changing shape and direction depending on the loads imposed on it; it can change structure from being pin or rod-like to much thicker, almost plate-like,” Shaw said. “In the hunter-gatherer bones, everything was thickened.”
Shaw and colleagues dispute the theory that over time bones became lighter because of lack of food.
“The fact is, we’re human, we can be as strong as an orangutan — we’re just not, because we are not challenging our bones with enough loading, predisposing us to have weaker bones so that, as we age, situations arise where bones are breaking when, previously, they would not have,” Shaw said.
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts