We recently reported on a study that concluded the main threat to the health of night owls was the blowback they get from “day larks.” However, there’s apparently a big difference between preferring to simply stay up late and pulling an all-nighter, especially on an irregular basis. A University of Colorado (CU Boulder) and Women’s Hospital (BWH) in Boston study of 270,000 people published last February in Diabetes Care found that people who occasionally stay up all night are far more likely to contract Type 2 diabetes—the schedule is also implicated in a higher incidence of cardiovascular disease and cancer. Now, a new study from UC Boulder may have discovered at least part of the reason why: even a single all-nighter messes with your blood chemistry.
15 million Americans work night shifts either permanently or periodically. The CU Boulder/BWH researchers examined data from the UK Biobank pertaining to males from 38 to 71 and discovered that people who irregularly handled night shifts or who were on rotating schedules were 44% more likely to have Type 2 diabetes, with the odds going up with the number of nights worked. (Surprisingly, permanent night workers showed no such increase in the chances of getting diabetes—it seems that their bodies had over time adapted to their workday/night.)
This makes sense in light of the new CU boulder findings. Its authors enlisted six healthy males in their 20s who spent six days and nights in a setting where their meals, activity, sleep and, light were controlled. For the first two days, the experiment mimicked a normal schedule. The men were then moved to a reverse schedule of sleeping eight hours a day and being active eight hours a night.
Throughout the study, the researchers analyzed the levels and time-of-day-behaviors of 1,129 blood proteins. Study lead author Christopher Depner tells CU Boulder Today, “By the second day of the misalignment we were already starting to see proteins that normally peak during the day peaking at night and vice versa.” They ultimately identified 129 proteins whose rhythms were being disrupted by the scheduling.
One of these was glucagon, which manages the release of sugar from the liver into the bloodstream. Glucagon usually hits its highest levels during the day, but for the subjects awake at night, that flipped—not only did the peaks occur at night, but even more concerning was that those peaks indicated abnormally high levels of the protein. This could be what’s leading to the increase in diabetes.
The experiment also revealed that the night shifters burned 10% fewer calories during activity, perhaps due to the higher levels of fibroblast growth factor 19 observed—this protein is believed to influence the way in which energy is expended. With weight gain associated with Type 2 diabetes, this could also be a contributing factor.
Another interesting finding was that 30 blood proteins are creatures—if we can use that word—of habit, with most of them reaching their highest levels between 2 pm and 9 pm. This suggests that more accurate blood testing for these proteins could be achieved by considering their natural timing when drawing blood. An even more significant takeaway is, “If we know the proteins that the clock regulates, we can adjust the timing of treatments to be in line with those proteins,” says Depner.
As for the people most identified as being at risk in these studies, when handed unavoidable irregular night work the best defense, says Celine Vetter of CU Boulder, is to eat right, exercise, and make sure to get plenty of sleep when you can. There’s also at least one recent study that suggests you can make up lost ground by sleeping in on weekends.
- The jaw bones of an 8-million-year-old ape were discovered at Nikiti, Greece, in the '90s.
- Researchers speculate it could be a previously unknown species and one of humanity's earliest evolutionary ancestors.
- These fossils may change how we view the evolution of our species.
Homo sapiens have been on earth for 200,000 years — give or take a few ten-thousand-year stretches. Much of that time is shrouded in the fog of prehistory. What we do know has been pieced together by deciphering the fossil record through the principles of evolutionary theory. Yet new discoveries contain the potential to refashion that knowledge and lead scientists to new, previously unconsidered conclusions.
A set of 8-million-year-old teeth may have done just that. Researchers recently inspected the upper and lower jaw of an ancient European ape. Their conclusions suggest that humanity's forebearers may have arisen in Europe before migrating to Africa, potentially upending a scientific consensus that has stood since Darwin's day.
Rethinking humanity's origin story
The frontispiece of Thomas Huxley's Evidence as to Man's Place in Nature (1863) sketched by natural history artist Benjamin Waterhouse Hawkins. (Photo: Wikimedia Commons)
As reported in New Scientist, the 8- to 9-million-year-old hominin jaw bones were found at Nikiti, northern Greece, in the '90s. Scientists originally pegged the chompers as belonging to a member of Ouranopithecus, an genus of extinct Eurasian ape.
David Begun, an anthropologist at the University of Toronto, and his team recently reexamined the jaw bones. They argue that the original identification was incorrect. Based on the fossil's hominin-like canines and premolar roots, they identify that the ape belongs to a previously unknown proto-hominin.
The researchers hypothesize that these proto-hominins were the evolutionary ancestors of another European great ape Graecopithecus, which the same team tentatively identified as an early hominin in 2017. Graecopithecus lived in south-east Europe 7.2 million years ago. If the premise is correct, these hominins would have migrated to Africa 7 million years ago, after undergoing much of their evolutionary development in Europe.
Begun points out that south-east Europe was once occupied by the ancestors of animals like the giraffe and rhino, too. "It's widely agreed that this was the found fauna of most of what we see in Africa today," he told New Scientists. "If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?"
He recently outlined this idea at a conference of the American Association of Physical Anthropologists.
It's worth noting that Begun has made similar hypotheses before. Writing for the Journal of Human Evolution in 2002, Begun and Elmar Heizmann of the Natural history Museum of Stuttgart discussed a great ape fossil found in Germany that they argued could be the ancestor (broadly speaking) of all living great apes and humans.
"Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa," Begun said in a statement then. "It suggests that the great ape and human lineage first appeared in Eurasia and not Africa."
Migrating out of Africa
In the Descent of Man, Charles Darwin proposed that hominins descended out of Africa. Considering the relatively few fossils available at the time, it is a testament to Darwin's astuteness that his hypothesis remains the leading theory.
Since Darwin's time, we have unearthed many more fossils and discovered new evidence in genetics. As such, our African-origin story has undergone many updates and revisions since 1871. Today, it has splintered into two theories: the "out of Africa" theory and the "multi-regional" theory.
The out of Africa theory suggests that the cradle of all humanity was Africa. Homo sapiens evolved exclusively and recently on that continent. At some point in prehistory, our ancestors migrated from Africa to Eurasia and replaced other subspecies of the genus Homo, such as Neanderthals. This is the dominant theory among scientists, and current evidence seems to support it best — though, say that in some circles and be prepared for a late-night debate that goes well past last call.
The multi-regional theory suggests that humans evolved in parallel across various regions. According to this model, the hominins Homo erectus left Africa to settle across Eurasia and (maybe) Australia. These disparate populations eventually evolved into modern humans thanks to a helping dollop of gene flow.
Of course, there are the broad strokes of very nuanced models, and we're leaving a lot of discussion out. There is, for example, a debate as to whether African Homo erectus fossils should be considered alongside Asian ones or should be labeled as a different subspecies, Homo ergaster.
Proponents of the out-of-Africa model aren't sure whether non-African humans descended from a single migration out of Africa or at least two major waves of migration followed by a lot of interbreeding.
Did we head east or south of Eden?
Not all anthropologists agree with Begun and his team's conclusions. As noted by New Scientist, it is possible that the Nikiti ape is not related to hominins at all. It may have evolved similar features independently, developing teeth to eat similar foods or chew in a similar manner as early hominins.
Ultimately, Nikiti ape alone doesn't offer enough evidence to upend the out of Africa model, which is supported by a more robust fossil record and DNA evidence. But additional evidence may be uncovered to lend further credence to Begun's hypothesis or lead us to yet unconsidered ideas about humanity's evolution.
