People from cold climates may have more healthy brown fat and with it, a lowered risk of metabolic disorders and obesity.
A new study found that men who spend time in lower temperature environments can pass on healthy brown fat to their children.
The study was conducted by researchers from ETH Zurich, a mathematics and science university, and published in the journal Nature Medicine.
First, the researchers wanted to better understand the correlation between ambient temperature before conception and the formation of brown fat.
CT scan images of 8,400 adult patients were analyzed for the study, and those participants first conceived during the colder months had more active brown adipose tissue than those conceived during warmer months.
Next, the researchers conducted several experiments with mice to see if this correlation between temperature at conception and brown fat held true.
Groups of mice were kept in either moderate or cool environments and after they mated, the researchers examined the offspring.
For female mice, the temperatures had no impact on how much brown tissue was passed onto offspring, but the babies of males who were kept in cooler temperatures had more active brown fat than the offspring of males kept in moderate environments.
The offspring of males from cooler temperatures were also better equipped to combat obesity even on a high-fat diet.
After studying the sperm of the male mice the researchers were able to show that temperature did impact healthy brown fat formation in offspring.
A possible explanation for why cold climates influence brown adipose formation is that burning brown fat cells produces body heat and so males from cold temperatures are predisposed to thrive in that environment.
“Perhaps this protects them from icy cold, which might explain why this epigenetic mechanism has been selected for, in the course of evolution,” says Christian Wolfrum, the leader of the research. “Until now, the assumption was that this had something to do with the temperatures people experienced during their lifetime, but our observations suggest that temperatures prior to conception might also affect later levels of brown fat.”