February 12, 2014
Obesity, Gut Bacteria Link Found In People Who Live In Cold Climates
Lee Rannals for redOrbit.com - Your Universe Online
People who live in colder climates have adapted to the harsher conditions by adding a gut bacteria associated with obesity.Humans have a gut full of bacteria to help digest food and past studies have linked an increase in the proportion of bacteria from the Firmicutes group to obesity and a decrease in the proportion from the Bacteroidetes group. The research, published in the Royal Society Journal Biology Letters, says that this bacteria mix-up is also found in people who live in colder climates.
Indigenous populations have been able to adapt to colder climates by increasing their body mass, inspiring Taichi Suzuki, a PhD student from the University of California Berkeley's Integrative Biology department, for this study.
The researcher used data on gut bacteria from 1,020 healthy individuals from 23 populations around the world, which included China, Europe, Malawi, Venezuela and Africa. He looked to see if Firmicutes increased and Bacteroidetes decreased with the change in latitude.
"What I found was that human populations living in colder regions - high latitudes - have a microbial composition associated with obesity," Suzuki said in a statement. "There is a correlation between gut composition and latitude and that's pretty interesting. Microbes could be driving the body mass of animals in different climates."
While being fat is looked down upon, Suzuki says in the past it would have been seen as an attribute to help survive colder temperatures. He said that microbes helped humans adapt to cold climate by digesting food more efficiently and giving us more energy stores in the form of fat.
The PhD student studied the gut microbes of mice from North and South America to confirm this correlation. He said the same pattern can be seen in mice as he found in humans.
“Mice living in cold places are heavier and have the obese-associated microbes,” explained Suzuki.
Next, Suzuki plans to transplant microbes from heavy cold-climate mice to lean warm-climate mice to see if they can induce obesity. If the microbes cause obesity, then Suzuki suggests that microbes are driving the pattern. However, if the transplant doesn’t induce obesity then it could be that microbes in the heavy cold-climate mice are not causing obesity, but are a consequence of diet or genetics.
Suzuki says that his findings could one day help pharmaceutical companies developed tailored medication for obese individuals.