Washington: Eating too much French fries and burgers. Then, the effects would not only show up in your weight but also in your brain, scientists say.
Researchers at the Johns Hopkins University School of Medicine in the US have discovered that high-fat diets cause new brain cells in mice to sprout in an area of the brain that seems to regulate eating.
Interestingly, the new brain-cell growth was stopped, the mice gained less weight and stayed more active even while eating their "supersize" diet, the researchers said.
"We really don`t understand the function of these neurons in the normal brain," study researcher Seth Blackshaw was quoted as saying by LiveScience.
"Our data suggests that these neurons may have an important role in regulating feeding," he said, adding the finding may lead to developing new diet-regulating therapies
for humans too.
According to the team, the cells are located in a part of the brain, called the median eminence, which lies at the edge of a fluid-filled chamber and therefore outside of the
blood-brain barrier (which keeps toxic substances out of the brain), but it extends deep into the hypothalamus.
The hypothalamus plays a role in regulating how our bodies spend the energy they take in and sends out signals to the body through the pituitary gland to control hunger, thirst
Because the median eminence is in contact with areas of the body outside the blood-brain barrier, the researchers think it may be detecting chemicals in the blood and
transferring signals about the condition of the body into the hypothalamus, which can then make decisions about eating.
In the study, published in journal Nature Neuroscience, the researchers wanted to see how brain cells in the median eminence reacted to a high-fat diet, so they put mice on a
"Big Mac" diet -- which contained 60 per cent fat instead of the 35 per cent fat in regular mouse chow.
The researchers found that on the high-fat diet, creation of new brain cells in the median eminence increased from one per cent to five per cent.
When the researchers selectively turned off the new cell creation in this brain region, they found the mice gained about seven per cent less weight and were 15 per cent more
active than the other mice eating the fatty food.
"We have no idea if this happens in any species other than mice. In humans all the cells and the structures are conserved," Blackshaw said.
"I think there`s no reason to assume necessarily that this wouldn`t happen in humans, but I would be very careful into reading too much in these studies," Blackshaw added.
If this small connection to the hypothalamus does play a big role in regulating energy intake and use in humans, it could be a potential target for diet-regulating therapies,
especially since it is located on the outside of the blood-brain barrier.
If the region were inside the blood-brain barrier, that barrier would filter out any "foreign" chemicals used to regulate the growth of new brain cells there.
"The therapeutic potential is quite exciting," Blackshaw said. "The beauty of this region, this median eminence, is that it lies completely outside of the blood-brain barrier.
"Delivery of therapeutics to target and regulate neurons or regulate neurogeneration (the growth of new brain cells) could be made pretty specific."