Your Weight May Be At The Mercy Of Your Hypothalamus

Remember how you were told as a kid not to bump your head because you lose brain cells that don't grow back? Research over the past few decades has de-bunked that myth - to a certain extent. New neurons do form into adulthood in a process called neurogenesis. A recent study from John Hopkins goes even further and shows that neurogenesis in the hypothalamus might play a large factor in determining how much you eat, and may explain why it might be hard to lose weight.

Previously neurogenesis was only recognized in two parts of the brain: the hippocampus which deals with memory, and the olfactory bulb for smell. By using mice study leader Associate Professor Seth Blackshaw Ph.D has now found evidence that this also occurs in the hypothalamus, the area concerning hunger, thirst, sleep, and body temperature along with a variety of other body functions.

The team of researchers injected mice with bromodeoxyuridine (BrdU), an easily identifiable compound that incorporates itself into replicating DNA. The idea behind this was to identify whether there was a high level of cell growth. This compound was found in the hypothalamus a few days later.

The cells where BrdU was found were tanycytes, which often times form neurons. To confirm that the tanycytes were producing neurons, the team then bred mice with a fluorescent protein in their tanycytes. After a few weeks, the team found fluorescent neurons in these mice, indicating that they had come from the tanycytes.

To test how this neurogenesis affected the mice, they fed a group of mice high-fat chow based on the established fact that animals raised on a high-fat diet have a greater risk of metabolic syndrome and obesity.

The researchers then split the group in two and used X-rays to kill off any neurogenesis that occurred in one of the groups. The result? The mice with no neurogenesis gained less weight than those who showed signs of neurogenesis, even though the latter group was more active.

"People typically think growing new neurons in the brain is a good thing - but it's really just another way for the brain to modify behavior," Blackshaw explains.

In other words, losing weight may not be as simple as being more active or eating the right diet. The brain's growth may have something to do with it, and unless we all start X-raying our new neurons, our weight may be at the mercy of our brain.