Ghrelin is a hormone released by your stomach to alert your brain and tell you that you’re hungry. Accordingly, your ghrelin levels increase during periods of fasting or when you’re hungry, then drop again a few hours after you’ve eaten.
While this information hasn’t changed, something that’s not so commonly known about ghrelin has been reinforced by recent studies. And it could pave the way for the development of new treatments for brain-related conditions. Reason being? Well, there’s much more to ghrelin than being a mere ‘hunger hormone’.
According to Dr. Jeffrey Davies, associate professor of molecular neurobiology at U.K.’s Swansea University, apart from signalling hunger, ghrelin can also boost cognitive abilities by stimulating brain cell growth and improving memory. Or at least that’s what it does in mice.
Based on the studies they conducted, Davies and his team confirmed that ghrelin can stimulate neurogenesis, the process whereby brain cells divide and multiply. They derived this conclusion from the observation that after injecting mice with ghrelin, they performed better in learning and memory tests, and the number of neuron connections in their brains seems to have increased. And it is most likely because the hormone might have activated a gene called fibroblast growth factor, which is known to trigger neurogenesis.
Going further, the addition of new brain cells resulted in improved memory because young brain cells are believed to be more excitable and responsive to new environments. As Davies explained to New Scientist, “These neurons will fire more easily than old neurons, and they set in play a new memory.” Meaning, the more new brain cells, the better the ability to form new memories.
Because of its effect on brain cells, this discovery about ghrelin may have some significance on neurodegenerative conditions like Parkinson’s disease. In some experiments involving mice brain cells that model Parkinson’s disease, Davies’ team found that ghrelin seemed to protect brain cells from dying. In terms of humans, a study revealed that patients with Parkinson’s dementia had lower levels of ghrelin compared with people who didn’t have the disease.
While it may be hard to believe that deliberately allowing one’s self to go hungry might be beneficial to brain function, especially when you think about how extra-difficult it was to answer those college test exams while your stomach was grumbling from hunger, research does seem to suggest that fasting helps improve, not impair, a person’s mental abilities. As long as it’s done right.
Essentially, it’s no different from going on a diet. New Scientist cited the 5-2 diet as an example of one that might be effective for this purpose. When on a 5-2 diet, a person will eat normally for 5 days, then limit calorie intake to about 500 calories per day for 2 days. This should result in higher ghrelin levels and possibly, the triggering of neurogenesis and improved memory function.
To be clear, though, one should not expect fasting to produce immediate improvement on memory or brain power. After all, young brain cells need a few weeks to ‘grow’ before they can start functioning as they should.
Davies work was recently presented at the British Neuroscience Association conference.