‘Hunger’ hormone may help the brain make new memories
You want the best for your kids, but sometimes it’s not clear what that is. Nutrition for a growing body is important, and you want them to get the nourishment they need to grow, from their skeleton to their brain… and four-year-olds with low blood-sugar are awful to be around. On the other hand, a bit of hunger may have some benefits, at least as far as memory performance goes. Scientists are getting closer to pinpointing the exact mechanisms at work, but it looks like a hormone from a hungry tummy get your body to make more brain cells.
The hormone in question is called ghrelin, and it’s secreted when the stomach is empty. When ghrelin reaches your brain, it triggers a sense of hunger and gastric acid production, basically setting you up for meal time. Once your stomach stretches out a bit, presumably from being filled with food, the ghrelin production drops off and a different hormone, leptin, heads up to the brain to let you know to relax and stop eating.
Boosting brain growth
Longer-term exposure to ghrelin may have some other effects on the brain though. Animals on low-calorie diets that presumably leave them feeling a bit peckish seem to do better on cognitive tasks than their well-fed peers. Mice given injects of extra ghrelin probably felt a bit of the munchies, but also performed better on learning and memory tests. In the most direct test of this relationship, mouse neurons in a petri dish were bathed in ghrelin, it stimulated more growth of new brain cells. In an actual mouse, those new cells would likely help the mouse form new memories, explaining what’s boosting their test scores.
While mice might be ready to learn when they want a snack, this hasn’t been tested directly in humans. Lower calorie diets have been found to offer some health benefits, but most discussions of fasting for memory-boosts are anecdotal at this point. Intermittent fasting does raise ghrelin levels in the body, but we don’t know if this offers the same benefits to people as it does to mice. In the mean time, researchers are looking at ghrelin as a way to help trigger brain cell-growth in people with Parkinson’s disease, so we may soon settle how being hungry helps your brain (or doesn’t.) In the mean time, hangry kids are a big enough incentive from my perspective to avoid keeping them too hungry on purpose.
My second grader asked: So if I have a spelling test should I skip my lunch so I remember things better?
Nope. Some studies have found that being hungry impairs cognition in humans. If ghrelin does pan out promote brain cell growth, it also wouldn’t work on such a short timescale. The new brain cells need time to grow and put into use, and even then are more about making it easier to build new memories, not retrieve the memories you already have.
Source: Hungry stomach hormone promotes growth of new brain cells by Clare Wilson, New Scientist