The Feeling of Hunger Itself May Slow Aging

A new study from the University of Michigan has revealed that the feeling of hunger itself may be enough to slow aging.

These intriguing findings drove first author Kristy Weaver, Ph.D., principal investigator Scott Pletcher, Ph.D., and their colleagues to examine whether changes in the brain that prompt the drive to seek food could be behind longer life.

“We’ve sort of divorced [the life-extending effects of diet restriction] from all of the nutritional manipulations of the diet that researchers had worked on for many years to say they’re not required,” said Pletcher. “The perception of not enough food is sufficient.”

To do this, they induced hunger in flies in several ways. The first was to alter the amount of branched-chain amino acids, or BCAAs, in a test snack food and later allow the flies to freely feed on a buffet of yeast or sugar food. Flies fed the low-BCAA snack consumed more yeast than sugar in the buffet than did the flies fed the high-BCAA snack. This kind of preference for yeast over sugar is one indicator of need-based hunger.

The researchers noted that this behavior wasn’t due to the calorie content of the low-BCAA snack; in fact, these flies consumed more food and more total calories. When flies ate a low-BCAA diet for life, they also lived significantly longer than flies fed high-BCAA diets.

To look at hunger apart from dietary composition, they used a unique technique, activating neurons associated with the hunger drive in flies using exposure to red light, using a technique called optogenetics. The red-light activated flies also lived significantly longer than flies used as a control.

What’s more, the team was able to map the molecular mechanics of hunger to changes in the epigenome of the neurons involved. These changes can affect how much of specific genes are expressed in the brains of flies and, consequently, their feeding behavior and aging.

They next plan to examine how the drive to eat for pleasure, present in both flies and people, may also be linked to lifespan.

Sources:

K. J. Weaver, R. A. Holt, E. Henry, Y. Lyu, S. D. Pletcher. Effects of hunger on neuronal histone modifications slow aging in Drosophila. Science, 2023; 380 (6645): 625 DOI: 10.1126/science.ade1662

Michigan Medicine – University of Michigan. “The feeling of hunger itself may slow aging in flies.” ScienceDaily. ScienceDaily, 11 May 2023. <www.sciencedaily.com/releases/2023/05/230511164451.htm>.

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