Feeling hungry may protect brain against Alzheimer's

The feeling of hunger itself may protect the brain against Alzheimer's disease, according to a new study.
The study in mice suggests that mild hunger pangs, and related hormonal pathways, may be as important to the much-discussed value of "caloric restriction" as actually eating less.
Caloric restriction is a regimen where an individual consumes fewer calories than average, but not so few that they become malnourished.
Studies in many species have suggested that it could protect against neurodegenerative disorders and extend lifespans, but the effect has not been confirmed in human randomised clinical trials.
The authors of the new study, published in journal PLOS ONE, argue that hormonal signals are the middlemen between an empty gut and the perception of hunger in the brain, and that manipulating them may effectively counter age-related cognitive decline in the same way as caloric restriction.

"This is the first paper, as far as we are aware, to show that the sensation of hunger can reduce Alzheimer's disease pathology in a mouse model of the disease," said Inga Kadish, from the University of Alabama at Birmingham.

"If the mechanisms are confirmed, hormonal hunger signalling may represent a new way to combat Alzheimer's disease, either by itself or combined with caloric restriction," Kadish said.
The team theorises that feeling hungry creates mild stress. That, in turn, fires up metabolic signalling pathways that counter plaque deposits known to destroy nerve cells in Alzheimer's patients.
To study the sensation of hunger, the research team analysed the effects of the hormone ghrelin, which is known to make us feel hungry.

They used a synthetic form of ghrelin in pill form, which let them control dosage such that the ghrelin-treated mice felt steadily, mildly hungry.
If it could be developed, a treatment that affected biochemical pathways downstream of hunger signals might help delay cognitive decline without consigning people to a life of feeling hungry, researchers said.