Hunger hormone affects depression, says US study

There’s a possible link between hunger and depression. When hungry, the body produces a hormone called ghrelin, which acts as an antidepressant. The catch is that those not suffering from hunger are likely not to have much ghrelin.

The BBC story indicates this is a nice, complex, possible therapy… for some:

The Nature Neuroscience study found mice with increased levels of the hormone showed fewer signs of depression and anxiety.

Experts said the idea was interesting but further studies were needed.

Ghrelin is released by the empty stomach into the bloodstream before moving to the brain, where it triggers feelings of hunger.

…In the latest study, Dr Jeffrey Zigman and colleagues restricted the food intake of laboratory mice for 10 days, causing their ghrelin levels to quadruple.

Compared with mice who had free access to food, the calorie-restricted mice showed lower levels of depression and anxiety when subjected to mazes and other behaviour tests.

This means you can be starving but not depressed. Anyone who’s had both would take starving. (I’ve had both. I’m six foot, and when I was 17 I weighed six stone. Starving’s relatively easy to fix.) Mice genetically engineered to be unable to respond to the hormone definitely had greater signs of depression and anxiety. You’ll be glad to hear this bit of hormonal hubris has a prehistoric basis:

"Our findings in mice suggest that chronic stress causes ghrelin levels to go up, and that behaviours associated with depression and anxiety decrease when ghrelin levels rise," said Dr Zigman, a researcher at UT Southwestern Medical Center in Dallas.

"An unfortunate side effect, however, is increased food intake and body weight," he added.

He said the results made sense from an evolutionary standpoint, as hunter-gatherers may have had a survival advantage in remaining calm and collected in times of hunger in order for them to successfully find food.

The researchers are now hoping to look at the antidepressant effect of the hormone in conditions such as anorexia.

So the choice is still being a happy, mentally well-adjusted, hoping to be overeating, skeleton, or depression. I guess you could be a happy, fashionable, skeleton. As a concession to scientific tradition, the article ends with a traditional disclaimer: "The role of ghrelin in the gut and in the brain are likely to be completely different," he (Dr Stephen Bloom, UK appetite regulation expert) said. It probably means your brain can still think you’re overweight, while your stomach is telling you you’re starving. That would explain a few things. My experience, naturally, was sort of . I was eating five meals a day when I had depression, and it really helped. I would have made a great hunter-gatherer… of Doritos, lamingtons, meringues.. steaks, buses…