Thursday, September 07, 2006

Your post-lunch-lag is only natural: scientists - Discovery Reports Canada

Discovery Reports Canada
Its always good to see scientific research back up something that almost everyone experiences on a daily basis, in this case, the usual lethargy after lunch.


Updated Thu. Jun. 1 2006 3:41 PM ET

Valerie Iancovich,

Sugar slows the brain

Scientists have long-known that people and animals get tired after eating, but this University of Manchester study is the first to shed some light on how certain brain cells simply turn off after we eat.

When you need sustenance, you're more alert: this is a basic survival mechanism that helps keep you spry until you get proper nourishment. The neurons that normally work to keep you alert when you're hungry are blocked after you've consumed the glucose (sugar) in your meal, the researchers found.

How blocked cells = less gusto

Conducting tests on mice, the team found that glucose interferes and 'blocks' the neurons that make the proteins that help regulate consciousness (orexins).

These orexins respond to "finely orchestrated changes in arousal, food seeking, hormone release and metabolic rate to ensure that the brain always has adequate glucose," lead researcher Denis Burdakov, says.

Other applications

Pinpointing the role of the orexin cells could help scientists to better understand conditions like narcolepsy and obesity as well as how the cells affect learning, reward-seeking, and addiction, the researchers say.

Alternatives to shut-eye

Regardless of the science, chances are your workplace won't be installing cots or passing-out pillows anytime soon. But, you may want to consider what you're eating to dodge the dreariness, the "study provides neurophysiological rationale for existing studies that show that foods that are more effective in elevating blood glucose (carbohydrate-rich foods) would make you more sleepy, than, say, salads or protein meals," Dr Burdakov tells

The study is published in the journal Neuron.