Health & Wellbeing

"Genetic brake" could help combat sugar cravings

"Genetic brake" could help com...
A pair of nerve cells in the throat may be the key to reducing sugar cravings in fruit flies, and possibly humans
A pair of nerve cells in the throat may be the key to reducing sugar cravings in fruit flies, and possibly humans
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The green fluorescence marks where the IR60b genes are being expressed, in the fruit fly's throat
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The green fluorescence marks where the IR60b genes are being expressed, in the fruit fly's throat
A pair of nerve cells in the throat may be the key to reducing sugar cravings in fruit flies, and possibly humans
2/2
A pair of nerve cells in the throat may be the key to reducing sugar cravings in fruit flies, and possibly humans

As unhealthy as it is, sugar is a hard habit to kick, not least because it's delicious. Normally, taste receptors in the mouth pick up the sweetness and tell us to keep eating, but researchers have now found one receptor that does the opposite – for fruit flies, anyway. A pair of neurons in the throat has been found to tell the insects when they've had enough sugar, a find which could potentially lead to a new way to combat sugar cravings in humans.

Hailing from Yale, the researchers stumbled onto the discovery while investigating IR60b, a gene that was only being expressed in nerve cells in the fruit flies' throats. Its function a mystery, the team tested IR60b using optogenetics, a technique that allows scientists to switch certain genes on and off using pulses of light.

The green fluorescence marks where the IR60b genes are being expressed, in the fruit fly's throat
The green fluorescence marks where the IR60b genes are being expressed, in the fruit fly's throat

To their surprise, when the researchers turned off either the gene or the nerve cells themselves, the flies gorged themselves on more sucrose than they normally would. By the same token, when the nerve cells were triggered, the insects generally ate less, which suggests that IR60b plays a key role in regulating their sugar intake. That said, it wasn't an instant off-switch: it takes some time for the "genetic brake" to activate, which allows the flies a little time to enjoy their meal before they decide enough is enough.

"This was very surprising because most sugar-sensing taste cells promote eating, but these are doing just the opposite," says John Carlson, senior author of the study.

The next step for the researchers is to see whether mammals like us might use a similar system for regulating our sugar intake. They're hopeful this may be the case because Carlson points out that humans and fruit flies very often share similarities when it comes to the control of fundamental processes such as eating. If so, it could give us a new weapon in the fight against obesity.

The research was published in the journal eLife.

Source: Yale University

1 comment
BartyLobethal
Sugar-loving bacteria that live in your intestines play a far greater role. The trick to quitting sugar is to starve the little buggers to death. The populations are greatly reduced after a sugar-free month, after which time the constant desire for sweetness becomes more and more intermittent. In my case, it took around 9 months for the cravings to completely disappear. Almost 2 years in, I can stand in front of a pile of lollies or cake and not even feel tempted.