10 November 2009

Feeding Stress: Sweet-Cycling the Amygdala

The central amygdala is involved in fear, stress, and anxiety responses. Researchers at Scripps have discovered that the central amygdala's stress response is elevated 5X when a dieter accustomed to sweet foods is switched to normal chow.
"We found that rats cycled in this way between palatable food and less tasty, but otherwise acceptable, food, begin to binge on the sweet food, stop eating their regular food, and show withdrawal-like behaviors often associated with drug addiction. As in addiction to drugs or ethanol, the brain's stress system is involved in each of these changes."

...the researchers looked at the involvement of the brain's stress system -- which had been shown to contribute to patterns of drug and alcohol binging and withdrawal -- in underpinning these behaviors.

To do this, the team measured levels of stress-related corticotropin-releasing factor (CRF) mRNA and peptide in an area of the brain known as the central amygdala, which is involved in fear, anxiety, and stress responses. Indeed, the researchers found that the diet-cycled group on normal chow displayed five times the control group's levels of CRF. Only when the diet-cycled group was fed sweet food did CRF levels return to normal.

"CRF is a key stress neuropeptide," said Cottone. "In observing the activation of the amygdaloid CRF system during abstinence from sweet foods, we understood the causes of recurrent dieting failures."

...To confirm these results and to see whether blocking CRF could reverse some of the effects of diet cycling, the researchers turned to a compound called R121919 (a small molecule CRF1 receptor antagonist).

When administered to the diet-cycled rats, the compound blunted the bingeing on sweet chow, as well as the lackluster pursuit of regular chow and the anxiety-associated behaviors during this part of the diet cycle. As in similar studies modeling alcoholism, on a molecular level diet-cycled rats showed greater sensitivity to the ability of the CRF1 receptor antagonist to reduce central amygdala synaptic transmission of the neurotransmitter GABA, which plays an important role in regulating neuronal excitability. _SD

Very interesting.   High levels of stress underlie many addictions.  Of course, these are rats, not people.  It looks as if the same sort of CRF receptor blocker can blunt addictive behaviours in humans -- to foods, drugs, and other dysfunctional behaviours. We might soon see 13 step anti-addiction programs opening up.  The 13th step would be the use of CRF receptor bloockers.

Do you think they could put those blockers in ice cream?

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Blogger Bruce Hall said...

It takes anywhere from 1 day to 2 weeks to adapt to a low-carb/high protein/high fat diet, after which the sugar cravings virtually disappear.

High carb/sugar diets trigger insulin and our bodies get used to burning sugar for fuel. Men can switch from burning sugars to burning fats and protein for fuel faster than women, so they can become non-addicted quickly. Women's metabolisms take longer to adapt to burning fats for fuel.

Stress and sugar-based diets reinforce sugar cravings. High fat/protein diets are not as susceptible to that cycle.

It's simply a matter of what your body has adapted to for fuel.

Tuesday, 10 November, 2009  
Blogger al fin said...

Yes, very true. But what is the first reaction to an attractive photo of ice cream?

The desire for sugar and sweets goes deeper than the reflexive cravings that go away after a few weeks.

Sometimes it seems as if we are born with a desire for sweet tasting things.

I fear it never truly goes away for most of us.

Friday, 13 November, 2009  
Blogger jimpurdy1943@yahoo.com said...

What a ridiculous study.

Millions of low-carb and Atkins dieters are well-acquainted with the "Atkins flu" that often accompanies the switch to to a new fuel.

That's a perfectly natural process.

What is outrageous is that shills for BigPharma are, predictably, trying to find some bizarre and profitable chemicals to interfere with a natural process.

Sunday, 29 November, 2009  

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