Calorie Overload Makes Brain Go Haywire

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Calorie Overload Makes Brain Go Haywire

 

Overeating makes the brain go haywire, prompting a cascade of damage

that may cause diabetes, heart disease and other ills, U.S. researchers

reported on Thursday.

 

Eating too much appears to activate a usually dormant immune system

pathway in the brain, sending out immune cells to attack and destroy

invaders that are not there, Dongsheng Cai of the University of

Wisconsin-Madison and colleagues found.

The finding, reported in the journal Cell, could help explain why

obesity causes so many different diseases. It might also offer a way to

prevent obesity itself.

" This pathway is usually present but inactive in the brain, " Cai said in

a statement.

 

Obesity is a growing global problem, with 1.8 billion people estimated

to be overweight or obese in 2007. Drugs marketed so far to fight

obesity have only limited success and, often, severe side-effects.

 

Cai's team worked in mice, seeking to explain studies that have shown

that obesity causes chronic inflammation throughout the body. This

inflammation is found in a range of diseases related to obesity,

including heart disease and diabetes.

 

They homed in on a compound known as IKKbeta/NK-kappaB.

Immune cells such as macrophages and leukocytes use it but Cai's team

found it in the hypothalamus, a part of the brain linked with metabolism

in mice and humans alike.

 

" The hypothalamus is the 'headquarters' for regulating energy, " they

wrote.

They found high levels of the compound there but it was normally

inactive.

When they fed mice a high-fat diet, it became extremely active. And when

it was active, the body ignored signals from leptin, a hormone that

normally helps regulate appetite, and insulin, which helps convert food

into energy.

 

Stimulating IKKbeta/NK-kappaB made the mice eat more, while suppressing

it made them eat less.

 

Cai believes his team has discovered a master switch for the diseases

caused by overeating.

 

" Hypothalamic IKKb/NF-kB could underlie the entire family of modern

diseases induced by overnutrition and obesity, " his team wrote.

 

" Knocking out " the gene using genetic engineering kept mice eating

normally and prevented obesity. This cannot be done in people but Cai

believes a drug, or even gene therapy, might work.

 

Copyright Reuters

 

RB, Thinking of cutting back on the five-pizza " snacks "