Health Highlights: Sept. 10, 2007

Some U.S. food companies already use symbols to indicate the nutritional value of their products. One New England supermarket chain uses a zero to three-star system to rate more than 25,000 food items on its shelves, theAPreported. In England, some food companies use a "traffic light" symbol to rank foods based on levels of fat, salt and sugar.

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Brain-Injured Soldiers Challenge U.S. Medical System

The thousands of American troops with blast-related traumatic brain injury (TBI) are proving a challenge for the U.S. medical system, according to theAssociated Press.

Blast-related brain injuries are markedly different from brain injuries caused by falls and car crashes.

"I've been in the field for 20-plus years dealing with TBI. I have a very experienced staff. And they're saying to me, 'We're seeing things we've never seen before,'" Sandy Schneider, director of Vanderbilt University's brain injury rehabilitation program, told theAP.

Doctors are learning that symptoms of blast-related TBI often overlap with post-traumatic stress disorder and both conditions must be treated.

The exact number of U.S. troops with blast-related TBI isn't known, but the numbers are straining the resources of the Department of Veterans Affairs, theAPreported.

About one-fifth of troops with mild TBI, and nearly all of those with moderate or severe TBI, will have prolonged or lifelong symptoms requiring continuing care, according to the U.S. military.

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Brains of Liberals and Conservative Differ: Study

When confronted with difficult choices, the brains of liberals and conservatives respond differently, says a New York University study in the current issue of the journalNature Neuroscience.

The study included 43 people who did a series of computer tests designed to evaluate their responses to cues to deviate from a well-established routine,Agence France-Pressereported.

While the participants did the computer tests, the researchers scanned activity in an area of the brain called the anterior cingulate cortex, which is strongly linked with the self-regulatory process of conflict monitoring.

The study found that the brains of participants who described themselves as liberals showed "significantly greater conflict-related neural activity" when they were prompted to deviate from normal routine. Conservatives showed less flexibility and refused to break from normal routine "despite signals that this ... should be changed," the researchers said.

The findings suggest that some people's political preferences may be hard-wired,AFPreported.